Student Reports for Winter 2004
Arlene X. Ramirez
To find out what make up the color black.
What do I need?
Instructions to class:
I do as previous explained, (same as class).
What’s going on?
Most non-permanent markers use inks that are made of colored pigments and water. On a coffee filter, the water in the ink carries the pigment onto the paper. When the ink dries, the pigment remains on the paper.
In this experiment, you’re using a technique called chromatography. The name comes from the Greek words chroma and graph for "color writing." The technique was developed in 1910 by Russia botanist Mikhail Tvset. He used it for separating the pigments that made up plant dyes.
There are many different types of chromatography. In all of them, a gas or liquid (like the water in your experiment) flows through a stationary substance (like you r coffee filter). Since different ingredients in a mixture are carried along at different rates, they end up in different places. By examining where all the ingredients ended up, scientists can figure out what was combined to make the mixture.
Why does mixing many colors of ink make black?
Ink and paint get their colors by absorbing some of the colors in white light and reflecting others. Green ink looks green because it reflects the green part of white light and absorbs all the other colors. Red ink looks red because it reflects the red light and absorbs all the other colors. When you mix green, red, blue, and yellow ink, each ink that you add absorbs more light. That leaves less light to reflect to your eye. Since the mixture absorbs light of many colors and reflects very little, you end up with black.
Grade Level: Appropriate for Elementary Age grades 2-5
Time: Activity will last about 15-20 minutes
Materials: Straws, Ruler, Scissors, and Tape
Teacher Preparation: May prepare the pieces of tape cut to wrap the straws
Purpose: To guide students in investigating and observing the sound effects
That occurs when there is a change in the size and length of the straws. This will also teach students the notion of vibration and pitches that are made by blowing air into the straws. In addition, it also allows students to practice their measuring skills.
What is a pitch? What is sound? What can we conclude about the lengths of the straws and how it affects the sound of the straw? Does the texture and size of the straw change the sounds? What kind of instrument can we relate this to?
Conclusion: We can conclude that sound is effect by many variables. The level of which air is blown into the straw; the shape and size of the straw all make a difference in the outcome of the sound.
This activity is fun to do and the materials are easy to get. Children enjoy exploring the different sounds of things. It is also a great way for them to learn about vibrations and measurements. Also it is something that they can take home and play with.
Will the Candy Sink or Float?
1. To allow the students to do hands on experiment using lessons taught in class: density, buoyancy, and gravity.
2. The students will also be able to make a hypothesis, test, and conclude as to what are the properties of an object, which will float.
3. Test Archimedes Principle.
- Container (bowl, bottle cut in half, cup, etc.)
- Candy: Mints (hard candy)
Starburst Fruit Chews
Milky Way Miniatures
Kit Kat Bites
- Depending upon how many objects selected, 10-20 minutes
1. Working in groups of two or three, make predictions as to whether the provided objects will sink or float.
2. Make a chart and record your answers on the board.
3. Test each of the objects separately, and record your answers on the sheet provided.
4. After testing the objects record your findings on the board.
-Why do you think that certain objects float while others sank?
Buoyancy: the upward force that liquids exert against an object,
Displacement: the volume of water moved by a floating or sunken
Objective: To introduce students to air pressure and its affect on the objects around us.
· A peeled hard-boiled chicken egg
· A glass bottle or vase with a wide opening (opening should be slightly smaller than the width of the egg)
· Place the peeled egg on top of the bottle or vase to show others that it will not fit through the opening.
· Light two matches and let them burn for 5-10 seconds.
· Lift the egg from the bottle or vase and drop the burning matches into the bottle.
· Replace the egg immediately. (The egg may jump a little, but don't touch it…just watch and see what happens.)
· Allow the students to explain why the egg went into the bottle. (As the air was heated, it began to expand. Some of the air escaped and may have caused the egg to wobble. When the fire was extinguished, the air began to cool and contract. The egg has now sealed the bottle. There is now less air in the bottle causing unequal pressure to occur between the air in the bottle and the air outside the bottle. The greater air pressure on the outside pushes the egg into the bottle equalizing the air pressure inside and outside the bottle.)
· Define air pressure: air pushes on all surfaces that it touches. This push is called air pressure. (It may be helpful to talk about these subjects before the experiment so that the students may predict the air’s behavior more accurately.)
· Allow students to brainstorm how to get the egg out of the bottle without breaking the bottle or the egg. (Hint: turn bottle upside down and gently heat the closed end of the bottle and keep the open end cool.)
· Let students get in small groups to come up with another way to get the egg in the bottle besides the procedure that we used. Discuss the methods as a class and determine which method may work better.
Experiment # 25
Purpose: To teach students about surface tension and show how it applies to water.
Materials: Two 2 liter soda bottles for each group of students, duck tape, water, glitter (optional), food coloring (optional).
-Give each group of students (2-4 students is a good size) two 2 liter soda bottles without the caps.
-Have the students fill one of the bottles ¾ with water. If the bottle already has soda in it and the students wish to keep the color of the soda, the students can leave a little soda in it and fill it with water until the bottle is ¾ full with liquid.
-Place the bottle with liquid in it on a flat surface. Take the other empty bottle and place is upside down on the filled bottle so that the openings of the bottles are together.
-Duck tape the two bottles together tightly so that there is a firm seal. Make sure there is no significant amount of water when shaken. If there is make sure to seal the leaks with duck tape.
-Take the taped bottles to an area that can get wet. Turn the taped bottles upside down and give it a strong swirl. What happens?
Explanation: When the bottles are given a strong enough swirl, a whirlpool (vortex) is created in the bottle. The reason why the water does this is because water has a high surface tension. Surface tension is the cohesive forces between liquid molecules. The cohesive forces between molecules in a liquid are shared with all of the atoms surrounding the molecules. The molecules on the surface have no neighboring atoms on top so they form stronger forces on the neighboring atoms on the surface. This is surface tension. The higher the surface tension, the more the molecules want to stick to each other. The surface tension of water decreases significantly with temperature Surface tension is usually measured in dynes/cm., which is the force in dynes required to break a film of length 1 cm. The surface tension of water is 72 dynes/cm. at 25°C.
