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Gravity is the force that pulls objects toward the center of the Earth. Gravity can make things fall down but it can also help hold things in place. You probably have some games at home the show you a lot about the power of gravity. One of those games is Jenga – that game where you stack up the pieces of wood into a tower and then take turns sliding one of the wood pieces out of the stack. The other game is Cup Stackers – that game where you make a pyramid of the cups as fast as you can and then take it down again. The cups and the wood blocks make strong towers if the base of the tower is wide. This keeps the tower stable.

Bill Nye Gravity Demonstration Video:

What You Need:

• Several Plastic or Paper Drinking Cups or Blocks

Build a tower by stacking the blocks or cups one on top of the other. If you are using cups, alternate them so that every other cup is upside down. The towers built from single objects stacked on top of each other don’t get very tall before they tip over do they? Now stack the cups or blocks in a pyramid. Depending on how many cups or blocks you have, the pyramid tower can get pretty tall without tipping over. This is because the weight of the cups or blocks is distributed across a wide base. It’s kind of like the difference between balancing on one foot or balancing on two feet. The wider the base, the more weight that can be supported before gravity will pull an object or stacked objects down.

Here are some websites and books that will help you explore gravity:

• Physics for Kids: Gravity
• StarChild: What Is Gravity?
• Jenga Tropolis Online Game
• ZOOM: Weightlessness
• Tryscience: Gravity in Action
• PBSKids Fetch: Skydiver
• PBSKids Fetch: Stack ‘Em Up
• PBSKids Fetch: Throw Your Weight Around
• The Guardian: Perfect Balance Nails
• Bill Nye Falling for Science
• Bill Nye Weightless Clothespin

Words to Know:

Gravity – The force that pulls everything toward the center of Earth; the force of gravitation on Earth.

Weight – A measure of the force of gravity upon an object

 

 

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What You Need:

• Liter of Diet Soda
• Roll of Mentos Candy

Definitely go outside. Set the liter of soda on a firm surface – a sidewalk will work fine. Quickly – and I mean quickly – add the roll of mentos candy. Stand back!!

Soda is fizzy because it has carbon dioxide pumped into it at the soda bottle plant. The carbon dioxide bubbles just sit there in the soda until you open the top. When you open the top some of the bubble escape making that “whisssssh” sound.

Each mentos candy has a bunch of pits on the surface. The pits are so small you can barely see them. Under a microscope the a mento would look like a golf ball. Those little pits on the surface of the mento are a perfect place for a bubble to form, this is called a nucleation site.

When you drop the candies in the soda they sink and also start making bubbles in all of those pits. The bubbles form and explode making the soda bubble up and out the top of the soda bottle.

Here are some websites and books that will give you more chemical reaction experiments to try:

• Science Buddies: Coke and Mentos – Nucleation Goes Nuclear!
• Steve Spangler Science: Mentos and Diet Coke Geyser
• Science Buzz: Diet Coke and Mentos
• Google Preview Naked Eggs and Flying Potatoes: Mentos Geyser Experiment (pages 144-154)
• Google Preview Science Experiments That Explode and Implode: It’s a Gusher! (pages 18-19)
• Mythbusters Science Fair Book: Are Mentos and Diet Cola the only way to Make a Geyser? (pages 10-12)

Words to Know:

Nucleation Site - A place where a gas can form bubbles.

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What You Need:

• 2 Balloons
• Water
• Candle/Matches

Have an adult help you light a candle that can sit safely on a table. Blow up one balloon and tie it closed. Hold the balloon a couple inches from the candle flame. What happens? It pops, of course.

Now take the second balloon. Fill it with water. Don’t fill it with so much water it starts to expand. This is not going to be a water balloon. Now take the balloon with water in it and blow it up the rest of the way. Tie it closed. Hold this balloon a couple inches above the candle flame. Does it pop? How long does it take?

Balloons are made out of rubber. Rubber heats up really fast so the first balloon pops fast. Water molecules take a long time to heat up. The heat from the candle is soaked up by the water inside the second balloon so that balloon does not pop right away.

Science Experiment Idea: Try different temperatures of water in the balloon. If the water is warmer it seems like the balloon would pop faster. Test it out and see. Try ice water, room temperature water and hot tap water (NOT too hot to touch!). Make sure you use three balloons that are exactly the same. Measure the same amount of water into each balloon. Hold each balloon the same distance away from the candle flame. Remember that you only want ONE variable in an experiment. The variable is the one thing that changes, in this case the variable is the temperature of the water. Use a stopwatch to time how long it takes for the balloon to pop.

