You will need the following items: ice cube, glass of water, string and salt. Once students have been assigned partners, give each pair a string and a glass of water with an ice cube floating in it. Have students try different methods to pick up the ice cube using only the string. Next, demonstrate a solution by sprinkling salt over the ice cube. By laying the string on top of the ice cube you can lift it right out of the water. Explain that by adding salt the temperature drops, causing the string to freeze to the ice cube.
You will need one film canister for each student. If you have 30 students, fill five groups of six canisters with different items such as salt, rice and stones. Have each student walk around the classroom shaking her canister and listening to try to find the other students with the same substances in their canisters. Once the students have found their groups, have them try to figure out what is inside without taking the lid off, using sound, weight and balance.
You will need a glass of water, white paper and sunlight for this demonstration. Place white paper on a flat surface where there is direct sunlight. Hold the glass of water over the paper. As the sunlight shines through the glass and refracts, a rainbow will appear. By holding the glass at different heights and angles you change the way the colors are reflected. Explain to students how light passes through water, refracts or bends, and causes prisms of color called rainbows.
You will need a 1-liter clear soda bottle, 3/4 cup of water, vegetable oil, fizzing tablets and food coloring for this project. Pour the water into the soda bottle, then add vegetable oil until it is almost full. Allow a few minutes for the water and oil to separate. Add 10 drops of food coloring to the bottle. The coloring will drop below the oil and mix with the water. Drop half of the fizzing tablet into the bottle. This will create a chemical reaction and cause the water and oil to bubble. Explain to students that though oil and water do not mix, adding a reactor will cause them to interact.