Things to think about:
-Will having objects in the water disturb the experiment?
-Once the whirlpool is spinning downward and the bottles were to be spun in the opposite direction, what would happen to the whirlpool?
-Would the same thing happen if the hole was smaller/bigger?
-If duck tape was used to shut one of the mouths closed and holes were put in it, would it have the same effect as the original experiment?
*Another experiment that involves surface tension in water: Have enough people in a swimming pool to border the swimming pool wall. The people swim in a constant circle going the same way. A small whirlpool is created.
The Mysterious Moving Ping-Pong Ball
Area of science: Physics
Grade level: 4 – 6
Strategy: in pairs or small groups
Time: 15 – 20 min.
Static electricity is based on the structure of the atom. An atom contains tiny positively charged particles called protons in its core and much smaller negatively charged particles called electrons, which revolve around the outside. Objects with opposite charges (positive and negative) will attract one another, while objects with like/same charges will repel.
To teach and help students gain a better understanding of “static electricity” using everyday objects.
The # of times you’ve rubbed the balloon
The distance the ping-pong ball traveled
10 – 15
30 and up
Contest #1 -
A. The goal is to get your ping-pong ball from one end of the table to the other end as fast as you can.
B. Place the ping-pong ball at one end of the table.
C. You may rub the balloon as many times as you want during the race.
D. The first team to get the ball to the other side wins!
Contest #2 -
A. Place the ping-pong ball at one end of the table.
B. Given 1 minute, rub the balloon against your hair as fast or as many times as you can. (You will not be allowed to “recharge” during the race.)
C. When time is up, try to move your ball as far as you could (as close to the other end as possible).
D. The team that moves the ball closes to the finish line (the other end) wins!
Questions to think about:
1. Do you think the ping-pong ball would have followed the balloon if you hadn’t rubbed the balloon against your hair?
2. Try using other objects (comb), did they cause the same effect as the balloon?
3. What would happen if you have two objects of the same charges? Would they attract or repel one another?
4. Try this at home: Make a very thin stream of water come out of your kitchen faucet. Comb your hair a few times and slowly bring the back of the comb toward the thin stream of water (do not let the comb touch the water). What does the water do? What do you think would happen if the comb got wet?
In the following activity, only one object (the balloon) is rubbed and charged with static electricity. It is then used to attract an uncharged/neutral object (the ping-pong ball). Opposite charges (positive and negative) attract while like charges (positive and positive or negative and negative) repel.
Jumping Rice: Static Electricity
Targeting Grade Levels: 2-4
Key Science Topics:
Charging electricity by friction and contact, static electricity
(electrons being transferred by friction when one material rubs against another)
Learning Outcomes: Observing, investigating, scientific method
Time Required: 15 min, 5 for setup and cleanup
Materials for each group of students:
· Small cup of Rice Krispies
· Paper plate
· Have the students recognize a question or a problem about charging electricity. (What would happen when one material rubs against another?)
· Have the students make and educated guess-hypothesis
· Let the students blow up their balloons
· Have the students charge their balloons by rubbing the balloon on their heads or on a wool cloth
· Let the students observe charging their own electricity by the attractive and repulsive forces
· Have the students empty a cup of Rice Krispies onto their plates and ask them to charge their balloons so that they can attract the Rice Krispies onto their balloons.
· Let the students observe the jumping rice and have them make some conclusions or experimental findings.
Teacher’s explanation to students about where electric charges come from: Material objects are made up of atoms. They are composed of electrons, protons, and neutrons. Normally objects have equal numbers of electrons and protons so they are electrically neutral. Now, if there is a little imbalance in the numbers, the object becomes electrically charged. An imbalance occurs when electrons are added or removed from an object. When you comb your hair, electrons transfer from your hair to the comb. Scuff your shoes across a rug and feel a shock as you reach the doorknob.
The Bubble Bomb
Grade level: 5-6
Next, hold the packet at the top of the bag until sealed. Once the bag is sealed drop the packet and shake it lightly
What’s is happening?
The bubbles in the Bubble Bomb are filled with carbon dioxide, a gas that forms when the vinegar (an acid) reacts with the baking soda (a base)
Example: cake rising due to chemical reaction of an acid and base. When you add the water and baking powder, it will fizz.
Some Questions to think about
1. Instead of using a paper towel, make your “time release packet” using a coffee filter, what do you think will happen?
2. Does changing the water temperature change your experiment?
Objective: Students will use inquiry and observational skills to determine Newton’s Third Law of Motion: for every action there is a reaction; for every force there is an equal and opposite force.
Materials: balloons, straws, tape, string
Construction and Procedure: First, cut string that is about 5-6 feet long. Put string though straw. Blow up balloon (but hold the end) and tape balloon to the straw. Hold onto the balloon end and one end of the string. Tape the other end of the string to wall. Or have the children get partners and have one child hold the end of the string. Let go of the balloon and watch it rocket to the end of the string. Have the children blow up different sizes of the balloon and see which one will go faster. Have them hold the string in an upward or downward position.
Conclusion: This activity demonstrates Newton’s Third Law of Motion. The balloon is using air pressure to move forward. By showing the students that when the air in the balloon is pushed out of the balloon, the escaping air pushes forward on the balloon, which makes it go forward. Students should also see that different amounts of air determine how fast or slow the balloon will travel.
19. Julie Halferty
Cooked Vs. Raw Egg
The Set up:
1) Take two eggs out of an egg carton.
2) Turn the heat on high until it comes to a boil (adding a bit of salt can speed up this process.
3) Put one of the eggs into the pot.
4) Let it cook for about 20 minutes.
5) Take the egg out and run it under cold water right away.
It is difficult to identify from two similar looking eggs which one is cooked and which one is raw. You do not want to make the mistake of cracking a raw one in hopes of eating a hard boiled egg, so there is a trick in figuring out which one is cooked and which is raw.
1) Spin each egg in turn on a plate. The egg that continues to spin for a longer time is the cooked one.
2) Now spin the eggs again, then quickly stop both of them. Let go of both the eggs. You will see that the cooked egg stays still but the raw egg starts to spin again.
