# Inertia – Tablecloth Trick & Egg Drop

Inertia – Tablecloth Trick & Egg Drop

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Physicists study matter - all of the ”stuff” in the universe and how that “stuff” moves. One of the most famous physicists of all time was Sir Isaac NewtonSir Isaac is most famous for explaining gravity, a concept we are so familiar with now it seems obvious to us. He is also famous for explaining how stuff moves, his Three Laws of Motion. Today we are going to look at Newton’s First Law of Motion called Inertia.

Newton’s First Law of Motion (Inertia): A still object will stay still unless a force pushes or pulls it. A moving object will stay moving unless a force pushes or pulls it.

Gravity and friction are forces that constantly push and pull the “stuff” on earth. So, when we roll a ball, it slowly comes to a stop. On the moon, where there is less gravity and friction, “stuff” floats, and keeps floating.

In this video, an astronomer demonstrates Inertia:

Here are some good websites that explain inertia or show you experiments to try:

You can try two Inertia Experiments at home: The Tablecloth Trick and The Egg Drop. The two videos will give you good directions.

For The Tablecloth Trick You Will Need:

Drinking Glasses (non-breakable!)
a Plate (non-breakable!)
a Piece of Frabric or Tablecloth with NO HEM
Water
a Table

The items on the tablecloth - the drinking glasses full of water and the plate - are not moving. According to Newton’s law they should stay still unless a force pushes or pulls them. When you pull the tablecloth out from under them friction is a force that causes the plate to move just a little, but since the cloth is slippery it pulls right out, leaving the plate and glasses full of water in place.

For The Egg Drop You Will Need:

Egg
Toilet Paper Tube
Pie Pan
Drinking Glass
Water

In The Egg Drop the egg is not in motion, it is at rest. According to Newton’s law it should stay that way. When you slap the pan away you apply force to the pan and it moves, knocking out the toilet paper tube also, but you did not hit the egg so it stays in place. It DOES drop though, since the support of the toilet paper tube is gone gravity acts on the egg and pulls it toward the earth.

In this video see how seat belts and head rests in cars help save lives by using Newton’s First Law of Motion (Inertia):

Here are some books that will help you understand inertia, learn about Sir Isaac Newton or get directions for inertia science experiments:

• Gizmos and Gadgets – Inertia Zoom Ball (pages 9-10); Inertia Coin Magic (page 12).
• Google Preview: Naked Eggs and Flying Potatoes: The Egg Drop  (Pages?)

Words to Know:

Physics – The study of matter and motion.
Physicist – A person who studies matter and motion.
Sir Isaac Newton – A physicist from the 16/17th Century who figured out gravity and three laws of motion.
Laws of Motion – Rules that explain how matter, or “stuff” moves on earth.
Inertia – Newton’s First Law of Motion. Every object persists in its state of rest or uniform motion in a straight line unless it is compelled to change that state by forces impressed upon it. SIMPLY: A still object will stay still unless a force pushes or pulls it. A moving object will stay moving unless a force pushes or pulls it.

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# Saturation – Growing Crystals

Saturation – Growing Crystals

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Crystals are made when a substance has atoms or molecules that form in a very organized, repeating 3D pattern. Usually when we think of crystals we think of some well-known gemstones like diamonds or rubies, but there are some very common crystals too. Sugar, ice, snowflakes, salt…all of these are crystals. You can make your own crystalsgrow.

You will need:

• 2 Glasses or Jars
• 1 Plate
• 1 Spoon
• 2 Paper Clips
• Hot Tap Water
• Piece of Yarn or Cotton String, about 6 inches long
• Baking Soda

Fill each glass with water. Add 2 tablespoons of baking soda to each glass. Stir the mixture. If all of the baking soda dissolves, add a little more baking soda and stir. Add baking soda until the water can’t dissolve it anymore, the mixture is saturated. That means the water is holding as much of the baking soda as it can. You can add a few drops of food coloring to each glass to make the crystals colorful. Tie a paper clip to each end of the piece of yarn or string. Drop one paperclip into each glass letting the string dangle in a smile shape in between the glasses but not touching the plate. Watch the string over the next few days to see the crystals form along the string.

