Standard: 4-PS3-3 Conservation of Energy and Energy Transfer
Materials:
two ice cubes
two similar looking plates/containers, but made out of different material
one made of metal
one made of an insulator material (rubber, ceramic, etc)
Summary:
Place an ice cube on each plate, making sure each plate is at room temperature. Watch how one ice cube melts rapidly, while the other does not. Get students to wonder why. Encourage students to write down observations, wonders, and their hypothesis in their science notebooks. Eventually explain that one plate is a conductor and one is an insulator, demonstrating how conductors do well at transferring heat, while insulators prevent heat from easily transferring.
Focus Questions:
Why is one ice cube melting much faster than the other?
What is an insulator? What materials are thermal insulators?
What is a conductor? What materials are thermal conductors?
Posted by: Lauren Pio
Standard: 4-PS3-2 Conservation of Energy and Energy Transfer
Materials:
Two identical small, wide-mouthed jars (baby food jars are perfect)
Hot water
Cold water
Food coloring
Index cards or squares of waxed paper
Scissors
A large, shallow baking pan
Summary:
Prep two jars of hot water with the same color of dye, and two with color water with a different color of dye. Cover the opening of a cold water jar with an index card and place it on top of a hot water jar. Take away the index card and watch the colors begin to mix. Repeat again, this time with the cold water jar on top. This second of water will not mix like the first. The molecules in hot water move faster than those in cold water. Hot water molecules bounce around and leave gaps. This makes hot water slightly less dense than cold water. So when you put the cold water on the bottom, the denser cold water stays there. But when you put the cold water on the top, heat molecules rise. So the colors mix right away.
Focus Questions:
Why doesn't the water mix when the hot water is on top?
What is different about the molecules in hot and cold water?
What is density?
How is heat transfered?
Posted by: Lauren Pio
NGSS
2-PS1-4. Construct an argument with evidence that some changes caused by heating or cooling can be reversed and some cannot
5-PS1-2 Measure and graph quantities to provide evidence that regardless of the type of change that occurs when heating, cooling, or mixing substances, the total weight of matter is conserved.
Posted by SciShow Kids on Youtube
Join Jessi as she uses science to make your own ice cream! In this tutorial, SciShow Kids walks you through the steps and the "why" of how you can make your own ice cream.
You'll need...
1/2 cup of milk, half and half, or cream
1/2 teaspoon of vanilla
1 tablespoon of sugar
4 cups of ice
1/2 cup of salt
1 Ziploc sandwich bag
1 gallon-sized Ziploc bag
Gloves, a towel, or something to keep your hands safe
First, combine the dairy of your choice, vanilla, and sugar into the sandwich bag. Make sure it's closed nice and tight and set it to the side.
Next, place your 4 cups of ice into the gallon-sized bag. Add your 1/2 cup of salt to the ice in the gallon-sized bag.
Notice how the ice seems to get even colder? This is because the ice may be cold enough to freeze water molecules, but it is not cold enough to freeze salt-water molecules. The salt lowers the temperature that water needs to be at to freeze and melts the ice. This is why we put salt on our driveways in the winter- to melt the ice! As the ice melts, it draws in heat and makes what's around it much colder; like your ice cream!
Place the sealed sandwich bag inside the gallon bag now. Seal the gallon bag tightly! Grab your towel or gloves and shake the bag for about 5 to 10 minutes. If this sounds like a long time, grab a friend or a parent and take turns shaking the bag!
Focus questions:
Could you completely undo this process? Why or why not?
How did the ice cream change from a liquid to a solid?
Posted by Gracie Bostwick