What is the explanation
The contents of the egg have more inertia when they are raw, because they are in the form of a liquid. This inertia slows down the raw egg and that is why it stopped spinning before the cooked egg. In step 2, the liquid in the raw egg was still moving when you stopped both eggs, so that movement made the raw egg begin to spin again.
What is inertia?
Inertia is the sluggishness or apparent resistance of an object to change its state of motion. Mass is the measure of inertia.
For future teachers:
This experiment is a simple and fun one to do with younger kids. This would be a great way to teach kids the concept of inertia when studying weight or mass.
Plain paper (white printer paper)
2 books (per group)
at least 100 pennies or other small weights
Introduce the Activity:
Briefly discuss basics of bridges. (What are some famous ones? What is the purpose of bridges?)
1.Begin with a demonstration. Hold up one sheet of paper and ask students to predict how many pennies a bridge made out of this paper can hold. Place two books about 8 in. apart and place the paper flat across the two books. Ask for a volunteer to come up and test the predictions. When the bridge collapses with very few pennies, move the books closer and closer to test and see how much this single sheet of paper can hold. Point out that clearly one single sheet of paper will not make a very good bridge. Lead into the activity.
2.Ask: Now what can you guys do to make a bridge that will hold as many pennies as possible with one sheet of paper? (Group them and let them know they can use any method they want; cut, tear, paper clip, fold, etc.)
3.Whoever designs a bridge that can hold the most pennies will be rewarded for their ingenious work.
Changing the shape of a material can change the way it resists forces. Even though a piece of paper seems flexible and weak, it can be folded, rolled, twisted, or any other way altered to support a larger weight. Folding helps the paper resist bending forces created by the load of pennies on top of the bridge.
- Folding the paper into accordion style is most successful. Folding into an I-beam and paper-clipping the ends will be successful as well.
- Students will probably notice that the bridge can support more weight distributed along the bridge than at a single point.
Jeannie N. Ly
Title: Center of Gravity – On the Move
You probably have tried to balance a ruler or something like that on your finger before or a book on your head before. You might have noticed that the slightest change in movement causes the object to tilt and fall off. Once your find the exact spot where the object is balanced, you have found the objects center of gravity. The center of gravity is the exact spot of an object where there is an equal amount of weight on one side as there is on the opposite side. One way to find an object’s center of gravity is to move the object around on the tip of your finger until it balances nice and flat w/o tilting in any direction. The center of gravity can change when weight is added somewhere on the object.
3x5 index cards
pencil, pen, or marker
The Best of Wonder Science: Elementary Science Activity, Volume 1. Albany, New York: Delmar Publishers, 1997. (page 433 - 438)
CREATING LIGHT THROUGH FRICTION
BY ROSE LOPEZ
PURPOSE: Introduce students to some basic principles involved in the concept of energy. How energy can be transformed or converted from one form into another.
WHAT YOU NEED
WHAT TO DO
This experiment would be appropriate for sixth grade and above. This is excellent lesson to begin discussing how electrons and protons generate positive and negative charges within an atom. When the charged balloon touched the bulb, electrons moved from it to the bulb, causing the small sparks of light inside. In normal operation, the electrons to the bulb from the electrical power lines through a wire in the tube. This experiment generated enough energy through friction to light the bulb.
Objective: The students will learn about compression and tension by building their own structures. They will also learn how to make strong structures in compression and tension.
Materials: Gumdrops and round toothpicks
What is tension and compression?
Tension is a pulling force. It is when material stretches out.
Compression is a pushing force. It is materials get squashed.
Let’s Make Square and Cubes!!!
1. Start with 4 toothpicks and 4 gumdrops. Poke the toothpicks into the gumdrops to make a square with a gumdrop at each corner.
2. Poke another toothpick into the top of each gumdrop. Put a gumdrop on the top of each toothpick. Connect the gumdrops with toothpicks to make a cube. (A cube has a square on each side. It takes 8 gumdrops and 12 toothpicks.)
3. Use more toothpicks and gumdrops to keep building squares onto the sides of the cube. When your structure is about 6 inches tall or wide, try wiggling it from side to side. Does it feel solid, or does it feel kind of shaky?
2. Poke another toothpick into the top of each gumdrop. Bend those 3 toothpicks in toward the center. Poke all 3 toothpicks into one gumdrop to make a 3-sided pyramid. (A 3-sided pyramid has a triangle on each side. It takes 4 gumdrops and 6 toothpicks.)
3. Use more toothpicks and gumdrops to keep building triangles onto the sides of your pyramid. When your structure is about 6 inches tall or wide, try wiggling it from side to side. Does it feel solid, or does it feel kind of shaky?
You can make a very big structure out of squares and cubes, but it’ll be wiggly and will probably fall down. If you try to make a structure out of only triangles and pyramids, it won’t be wiggly, but you’ll probably run out of gumdrops and toothpicks before it gets very big. A 4-sided pyramid has a square on the bottom and triangles on all 4 sides. When you make a structure that uses both triangles and squares, you can make big structures that are less wiggly.
1. Build a square, then poke a toothpick into the top of each corner.
2. Bend all 4 toothpicks into the center and connect them with one gumdrop, to make a 4-sided pyramid.
3. What other ways can you use squares and triangles together? How big a structure can you make before you run out of gumdrops?
Even though your gumdrop structures are standing absolutely still, their parts are always pulling and on each other. Structures remain standing because some parts are being pulled or stretched and other parts are being pushed or squashed. The parts that are being pulled are in tension. The parts that are being squashed are in compression.
Sometimes you can figure out whether something is in tension or compression by imagining yourself in that object’s place. If you’re a brick and someone piles more bricks on you, you’ll feel squashed and you’re in compression. If you’re a rubber band and someone stretches you out you’ll feel being pulled apart and you’ll be in tension.
As you’ve probably already discovered, squares collapse easily under compression. Four toothpicks joined in a square tend to collapse by giving way at their weakest points. A square can fold into a diamond.
But if you make a toothpick triangle, the situation changes. The only way to change the angles of the triangle is by shortening one of the sides. So to make the triangle collapse you would have to push hard enough to break one of the toothpick.
