Density Experiment

Density refers to the amount of stuff there is in a given space. Different things have different densities. For example, a cup of water has more stuff in it than a cup of oil. The water is denser. A marble and a ball of the exact same size are made of different amounts of stuff – they have different densities. Do you think the less dense oil will sink in or float on the denser water? Which is denser, the marble or the ball? How can you tell?

Problem:

How do liquids of various densities interact with each other?

Materials:

• Measuring cup
• Clear glass jar (labels removed)
• ½ cup water
• Food coloring
• ½ cup corn syrup
• ½ cup vegetable oil
• Marble
• Small rubber ball of approximately the same size as marble
• Circle of carrot, mini marshmallow, other small objects

Procedure

1. Pour the water into the jar.
2. Color it with food coloring.
3. Pour the corn syrup into the jar. What happens?
4. Carefully pour the oil into the jar. What happens?
5. Drop the marble into the jar. Does it float? Sink?
6. Drop the ball into the jar. Does it float? Sink?
7. Continue dropping objects into the jar and observing what happens.
8. What can you tell about the densities of the liquids and the objects?

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Does the Amount of Air Inside the Ball Affect How Far It Goes?

Objectives

To determine whether the amount of air in a soccer ball will affect how far it goes when kicked.

 

Materials and Equipment required

• Soccer ball
• Ball pump
• Ball pressure gauge
• Tape measure meter or yardstick
• Inflation needle
• Glycerin oil
• Roll of gym floor tape
• Marker
• Pen
• Graph paper
• Data chart

Introduction

This soccer science fair project serves to acquaint students with basic information on how the amount of air in a soccer ball can affect the distance it travels when kicked with a consistent force. The greater the air pressure in the ball, the farther it will travel when a force is applied. In the process of conducting the research, the student will learn that atmospheric pressure may also affect how far the ball will travel. The student will learn about the relationship between air pressure and friction: the lower the friction, the farther the ball will go. The student will learn about concepts like air pressure, gravitational force, compression and expansion of air molecules, potential energy and kinetic energy.
This science fair experiment also serves to acquaint students with the essential processes of scientific inquiry such as using a control, of identifying dependent and independent variables, collecting data, presenting data, and making good judgments about the validity and reliability of their findings.

Research Terms

• air
• friction
• forces
• air pressure
• compression of air molecules
• expansion of air molecules
• gravitational force
• energy
• kinetic energy
• pressure gauge
• air pump

Research Questions

• How do we measure air pressure?
• How much air pressure is there at sea level?
• How is air pressure inside the ball related to the distance the ball will travel?
• What happens to the air pressure inside the ball when it is kicked?
• Will the atmospheric pressure affect the distance the ball will travel?
• Does friction affect the distance the ball will travel?

Terms, Concepts and Questions to Start Background Research:

• What is a control? A control is the variable that is not changed in the experiment.
• What purpose does a control serve? It is used to determine what the variable changed.
• What are variables? Variables are factors that can be changed in an experiment.
• What is an independent variable? The independent variable is the one that is changed in the experiment.
• What is a dependent variable? The dependent variable is the one that changes as a result of the change in the independent variable.

Experimental Procedure

1. State the problem you are going to investigate in this science fair project.
2. Create and reproduce the data sheets you will use to record your observations.
3. Gather all your materials.
4. Select a helper (another student or a parent) to assist you in gathering the data.
5. Use the gym floor tape and mark the path along which you will kick the ball.
6. Select three air pressure levels for the ball, designating them as low, medium and high. Using the pressure gauge, double check the pressure in the soccer ball each time you change the pressure. Caution: When kicking the ball, try to kick with the same force each time. Have your partner mark the spot where the ball lands each time. Then, measure the distance and record the data in your chart. Repeat the procedure 3 times at each pressure level and then average and record the results for each level.
7. Make a line graph of the data, recording differences in pressure on the Y axis and the distance travelled on the X axis.
8. Record your conclusion and prepare your report. Include all of the following: a clear statement of the problem, your hypothesis, and a list of the materials used. Include any safety precautions taken. Describe the procedures used. Include all the data that were gathered, including all charts and graphs. For dramatic value, you may include photos of the materials used or of you in the process of conducting this investigation. Include a bibliography of sources you used. You may wish to assess what you did and describe what you would do differently if you were to do this project again. You may wish to expand this research next year. What other experiments might you use to investigate the physics of a soccer ball?

Charting and or Graphing Data

In each section of the experiment, use charts to display the obtained data such the following sample:

Chart #1 : Observations: How far did the ball go?

Pressure in soccer ball in PSI	Distance Travelled in cm.
High #1
High #2
High#3
Medium #1
Medium #2
Medium#3
Low #1
Low#2
Low#3

Chart #2: Average Data

Pressure	Averages
High PSI
Medium PSI
Low PSI

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Can You Cook Using Only Sunlight?

Grade Level: 7th to 11th; Type: Meteorology, Physics

Objective:

Bake cookies with an oven that collects sunlight and traps heat.

• How can I cook using just sunlight?

Make an oven that collects sunlight and traps the shorter wavelengths (heat!) inside the same way greenhouse gases in our atmosphere trap them, and bake some cookies!