The picture on the right shows you what the baking soda crystals will look like after a few days. As the days go by and the water in the baking soda solution evaporates, the level of the water will go down. Make sure the end of the string with the paper clip on it stays submerged in the baking soda water in the glass.

Science Experiment Idea

Grow more than one kind of crystal. Use salt, sugar, and baking soda. Keep a chart as you observe how the crystals grow over the next few weeks. Which one do you think will grow the biggest? Which one will form the fastest?

Here is a video that shows you some super fast crystal growing:

Here are some books and websites that give you ideas for making crystals. You can grow crystals using salt, sugar, baking soda and many other substances.

Words to Know:
Crystal
– A solid whose atoms or molecules are arranged in a 3-dimensional repeating pattern. Examples: A snowflake, a sugar crystal, a diamond.
Crystallized – The process of crystal growth or crystal formation.
Dissolve – To mix two substances together and have the molecules of one substance spread out between the molecules of the other substance.
Saturated - When a liquid is holding as much of a solid as it can. It has dissolved all of the solid it can hold.

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# Chemical Bond – Kool Aid Tie Dye

Chemical Bond – Kool Aid Tie Dye

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When the atoms in different kinds of molecules come together they can form a chemical bond. This happens when some of the electrons from each kind of atom have an attraction to each other so they stick together. In this experiment you will be able to see a chemical bond. Dye made from kool aid and vinegar will make a bond, or “stick” to the fabric of a cotton t-shirt.

Some chemical bonds are strong and the two substances really stick to each other. Some chemical bonds are weak. The chemical bond between kool-aid/vinegar and the t-shirt is weak. The vinegar added to the kool-aid is called a mordant. A mordant is a substance that helps dye stick to fabric. The kool-aid/vinegar dye will make a weak chemical bond so your shirt will fade over time. The chemical bond in a permanent dye is strong – shirts dyed with this kind of dye stay bright for a long time. After you practice with kool-aid, THEN try a more permanent dye.

NOTE: Even though the kool-aid/vinegar dye is weak…you should still do this OUTSIDE! The kool-aid/vinegar dye will stay on your fingers and especially your fingernails for a day or so unless you wash them really good. (So…it would also stay for awhile on your clothes or the carpet in your house!) My dog licked the bowl of blue kool-aid/vinegar dye and it turned her tongue blue. She also splashed some on her foot. The next day her tongue was not blue anymore put the fur on her paw was!

You Will Need:

• T-shirt/Sock/Towel – Anything Made From Cotton
• Kool Aid Packets
• Several Bowls
• Spoon
• Water
• Vinegar
• Measuring Cups
• Rubber Bands

Science Experiment Idea: Try dying three identical shirts with kool aid using different amounts of vinegar. Which mixture made the darkest color? Which mixture lasted the longest?

Website that give you good directions for Kool Aid Tie Dye:

Words to Know:

Atoms - The smallest, most basic unit of matter. An atom is made up of a nucleus surrounded by electrons.
Molecules - At least two atoms held together by a chemical bond.
Chemical Bonds - An attraction between atoms so that the atoms stick together. The attraction happens because the two kinds of atoms have opposite charges. Some kinds of chemical bonds are really strong and some are weak.
Mordant – a substance that is used to set dyes on fabric. It helps make the chemical link or bond so that the dye will not wash out.

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# Chemical Reaction – Exploding Ziploc

Chemical Reaction – Exploding Ziploc

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In today’s experiment you will be able to watch a chemical reaction. In this experiment vinegar (a substance) and baking soda (a substance) will mix together. When mixed together the molecules of the two substances will re-arrange, or change, to make new substances.

Vinegar has acetic acid in it. The chemical name for baking soda is sodium bicarbonate. When you mix the two together you get sodium acetate and water. You also get carbon dioxide, which is a gas. The bag puffs up because carbon dioxide is a gas and takes up a lot of space. Eventually the bag isn’t big enough to hold all that carbon dioxide gas so it explodes.