If you want to, you can use your gumdrops and toothpicks to build some strong structures that are made by combining triangles and squares. The pattern you should try to get is one similar to some used in modern bridge design.
Area of Science: Physics
Grade Level: 4-6
Strategy: Alone or in pairs
Time: 15 – 20 min.
· One large paper or lightweight plastic cup (one from a fast food restaurant can be used).
· 1-2 pieces of string, 24 inches long.
· Paper clip
· Cellophane tape
· Smaller cup, covered with plastic wrap and is secured with a rubber band
· Other light ingredients
To discover how a plastic or paper cup affect sound vibrations.
· Start by pinching one end of the string tightly between the thumb and first finger of one hand. Slide your finger down the string, keeping the string very tight.
· How would you describe the sound? Now try plucking the string. What does this sound like?
· Now pull the string through the small hole on the bottom of the larger cup. It can be fastened with either a knot or being tied to a paper clip.
· Hold the cup in one hand and the string in the other. Now try plucking the string with a free finger. What do you hear?
· Make the string shorter, but keep the same tension, how does this affect the sound? Now make the string less taut, what sound is heard? Is it louder or softer than the string alone?
· Place the open end of the cup on a flat surface, like a table. Pluck the taut string. Put your ear on the table and pluck the string again. Lastly, hold the cup so the open end is pointed away from the flat surface. Compare the sound when you pluck the string.
· Wet the string of the Hilarious Honker, and slide your finder along the string. What sound is heard? Now try plucking the string.
· Why is the sound so much louder when the string is Wet? It’s because when the string is dry, air occupies the tiny spaces between the fibers.
· Take the second cup and make sure the plastic is tightly stretched across it. Place a pinch of salt on the plastic. Aim the Honker at the plastic covered surface and pluck the string. What happens?
· Move your finger along the string at different lengths, what happens?
· Replace with rice or other materials.
1. How does the size or weight of the items placed on the plastic-covered cup influence the effect of the sound waves?
2. How does the loudness of sound affect the movement of the items on the plastic-covered cup?
Physics Activity: Risers
Can the landing of spot of free-falling objects, which are
objects pulled only by gravity, be predicted?
2. 2-5 ounce (150cm) paper cups
3. Masking tape
4. Yardstick (meterstick)
5. Glass marble
1. Cut one cup down to a height of about 1 inch (2.5 cm)
2. Tape the short cup on one end of the stick.
3. Tape the taller cup to the stick about 4 inches (10 cm) away from the first cup.
4. Tape the other end of the yardstick (meter stick) to the door fame. The stick must be loose enough to be raised up and down easily.
5. Place the marble in the short cup.
6. Hold the stick with your fingers about 8 inches (20 cm from the end (just behind the taller cup).
7. Raise the cup end of the stick about 21 inches (53 cm) from the floor.
8. Allow the stick to fall to the floor. At the moment you release the stick. Note: The gentle push is very important. Repeat the experiment several times, each time changing the force of this push, until the following results are achived.
The marble moves out of the short cup and falls into the taller cup. If the marble did not fall into the cup, adjust the downward force on the stick. Push a little harder if the marble falls short of the cup; decrease the force of the push if the marble moves past the taller cup.
Gravity: is a force that pulls object on or near the earth’s surface toward its center. Free-falling objects are pulled straight down toward the earth’s center only by the force of gravity. The speed of the fall increases at a rate of 32 feet per second (9.8 m per sec) for every second of falling time. The push on the stick gives it a faster falling rate that the rate of free-falling objects. The faster-moving stick pulls the cup out from under the marble. The unsupported marble free-falls toward the floor. The path of the falling stick places the taller cup under the falling marble.
Aluminum foil Yes__ No__
Aluminum foil Yes__ No__
Clear plastic bottled-water bottle (1 liter)
Coffee filter (cone type)
Ball point pen
Blunt end scissors
Centrifugation requires that a mixture be spun around very quickly. If the centrifuge is set up correctly for a particular mixture, the different materials that make up the mixture will be able to separate themselves based on weight, size, shape and other factors.
Creating an Electric Circuit
How do light bulbs light up?
Electricity flows in paths called circuits. Imagine the way water flows from the spigot through a hose, this is similar to the way electricity flows through wires in circuits. A complete circuit is created when the electricity has a place to go or path to follow and can complete its circuit. In order for electricity to complete a circuit we need a battery, wire, and anything else we want to add to the circuit like a light bulb. When a bulb is added to our complete circuit it will light up.
Students will discover ways to make a light bulb light up using a battery, wire, and small light bulb.
Small light bulbs
The bulb will light up when it is part of a complete circuit of electricity. To allow this to happen, place the bulb on one end of the battery while touching the wire to the opposite end of the battery and simultaneously to the threaded base of the bulb. The students should be able to discover four different arrangements of battery, wire, and bulb that allow the bulb to light. Encourage different approaches and combinations of one, two, or three, of the objects they are dealing with. Many students may become frustrated; give them some clues, maybe showing the bulb lit up in your hand without allowing them to see the connection.
Four arrangements to light the bulb
1. The soldered tip of the bulb touching the positive end of the battery with one end of the wire touching the negative side of the battery and the other end touching the metal threaded base of the bulb.
2. Same as above, but placing the soldered tip of the light bulb this time on the negative end of the battery and touching one end of the wire to the positive end and the other end to the threaded base of the bulb.
3. Touch the metal threaded base of the bulb to the negative end of the battery running the wire from the positive end to the soldered tip of the bulb.
4. Same as #3 but placing the bulb’s threaded base on the positive end of the battery and running the wire from negative side to soldered tip of bulb.
Remind the students that the bulb must be included in the configuration of battery and wire. If the wire is touching both the positive and negative ends of the battery a short circuit will occur. A short circuit is created when the electricity is flowing too quickly within its circuit and has no outlet. Warn them of the danger and tell them that if their wires become hot they should put down their materials and call the teacher.
Grade Level 3-5
Purpose- To explain in an interesting way, how air affects objects, focusing on how quickly moving air exerts less pressure on objects than slower moving air. Students will also find out that planes fly because of this principle.