Materials:

• Two cardboard boxes: one must fit completely inside the other with about an inch or two to spare, and the outer one must have flaps (or you can create and attach some)
• Roll of aluminum foil
• Masking tape
• Four 12-inch pieces of string
• Eight beads or pieces of macaroni
• Pencil
• Piece of black construction paper
• Scissors
• Scrunched-up shredded paper
• Piece of glass, large enough to completely cover the smaller box but small enough to fit inside the larger one
• Cooking thermometer
• Small cookie sheet or pie tin (must fit inside smaller box; make your own with some of the foil if necessary)
• Prepared cookie dough (commercial or homemade) that bakes at 350° or under warm, sunny day

Experimental Procedure

1. Cover the insides of the flaps of the larger box with aluminum foil, with the shiny side facing out; tape the foil in place. Use the pencil to poke small holes in the edges of the flaps.
2. Tie a bead to one end of one of the pieces of string, string it through one of the holes in one of the flaps so that the bead ends up on the outside of the flap, string it through the hole in the next flap over from the inner side to the outer, and tie another bead to this end of the string. Repeat so that all four flaps are connected together with the strings.
3. Line the entire inside of the smaller box with foil, shiny side out, taping it in place.
4. Cut the piece of construction paper so that it fits neatly inside the smaller box; tape it inside the bottom of the box.
5. Put enough shredded paper inside the larger box so that when you rest the smaller box on it, the opening is just barely below the opening of the big box.
6. Center the little box and pack the space between the walls of the big box and the walls of the little box with more shredded paper.
7. Put the cooking thermometer and some of the cookies on the baking sheet (you may need to grease it first: check the instructions/recipe) and set it inside the inner box; cover the inner box with the pane of glass. Your solar oven is ready to go!
8. Take the oven outside and set it in a bright, sunny spot where it won’t be disturbed. Turn it so that the sun shines directly into it; if the sun isn’t pretty close to directly overhead, you might want to put something under one side of the box to tip it to face the sun. Use the strings to adjust the flaps so that as much sunlight as possible is reflected into the inside of the oven.
9. Now you wait. I hope you brought a good book! Depending on the time of day and how warm it is outside, you may need to turn the oven or even move it to a new spot so that it gets as much sunlight in it as possible.
10. Keep an eye on the cooking thermometer. You’ll notice that it gets much hotter inside the oven than it is outside. That’s partly because the aluminum foil is focusing the solar radiation, and partly because the glass is acting like a layer of greenhouse gases: like them, it’s clear, but some of the shorter wavelengths will bounce off of it and tend to stay inside the oven, making things hotter and hotter inside. It may get as hot as 350° Fahrenheit in there!
11. When the cookies look like they’re about done (they’ll probably be browning around the edges and won’t be shiny anymore), or when the thermometer reads a temperature higher than they’re supposed to cook at, whichever comes first, take the glass off and let the inside of the oven cool for a few minutes. When the cookie sheet isn’t too hot to touch anymore, lift it out and try a cookie!

Terms/Concepts: solar radiation, greenhouse gases

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Crystal Fudge

Grade Level: 8th to 12th; Type: Geology

Objective:

Find out what happens when the fudge crystallizes at different temperatures.

Research Question:

• Why do some rocks that are made out of the same minerals have different-sized crystals in them?
• What effect will faster vs. slower cooling have on the formation of crystals?

Fudge is one of very few desserts people make at home that is actually crystalline, or made out of crystals. This gives us a fun, tasty way to explore the process of crytalization.

Materials:

• Two bread pans (disposable 8” pie tins will also work)
• Butter to coat pans, or waxed paper
• Large saucepan (3-4 quart)
• Wooden spoon
• Candy thermometer
• Pastry brush
• Stove
• Refrigerator
• 3oz. unsweetened chocolate
• 3c sugar
• 1c warm half-and-half or evaporated whole milk
• 1T corn syrup ¼t salt
• 3T butter
• 2t vanilla extract
• 1c mix-ins of your choice: nuts, mini marshmallows, dried fruit… (optional)
• Magnifying glass

Experimental Procedure

• Butter the pans or line them with the waxed paper.
• Mix the chocolate, sugar, salt, half-and-half, and corn syrup over medium-low heat. Keep stirring until the chocolate is melted and the fudge begins to boil. Note: the fudge is extremely hot at this point, handle with care!
• As soon as the fudge begins to boil, stop stirring and put the candy thermometer in. Clip it to the edge of the pot, making sure the tip isn’t touching the bottom.
• Let the fudge cook without any stirring until it reaches the soft-ball stage, around 237 degrees.
• While the fudge cooks, dip the pastry brush in a little warm water and use it to carefully wash any sugar/chocolate/whatever off the sides of the pot.
• Take the fudge off of the burner and let it cool, undisturbed, until it’s 150 degress.
• Add the vanilla and butter and keep stirring until the surface of the fudge starts to get dull. This can take a long time, but you need to keep stirring! Maybe you can get a partner to help.
• Once the fudge has begun to dull, stir in your add-ins, a quarter-cup at a time, if you’re using any. Make sure they’re at room temperature or a little warmer if possible.
• Spoon half of the fudge into each pan. Put one pan in the refrigerator and leave the other one out at room temperature. Allow both of them to cool completely.
• Cut each panful of fudge into one-inch cubes. Pick up a cube from each pan and examine them closely. Use your eyes and the magnifying glass: do you see any differences in texture? Use your tongue: does one seem more smooth and waxy while the other is more grainy? Is there a difference in flavor? The fudge that cooled more slowly, at room temperature, should be grainier and have noticeable sugar crystals in it. This is like a plutonic igneous rock that has cooled and solidified slowly, under the surface, like granite. The one that cooled more quickly, in the refrigerator, should be smoother and have much smaller crystals, probably too small for you to see even with the magnifying glass. This is like a volcanic igneous rock that cooled quickly above the earth’s surface, like obsidian.
• Now offer samples of each to your family and friends so they can decide which they like best!

Terms/Concepts: igneous rock; crystallography, crystal formation

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