Here are some websites and books to help you understand and experiment with the fireproof balloon:

• Rubber Bands and Heat
• Solve the Mystery of the Unpoppable Balloon
• The Fireproof Balloon
• Purdue: The Fireproof Balloon Demonstration
• Science at Home: Fireproof Balloon
• Science Made Simple: Fireproof Balloon
• Google Preview: Super Simple Things to Do With Balloons: Way Cool Water Balloon (pages 18-19)
• Google Preview: Science Experiments That Explode and Implode: The Unpoppable Balloon (pages 10-11)

Words to Know:
Heat - To increase in temperature.

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Many of you have probably played with a kaleidoscope. It is a tube that you hold up to your eye. You point the tube toward light and then slowly turn it. As you turn the tube you can see patterns of colors at the other end of the tube. A kaleidoscope works by reflecting light.

Light travels in a straight line. When light bumps into something it changes direction. If light bumps into something shiny it reflects back in the direction it came from. Think of light like a bouning ball. In a kaleidoscope there are shiny surfaces. If you make your own kaleidoscope you can use mirrors or aluminum foil. When you point the kaleidscope toward light, the light enters the kaleidoscope and reflects back and forth between the shiny surfaces inside the kaleidoscope. Since you have filled the end of the kaleidoscope with little shiny objects, the light bounces off those too and makes the interesting patterns of color. As you turn the kaleidoscope the little shiny objects move which makes the patterns of color move.

Here is a video that will show you how to make your own kaleidoscope:

Here are some websites and books that will help you understand how kaleidoscopes work or build your own:

• Build Your Own Virtual Kaleidoscope
• National Geographic Kids: Bedazzled Kaleidoscope
• NASA: Making a Kaledioscope
• TLC Family: Make a Kaleidoscope
• Toilet Paper Roll Kaleidoscope
• PBS Kids: Fetch Kaleidomania
• Kaleidoscope History
• How Products Are Made: Kaleidoscope

Stomp Rockets, Catapults & Kaleidoscopes
Build Your Own Mini Golf Course (Kaleidoscope page 18)

Words to Know:

Reflect: To bounce off.

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Crystalsare 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:

• Glass Jar
• Pencil or Pen
• String
• Pipe Cleaner
• Borax
• Pitcher
• Measuring Cup
• Tablespoon
• Hot Tap Water
• Piece of Yarn or Cotton String, about 6 inches long

You can make crystals using Borax – a detergent booster located in the soap section of the grocery store. We made a snowflake shape out of pipecleaners to see if we could make a snowflake crystal. Fill a pitcher with 3 cups hot tap water. (Not so hot that you can’t touch it!) Add 3 tablespoons of Borax for each cup of water (9 tablespoons!). Stir the mixture.

If all of the Borax dissolves, add a little more Borax and stir. Add Borax until the water can’t dissolve it anymore -  the mixture is saturated. That means the water is holding as much of the Borax as it can. In fact, this solution is supersaturated, that means the water is holding even more Borax than it normally would because the water has been heated. Now pour this supersaturated solution in the glass jar.

Make a shape out of the pipe cleaners and tie one end of the string to it. Tie the other end of the string to one end to a pen. Hang the pipe cleaner shape down in the jar with the pen across the top of the jar to keep it from touching the bottom of the jar. Watch what happens in the jar over the next few weeks.

 

Here is what our crystals look like after growing on the pipecleaner snowflake for about 2 weeks. The secret to good crystals is having a supersaturated solution.

Science Project Idea: Grow three different borax crystal snowflakes. You need three glass jars that are exactly alike. Fill one with cold tap water and one with hot tap water. Get an adult to help you fill the last jar with boiling water. Now add Borax to each jar until the Borax will not dissolve anymore. The warmer the water, the more Borax will dissolve in the water. That’s because heating the water helps it become supersaturated. Now add the pipecleaner snowflakes and compare the crystals that grow over the next couple of weeks. Which jar has the most crystals? Which jar has the largest crystals?

This video shows you how to make rock candy – a cool crystal you an eat. To make rock candy you need to make a supersaturated solution. That means you have to heat up the water on the stove, so get a grown-up to help you with this one.

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

• San Diego Natural History Museum: Grow Your Own Crystals
• Exploratorium: The Science of Rock Candy
• Exploratorium: The Science of Cooking
• Science Bob: Make Your Own Rock Candy
• Family Fun Crystal Tree
• Scholatic: Homemade Rock Crystal Candy
• Martha Stewart Crafts: Borax Snowflakes
• Baking Soda Stalactites

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

Here are some books that gave good directions for growing different kinds of crystals:

• Science Rocks! Crystal Creation Pipecleaner crystal snowflakes (pages 16-17)
• Prize Winning Science Fair Projects for Curious Kids – Crystal Creation (pages 81-82)
• Mixtures and Solutions – Solubility Try This! Growing Crystals (page 22-23)

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.
Supersaturated – When a liquid is holding as much of a solid as it can…but then can dissolve a little more because it is heated.

 

 

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