Introduction- 1. Ask if students have ever wondered how planes fly.
2. Explain that faster moving air pushes on objects less than slower moving air.
Demonstration- If students are having difficulty understanding air pressure, ask for two volunteers. Have one write quickly moving air on a piece of paper and tape it to their shirt. Have the other do the same but write slower moving air. Have the students stand on either side of you and put your palms out to either side. Ask the student with the quickly moving air to press against your hand. Then ask the student with the slowly moving air to press against your other hand a little more than the other student. You should move away from the slower moving air because it exerts move pressure.
Thin paper (I used wrapping paper)
Thicker stiff cardboard
A hole punch
A hairdryer (preferably with a cool setting)
Step 1. Cut a piece of paper about 6 by 4 inches. Choose one long side and punch a hole in both corners.
Step 2. Cut out a baseboard from stiff cardboard, 12by 4 inches. Fix straws on to thick cardboard using modeling clay so they fit through the holes in the paper.
Step 3. Use the thin paper to make a shape called an airfoil. Tape the paper over the first paper. The top of the paper should be curved up so it looks like an airplane wing.
Step 4. Aim the hairdryer at the wing. What happens? Ask the students if they can see how the shape of an airplane’s wing helps it to fly. Explain that the shape of the wing or airfoil, forces air to move more quickly over the wing so there is less pressure pushing down on the wing. The air that is moving slower under the wing exerts more pressure on the wing, pushing it upwards.
*Activity was taken from the Science Encyclopedia experiments by Jenny Vaughn, published by Dempsey Parr, 1999. Pages 32, 217. (I changed the experiment to suit a younger age group.
The oceans have always been salty, although most lakes and ponds are not salty. Do things float the same way in a lake or on the ocean?
Materials: two fresh raw eggs
two drinking glasses
Procedure: 1. Fill one glass with tap water.
2. Fill the other glass with the exact same amount of tap water and add five tablespoons of salt. Mix well.
3. Carefully crack open an egg and gently set it on the surface of the tap water. What happens to the egg?
4. Now set the other egg on the salty water. Does the egg do the same thing?
5. Weigh the two glasses, and compare them. Which weighs more?
The egg sinks in freshwater, but floats in salt water.
If you have the same amount of each, salt water weighs more than fresh water. There is more “stuff” in salt water than in the same amount of fresh water. We say salt water is denser than fresh water. The denser salt water can hold up the weight of an egg. But the fresh water doesn’t have enough “stuff” in it to support the same weight. Things float better in salt water than in fresh water because salt makes water heavier.
To learn about Pascal’s principle and buoyancy
Plastic bottle with top
Plastic Pen cap (that does not have a hole on top)
2 paper clips
1. Fill the plastic bottle with water.
2. Attach the rubber band around the plastic pen cap.
3. Unbend the two paper clips so that each end of the clip has a hook.
4. Hook both paper clips to the rubber band (on opposite side) so that they hand down towards the opening of the cap.
5. Stick the pen cap into the bottle so that the opening of the pen faces down and that the pen cap floats.
6. Put the lid on the bottle and tighten so that it does not leak any air.
7. Squeeze the sides of the bottle.
- What do you see?
- What is happening?
- How does this work? (It has to do with the balance of the forces of weight and buoyancy.)
- Most of us know what weight is -- the force that keeps us on the earth and stops us floating off into space, but what is buoyancy?
- What do you think causes the pen cap to sink when you squeeze the sides of the bottle?
By squeezing the bottle, you increase the pressure inside, thus forcing more water up into the pen cap. The added water in the cap increases its weight and causes the cap to sink.
The French scientist Blaise Pascal discovered the fact that pressure in a fluid is transmitted equally to all distances and in all directions. He formulated Pascal's law to describe the effects of pressure within a liquid.
Pascal’s Principle: A change in the pressure applied to an enclosed incompressible fluid is transmitted undiminished to every portion of the fluid to the walls of its container.
Stuck in a Rut
Objective: To identify the states of matter and their properties
1 cup of dry cornstarch
large bowl or pan
½ cup of water
** Notice what happens when the mixture is picked up with hands. It becomes a solid and then it’ll drip through fingers as a liquid. Why does this happen and how?
The answer to your curiosity:
The mixture is made up of tiny solid particles of cornstarch suspended in the water, known as colloid. When the mixture is banged on with a utensil or quickly squeezed, it freezes in place becoming a solid. The harder one pushes on it, the thicker it’ll become. When the mixture drips through one’s fingers, it becomes a liquid.
In 1700’s Issac Newton identified the properties of an ideal liquid. Water and other liquids that have properties are known as Newtonian fluids. A Non-Newtonian fluid is whose viscosity depends on the force applied. The mixture is an example of a Non-Newtonian fluid.
Other examples of Non-Newtonian fluids:
WILL A GRAPE FLOAT OR SINK?
Bouyancy and Density
Purpose: To teach children about bouyancy and Archimedes’ principle (that a floating object will displace a volume of fluid that has a weight equal to the weight of the object that is floating)
Age level: 4th or 5th grade
Will a grape float or sink in water? Will it float or sink in salt water?
What you will need:
1) Two clear glasses or plastic cups
2) Warm water( hot faucet water will suffice)
What to do:
1) Fill the glasses
2) Dissolve 3 teaspoons of salt in one glass. Stir into the water. (Using warm water just helps to dissolve it faster).
3) Drop one grape in each glass.
Which one sinks and which one floats?
4) Empty the glasses and start with fresh water.
5) Sink the grape into the glass.
6) Slowly add a little salt each time, until the grape rises to the surface.
Recall Archimedes’ principle: A floating object will displace a volume of fluid that has a weight equal to the weight of the object that is floating. If the object weighs more than its own volume in fluid, then it will sink….In other words, if an object is floating, that means it is less dense than the fluid, but if the object is denser than the fluid, it will sink.
The grape is denser than fresh water, so it sinks in the fresh water glass. But when you add salt into the water, than the water becomes denser than the grape, so the grape floats.
Also, the level at which the grape floats is determined by how dense the water is. So the more salt added to the water, the higher the grape will float.