You Will Need:

• Measuring Cups and Spoons
• Baking soda
• Vinegar
• Snack size ziploc bag
• Quart size ziploc bag

Measure one tablespoon of  baking soda into a quart size ziploc bag. Measure 1/2 cup of vinegar into the snack size ziploc bag and zip the bag closed. Put the snack size ziploc bag full of vinegar into the quart size ziploc bag with the baking soda in it. Get as much air as possible out of the quart size bag before zipping it closed. Go outside! Stand in the middle of your yard. Grip the snack size ziploc bag from the outside of the quart size bag and pull it open. As soon as the vinegar starts to mix with the baking soda drop the bags into the grass and watch what happens.

If your bag inflates, but does not explode, try increasing the amount of baking soda and vinegar. If you do this, be sure to drop the bag quickly and take several steps away after you mix the two substances together – when the bag explodes it splashes vinegar everywhere…which does not feel good in your eyes. See the dog’s nose and eyes? Too close! And…it goes without saying to do this OUTSIDE.

Websites that give you good directions for making exploding ziplocs.

Here are some books that give you good directions for making exploding ziplocs or other demonstrations using vinegar and baking soda to make a chemical reaction.

• Google Preview: Naked Eggs and Flying Potatoes: Make a CO2 Sandwich  (Pages 44-47)
• Google Preview: Science Experiments That Fizz and Bubble: Personal Puffer (Pages 14-15)
• Google Preview: Science Experiments That Fizz and Bubble: Soda Shooter (Pages 26-29)
• Mythbusters Science Fair Book: Make Your Own Water Rocket (Pages 108-109)
• Google Preview: Science Experiments That Implode and Explode: Plastic Bag Bomb (Pages 12-13)

Words to Know:

Chemical Reaction – When a substances or substances is changed into a new substance.

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# Hydrologic (Water) Cycle: Make a Terrarium

Hydrologic (Water) Cycle: Make a Terrarium

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All of the water on the earth is in constant motion. Water falls to the earth as rain and then evaporates back up into the air making clouds. Then the water falls back down to earth again as rain. This cycle is call the hydrologic or water cycle.

To see how the hydrologic cycle works you can make your own little model of the earth in a terrarium. A terrarium is a little garden inside a sealed container.

What You Need:

• a Clear Plastic or Glass Container With a Lid
• Stones
• Soil
• Plants
• Water
• Little Toys for Decoration (optional)

When you poor water into your terrarium that is the beginning of the water cycle. You essentially have made it rain in your little glass world. When you set your terrarium in the sun the water inside the terrarium heats up and turns into water vapor in the air. This is called evaporation. When the water cools back down, it turns back into a liquid.  You will see condensation – water droplets – sticking to the lid of your terrarium. If the drops get large enough, they will roll down the sides of the container or fall from the lid – rain!

The close-up on the left shows the condensation that began to form on the inside of the jar after only 1 hour sitting in the sun.

If there is too much water just open the lid and let some of the water evaporate. If your plants look wilted or dry, try adding a little more water. It might take some trial and error to get the amount of water needed just right.

Here are some websites and books that give you step by step directions for making a terrarium:

Science Experiment Idea: Make three identical terrariums. You have to use the same kind of container, the same amount of soil & the same plants. Make your variable (the thing you are going to test) the amount of water you put into the terrariums. Measure a different amount of water into each terrarium. Close the lids and watch the terrariums over several days to see which amount of water made the best environment for your plants. A terrarium with too little water will have dry plants. A terrarium with too much water will have plants with yellow leaves and maybe even mold growing on the soil!

Words to Know:

Terrarium - A clear container with a lid used for growing plants.
Hydrologic (Water) Cycle – The movement of water from liquid to gas (evaporation) and from gas to liquid (precipitation).
Condensation – Water vapor cooling off and changing to liquid water.
Evaporation - Liquid water heating up and changing to water vapor.
Precipitation – Rain, snow, or hail.

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