Chemistry

Activity #1

The Big Meltdown

Words to discuss:

salt, solution, temperature, freeze, melt, melt more, faster, color, blue, red

Materials:

1 paper cup per child
food coloring (red and blue)
very cold water
salt
ice on the sidewalk or ground

This activity is best on a sunny day after a snow or ice storm.

Plan:

1. Let children work in pairs. (Give each child one paper cup.)
2. Have them prepare a salt water solution in one cup - 2 tablespoons of salt to 1 cup. Then fill with water and stir. Add one drop of red food coloring to designate that this cup contains the salt solution.
3. Now fill the second cup with water. Add one drop of blue food coloring.
4. Have children dress warmly, then go outside with one child carrying the salt (red) solution and the other carrying the plain (blue) water.
5. Now they pour their cups onto the ice. We want to find out which one melts the most ice. Which one do you think will make the biggest hole? They can now return to the room and go back to check on this experiment later during the day.
6. After returning to their designated spot, they will observe that the salt solution has melted the ice. This is because salt water freezes at a lower temperature than ordinary water. In other words, it has to get colder than 32° F (0° C) before salt water will freeze.

Activity #2

Hot Bubble Fliers

Words to discuss:

bubbles, warm, air, temperature, high, quickly, fast, lighter, cold, moves, replaces, float, rising, currents, breath

Materials:

bubble mixture (1/3 cup Dawn dish soap, 1 cup water and 1 teaspoon of sugar)
container for mixture
bubble blowers

Plan:

1. Let children mix bubble mixture indoors.
2. Go outside on a cold winter day and let them blow bubbles.
3. Observe the bubbles as they float upward.
4. Explain that the child's warm breath makes the bubbles very light and that cold air is heavier than warm air.
5. Why do the bubbles fly up so quickly? How high will they fly? Watch and see.