Grade Level: 2nd
Purpose: Observe the properties of a variety of liquid materials in a small group (center). In this activity students will work in groups to investigate a number of different liquids to develop their understanding of the concept of a liquid.
Supplies: 1 set of 7 bottles (5 oz.) containing these liquids (fill bottles about half way):
· Plain water
· Colored water
· Corn syrup
· Cooking oil
· Liquid detergent
· Liquid hand soap
· Fabric softener or liquid starch
Procedure: Set up the center with the bottles. Show the students the bottles and tell them that their job is to work with a partner to find out as much as they can about the liquids in the bottles. Have the students tip, swirl, shake, roll, and investigate the liquids in the bottles. Make sure to tell the students not to open the bottles.
Give the students the following sheet to record their observations.
You may need to introduce and explain the meaning of the properties (colored, transparent, viscous, bubbly, translucent, and foamy) first before you let the students start the activity, may want to use visual cue cards for the students to refer to. Rotate group after 20 minutes. After all the student have had a chance to observe the liquids ask them some questions.
Possible extension: The vocabulary and language concepts associated with this activity can be developed formally (“A liquid that you can’t see through is a translucent liquid.”), or informally (“Timmy and Lisa said that the liquid was sticky, and other students thought it was slow and thick. Slow-moving, thick, sticky liquids are viscous. Can anyone else think of another liquid that is viscous?”) This can lead to an extension. You can develop a list of viscous liquids. You can also try to see if students can make up a list of the other properties. You can also have the students look through magazines and cut out pictures of different liquids that have the properties you have been discussing. Another extension that would be fun is to make oobleck. Put a box of cornstarch into a basin and add a cup of water. Add more water a bit at a time until the mixture just starts to become a liquid. Have students investigate its properties. Is it a liquid or a solid?
· whole homogenized milk
· pie plate
· any color food coloring you wish to use
· 1 tablespoon liquid Palmolive soap
Fill the pie plate about a half of inch with homogenized milk
Add numerous drops of food coloring on the surface of the milk. Do not stir it up!
Pour 1 tablespoon of Palmolive soap into the center of the pie pan. Wait a few minutes and watch what happens.
The soap will cause the milk and food coloring to mix together, creating swirls of colors in the milk. This will continue to happen for about five minutes.
When the food coloring is first added to the milk nothing happens. The food coloring just stays where you put it. When you add the soap, the soap spreads outs through the milk. This is caused because in homogenized milk the fat has been made so it’s very fine and evenly spread though the milk. The fat particles in milk have a negative charge. The soap particles are polar molecules, one end of the particle has a negative charge and the other has a positive charge. Since opposites attract, the positive end of the soap particle is attracted to the negatively charged parts of the fat particles in the milk. The soap particles link to the fat particles in the milk and spread the fat particles around. As the fat particles move, they move the food coloring as well. This movement causes the food coloring to mix with the milk, resulting in many swirls of color.
Magic Science By: Jim Wiese
Area of science: Physics Materials:
Grade level: 2nd-4th One cooked or hard-boiled egg
Time: 10 min. One raw egg
Overview: Galileo stated that in the absence of a force, a moving object will continue moving. The tendency of things to resist changes in motion was what Galileo called inertia. Newton refined Galileo’s idea and created his first law. The law of inertia states: Every object continues in its state of rest, or of uniform motion in a straight line, unless it is compelled to change that state by forces impressed upon it (Hewitt, 2002).
Conclusion: An eggs contents has more inertia when it is raw because the contents are in the form of a liquid. In step 1, the raw egg slowed and stopped first because of its inertia. This is why it stopped spinning before the cooked or hard-boiled egg. In step 2, when both eggs were stopped, the liquid contents of the raw egg were still in motion. This motion caused the raw egg to spin again.
Toying Around with Air Pressure
Air Pressure Rocket
You can make a fun toy using air pressure.
Air pressure can be compressed, and as air is compressed it has a higher and higher pressure. When the air is compressed the air will move from an area higher pressure to an area of lower pressure.
You can use these facts to make an air pressure rocket.
1) Cut a circle about 4 cm in diameter from you paper. Cut a slit to the center as then shape into a cone. Trim the point to make a small hole at the top.
2) Pull off the cotton from one end of a cotton swab. Push the cotton on the other end of the swab up through the hole so that the cone stays on the swab.
3) Place a straw into the empty bottle and hold it in place. Use the same hand to seal the opening of the bottle as much as possible. Place the rocket into the straw.
4) Point you rocket away from your face and away from any one else. Give the bottle a hard squeeze. YOUR ROCKET SHOULD ZOOM!
Try using a different bottle, straw set up, or rocket design to create an air pressure rocket goes the farthest.
Background Information: Newton’s Third Law of Motion states that every action is
accompanied by an opposite and equal reaction.
Grade Level: Second-Third
· Wooden pencil with eraser on one end
· Flexible soda straw
· Inflate and deflate the balloon to make sure the balloon will inflate properly.
· Tape the balloon to the end of the straw that does not bend. Secure it tightly,
but make sure that the balloon will inflate properly when you blow air through the straw.
· Bend the opposite end of the straw to a 90 degrees angle.
· Carefully pin the straw to the eraser end of the pencil. The pin should be
placed a couple of centimeters away from the balloon. Make certain that the straw is secured tightly to the eraser, but that the straw keeps its shape (not crushed).
· Blow into the straw and inflate the balloon. Hold the opening of the straw shut
with your fingers.
· Hold the pencil vertically with the straw and balloon on top. Let go of the
straw, and watch the pinwheel spin!
Discussion: The air leaving the balloon and travelling through the straw is the action.
The reaction is the force of the straw pushing against the air. Since the straw is bent at a 90 degrees angle, the straw and the balloon will spin around the pin.
Blowing up a Balloon without Wasting a Single Breath
Materials: plastic (1liter) bottle
Tissue paper (Multi-colors)
½ cup vinegar
1 Tablespoon baking soda
Directions: Each table will have their own supplies.
Place a tablespoon of baking soda onto the tissue paper.
