When a substance is heated it’s molecules move faster. You can see this in a pot of water when you heat it on the stove. As the water gets hotter its molecules begin to move until the water is boiling.
When gases are heated, the same thing happens. As gas is heated up the amount of space the gas takes up increases. You can see this by heating up a bar of soap.
You have to use a bar of soap that floats. To make sure you have a bar of soap that will work, float it in a bowl of water. A bar of soap will float because it has air bubble whipped into it. Ivory soap will work for this experiment.
What You Need:
Bar of Soap that Floats
Bowl of Water
Break or cut the bar of soap into four pieces. Put the pieces on a paper plate and microwave for 1 minute. Watch the ivory soap through the microwave window.
As you heat the soap molecules in the air bubbles move quickly away from each other, or expand. This is called Charles’s Law. The same thing happens when you pop popcorn or cook a marshmallow .
Sciece Experiment Idea: Choose different kinds of soap to see what will happen when they are heated up for one minute in the microwave. Be sure to heat each bar of soap up on the same kind of plate and make sure you heat each bar for the same amount of time. The variable in this experiment is the soap, everything else has to be the same. Do the bars of soap each react the same way when they are heated up in the microwave? Why do you think so? Tip: Choose ivory soap for one of your trials – it’s cool!
Here are some books that will help you learn about and experiment with heated gases:
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. Charles’s Law – as temperatures of a gas increase, so does its volume. Simply, heated gases expand. Heat – to make hot or warm.
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:
Your Favorite Drink (Soda, orange juice, lemonade, etc.)
Quart-size zip-lock bag
Gallon-size zip-lock bag
2 cups ice
1/4 cup salt
Fill the quart size bag with your favorite drink and zip it closed. HINT: Make sure the bag is zipped really good or your slushie will taste bad when some of the salt leaks into your bag. Put the quart size bag inside the gallon bag. Add the ice and salt to the gallon bag. Zip the gallon size bag closed. Now shake the bag a lot – even play catch with it…gently. In about 15 minutes you will feel the ingredients in the quart size bag starting to firm up. What started out as a liquid is changing to a solid. When it feels done take the quart size bag out of the gallon size bag. Rinse it off good in clean water. Then open the bag, squeeze the slushie into a glass and enjoy!
TIP: It’s OK for a dog to lick the ice, it won’t be in your drink anyway. Tip for the dog…lick the ice BEFORE the salt goes in!
And if you’re feeling like something with a few more ingredients, try this, ziploc bag ice cream!:
Your favorite drink is a liquid until it gets really cold. Your liquid drink would be pretty good with ice just floating in it…the ice cubes would make the drink colder…but the ice cubes would not make the drink freeze into a slushie.
Ice forms when the temperature of water is 32 degrees or colder. You don’t want the ice cubes to melt IN your drink, you want your DRINK to turn slushie. In order to make your drink turn slushie you have to get it really cold. Salt lowers the melting pointof water. To make a slushie you want the temperature around the bag of your favorite drink to be lower than 32 degrees so your drink will freeze. When you add salt to the ice cubes you lower the melting point of the ice cubes by several degrees. The ice cubes stay colder, longer – long enough to turn your drink slushie. Your salt/ice mixture will make your slushie faster than your freezer! That secret is the catalyst – the salt.
Science Experiment Idea: Make 3 different quart size bags each filled with the exact same amount of your favorite drink. Fill each of three gallon size bag with the exact same number of ice cubes. Add 1/8 cup of salt to the first gallon size bag and label it with a sharpie, “1/8″. Add 1/4 cup of salt to the second gallon size bag and label it “1/4″. Add 1/3 cup of salt to the third gallon size bag and label it “1/3″. Have a couple friends help you shake and smoosh the bags to make the slushies. Time how long it takes each of the bags to turn into a slushie. Which amount of salt makes a slushie the fastest?
Here are some websites and books that will help you understand the thermodynamics of slushies…and ice cream too!
Words to Know: Heat - To increase in temperature. Melting Point – The temperature at which a substance will change from a solid to a liquid. Thermodynamics – The study of the transfer of heat. Catalyst – Something that makes a change happen faster.
When you cut open an apple it doesn’t look good for very long does it? After even just a few minutes an apple can start to look brown inside. The apple turns brown because you cut the apple open and exposed what’s inside the apple skin to the air, which has oxygen in it. Oxidation is a chemical reaction that takes place when a substance combines with oxygen. When apple flesh combines with oxygen it turns brown. The browning of the apple is called oxidation.
Another kind of oxidation you probably have seen is rust. When metal comes in contact with oxygen a chemical reaction takes place – oxidation. In this case the result of oxidation is rust.
What You Need:
3 Apple Slices
1 Orange Slice
1/2 Cup Orange Juice
3 Small Plates
Carmel Dip and the Rest of the Apple Slices (optional)
Put one apple slice on each plate. One apple slice leave alone. Pour the orange juice over one apple slice, pour orange juice over one apple slice and lay the orange slice on top of the last apple slice. Wait a couple hours. How do the apple slices compare? Which one is the most brown?
Here are some websites and books to help you understand oxidation:
If you love airplanes, try out some of these paper creations. If you understand how the forces of aerodynamics work, you can make a plane that flies far. In The Kids’ Guide to Paper Airplanes the directions are really clear with color photographs to help you make the folds correctly. The planes start out easy and get harder and harder as you move through the book. The last plane requires 18 folds! The author even includes some tips for getting these planes to fly far.
What You Need:
Do you know why paper airplanes fly? They fly because of the forces that affect movement on earth. These forces are thrust, drag, lift and gravity.
Here are some websites that will help you understand aerodynamics and how to make good paper airplanes:
Science Rocks! Fly a Dart (page 52) and Fly a Glider (page 53)
Words to Know:
Lift- The force that is opposite the weight of an airplane and holds the airplane in the air. Drag – Air pushing back on the plane as it moves forward. Thrust – What makes the airplane move forward. This can be a propeller, a jet engine, or your throwing arm. Gravity – The force that pulls objects back to the earth. Aerodynamics – Aero means air and dynamics means motion. Aerodynamics is the study of motion through the air.