1. Roll the tissue into a tube around the baking soda and twist closed the ends like a rolling pin.
2. Pour the vinegar into the bottle and drop the baking soda into the bottle.
3. Moving quickly, slip the neck of the balloon over the opening of the bottle and hold it in place.
4. The groups will slowly watch the balloon blow up without using a single breath.
Objective: Action, reaction, and then a result, when the tissue paper tears and the baking soda and vinegar melt, a reaction takes place, carbon dioxide, a gas is produced. The gas expands out of the bottle and into the balloon, and results in blowing the balloon up.
Key words for students:
Expand: To increase in size or volume.
Gas: a state of matter, such as air, that has no definite shape, but takes the shape of the container it is in.
Objective: Use visual demonstration to show class how the breaking of surface tension can be used to move objects across water.
What you need:
Questions to Ask the Class:
What happens to the boat when soap is added to the water?
The boat moves.
What causes the boat to move?
The soap breaks up the surface tension in the water behind the aluminum foil. The surface tension pulls the boat forward.
Give the class this example that they may have witnessed in their life:
Some pond insects can skim along the surface of the water in the same way. They're light enough that surface tension can hold them up, and they use their legs to break up the surface tension just enough to move.
This experiment was found at www.nyebabs.com
Grade Level: 4-5
Suggested Time: 15 minutes
Þ Find out whether an egg will float in different solutions.
Þ Find out how density affects buoyancy.
Definition of Concepts:
Þ Buoyancy--the apparent loss of weight experienced by objects
submerged in a liquid/Archimede’s Principle --An immersed
body is buoyed up by a force equal to the weight of the fluid it
Þ Density--(Mass/Volume=Density)--The masses of the atoms and
spacing between them determine the density of materials.
Þ Will the egg sink or float in regular water?
Þ Will the egg sink or float in a water and salt solution?
Þ Will the egg sink or float in a water and flour solution?
· 1 uncooked egg
· 3 plastic cups
· 1 spoon
· 2 tablespoons of salt
· 2 tablespoons of flour
1. Carefully place the egg into a cup with water. Does the egg sink or float?
2. Remove the egg from the cup.
3. Pour two tablespoons of salt into the second cup of water and
stir with a spoon.
4. Carefully place the egg into the water/salt solution. Does the egg sink or float?
5. Remove the egg from the cup.
6. Pour two tablespoons of flour into the third cup of water and stir
with a spoon.
7. Carefully place the egg into the water/flour solution. Does the egg sink or float?
Why did the egg sink in the cup with water, and in the cup with water and flour? It sank because the egg is denser than the water, and it is denser than the water and flour solution. To further exemplify, the weight of the water displaced by the egg is less than the weight of the egg itself. Likewise, the weight of the water and flour solution displaced by the egg is less than the weight of the egg itself. In turn, the buoyant force was not able to make the egg float.
Why did the egg float in the cup with water and salt? It floated because the water and salt solution is denser than the egg. To further exemplify, the weight of the water and salt solution displaced by the egg is more than the weight of the egg itself. In this case, the buoyant force acting on the egg was able to make the egg float.
Objective: The students will discover that liquids can have different densities. They will also be able to define density of liquids.
Materials: In groups of 2-4 students, grades 4-6
One clear container for each group( an average sized water bottle will do)
Three small clear plastic drinking cups for each group
1/3 cup measuring cup
syrup (regular maple or corn syrup)
plastic pieces (checker board pieces work very well)
Before you begin the activity have the students identify the properties of these liquids. Have the students measure out 1/3 cup of each liquid in each of the three clear plastic drinking cups. Do all three liquids take up the same amount of space? Do they have the same mass or weight? How can we find out? Have the student lift and feel. Next have them use the balance to determine the mass of each liquid. Record the findings on the board.
The students will notice that even though the liquids occupied the same space, their masses are different. The syrup had a larger mass than the water and the water has a larger mass than the oil. When liquids occupy the same amount of space but they have varying masses, they are said to be more or less dense than the other.
Now what do you think will happen if the liquids were all in the same jar? Allow the students to make predictions on what would happen.
Have the students first pour the 1/3 cup of syrup and pour it into the jar.
Next pour 1/3 cup of oil on top of the syrup.
Finally pour 1/3 cup of water on top of the oil.
What happens? Was it what you thought would happen?
Extension Activity: What would happen if we added objects to the layered liquids? Allow the students to make predictions of whether the objects will float or sink. If they predict it to float, on which layer do they think the object will float?
Just for thought: Do you think it makes a difference what temperature you have the water?
Can You Filter the Dirt Out of Water
5th grade level
Box of books
Piece of Yarn (long enough to reach from bowl to bowl)
1. Fill a bowl half full of water
2. Wet a piece of yarn
3. Mix some dirt into bowl of water
4. Raise bowl up on stack of books
5. Set empty bowl on table lower than bowl containing dirty water.
Water seeps through tiny spaces in yarn and moves into empty bowl separating water from dirt.
Study of capillarity in Conceptual Physics pg. 261: water will rise higher in a narrow space than in a wider tube thru capillary action. This can be visualized by a paint brush or placing long hair in a sink of water. In this experiment capillary action causes water to go through tiny spaces of the yarn by the attraction between the water and the threads in the yarn. This attraction is called adhesion. As the water moves through the yarn suspended soil particles are left behind.
Explain how capillary action is used in plant growth?
Plants received water from the ground through their roots and carries nourishment through the vascular system to higher branches.
To show students the affect of air pressure
The student will be able to identify air pressure and how it affects objects.
Cups (plastic or glass)
Fill the cup with water making sure that the cup is somewhat overflowing. Then proceed to place the postcard on top of the cup. When the postcard seems secure, flip the cup over (upside down). The result should be that the post card remains in position and keeps the water from coming out of cup.
Children should be able to understand the concept of air pressure. Students should be able to be aware of the fact that air pushes in all directions. For this particular experiment, the air pushing upward from the ground is pushing the postcard tightly against the cup. The pressure that is being exerted by the air is more powerful than the pressure of the water attempting to push itself out of the cup resulting in why the water is incapable to break the postcard’s force.
Grade Level: 4-5
Objective: To introduce students to the concepts of friction and how different surface areas contain more friction (against a moving marble). This activity will help students with their math skills- addition, division, and measuring.
Materials: 2 rulers, yardstick or meter stick or measuring tape, one marble, a book (3-4 cm), wax paper (60 cm), sand paper sheets taped together (30 cm), bath towel, aluminum foil (30 cm).
Introduction: A force describes an action or interaction between two things. There are several kinds of interactions or forces. One is friction. Whenever two materials rub against one another, there is a force between them called friction. Can anyone think of an example of friction in real life, what do you know that rubs together? What about when the tires of a speeding car rub against the road, when a towel rubs against your wet skin, or when air rubs against a falling apple. An easy example is to take your book and briefly push it across the tabletop. What happened? Your book should have come to a stop; can you guess why this is? The book will slow down as it slides and we know that some force must be causing this slowing because the law of inertia says that the speed would be unchanging if there were no force on the book. The force that slows the book must result from the contact between the book and the tabletop, it must be the friction between the tabletop and the bottom of the book. Friction is the resistive force by a surface of an object sliding across that surface; Friction can slow things down or make things difficult to move so sometimes we don’t want friction. But sometimes we do. Friction can also help to get things moving or stop moving like the brakes of our bikes. In this activity, “Science Friction,” you can compare the amount of friction between a marble and different surfaces like wax paper, sand paper, towel, and foil.
1. Prepare your materials on your desks, or a long tabletop. Make an inclined track by leaning two rulers next to each other on a book. Be sure there is plenty of flat space at the end of the track.
2. Place the length of the wax paper at the end of the track. Release a marble (don’t push it!) from a point near the top of the track and watch as it rolls down the track and along the wax paper. How did the speed of the marble change as it roller across the wax paper? How far did it go?
3. Measure the distance from the bottom of the track to the place where the marble stopped, and write it in the chart. Roll the marble down the track a couple of times, measuring the distance the marble travels each time. Be sure to release the marble from the same place each time. Write your measurements in the chart.
4. Add your distance measurements together and divide this answer by three to find the average distance the marble rolled. When scientists do experiments, they always make several measurements like this and then average the results. Why is it a good idea to do this?
5. Do you think the distance the marble travels will change if you replace the wax paper with a towel? Try it and see? Repeat three times, writing down and averaging your distance measurements like you did before. What is the name of the force that stops the marble? All forces have a direction. What is the direction of this force?
6. Place the other materials such as the sandpaper or some aluminum foil that has been crumpled and flattened out at the end of the track. With which material is the force of friction greatest? Which material is the force of friction the least?
Wrap-up: Now for our marble- our marble is moving to the right, is there a force to the right? No. Air drag is doing the force in what direction? The left. What can we conclude that the weight is due to? The Earth’s pull.
Things to keep in mind: With no friction, objects would accelerate forever once an agent acted on them. With friction there is no acceleration. Friction is always the opposite of motion.
Source: Wonder Science Book Volume I.
Juli Ann Garduque
Grade level = 3rd
To find out what colors are mixed to make the color black.
Most nonpermanent black markers are made up of colored inks and water. The water dilutes the black ink leaving the colored pigments that make up the black onto the coffee filter. When dried out, the left over pigments stay on the paper telling us what colors were used to make the black ink.
In this experiment, you’re using a technique called chromatography. Chromatography can be broken up into the Greek words chroma and graph which means “color writing”. This technique was first introduced by the Russian botanist Mikhail Tsvet in 1910. He used chromatography to separate the pigments that made up plant dyes.
There are many different types of chromatography. In all of them, a gas or liquid (like the water in your experiment) flows through a stationary substance (like your coffee filter). Since different ingredients in a mixture are carried along at different rates, they end up in different places. By examining where all the ingredients ended up, scientists can figure out what was combined to make the mixture.
Why does mixing many colors of ink make black?
Ink and paint get their colors by absorbing some of the colors in white light and reflecting others. Green ink looks green because it reflects the green part of white light and absorbs all the other colors. Red ink looks red because it reflects red light and absorbs all the other colors. When you mix green, red, blue, and yellow ink, each ink that you add absorbs more light. That leaves less light to reflect to your eyes. Since the mixture absorbs light of many colors and reflects very little, you end up with black. The colors that make up black ink are red, green, blue, and yellow.
Sara Pernillo Vargas
Flying Paper Clips
Can paper clips float in the air?
The paper clip stays in the air because the magnet attracts it.
One paper clip
A piece of tread
1. Tie a thread to the paper clip.
2. Tape the other end of the thread to the table.
3. Hold the magnet just above the paper clip so it appears to float at the end
of the tread.
The magnetic attraction goes beyond the magnet so the paper clip doesn’t have to touch the magnet to attract it.
Magnet: a body having the property of attracting iron and producing a magnetic field external to itself
Magnetic field: the portion of space near a magnetic body or a current-carrying body in which the magnetic forces due to the body or current can be detected
· 2 FLASHLIGHT BATTERIES
· 1 FLASHLIGHT BULB
· MASKING TAPE
· ALUMINIUM FOIL
· 1 PIECE OF PAPER
1. TO SHOW THAT METAL IS A BETTER CONDUCTOR THAN PAPER.
2. TO INTRODUCE TERMS- INDUCTORS & CONDUCTORS.
3. INTRODUCE STUDENTS TO SOME PROPERTIES OF METALS.
4. TO DEMONSTRATE THAT ELECTRICITY TRAVELS IN A CURRENCY, SIMILAR TO WATER.
1. Tape the two batteries together using the masking tape. Positive end of one battery connected to the negative end of the other battery.
2. Cut two strips of aluminum foil about .5 cm wide and 18 cm long, and then cut the paper into strips the same size.
3. Tape one end of each paper strip to opposite ends of the batteries.
4. Wrap the free end of one of the paper strips around the metal casing of the light bulb. Take the other end and touch the bottom of the light bulb. Does it light? Is the paper a conductor or an inductor?
5. Repeat the process using the aluminum strips. Does the light bulb light? Is the aluminum foil and inductor or a conductor?
This is a great experiment for grades fourth and above.