• Baking soda
• Vinegar
• Water
• Un-popped popcorn kernels
• Measuring cup
• Shallow pan
• Tall glass or jar
• Teaspoon

1. Place the glass in the centre of the shallow pan and add several popcorn kernels.
2. Ask students to predict what will happen when each of the following steps occur:
3. a) 1 cup of water is poured into the glass
4. b) 1/4 cup of vinegar is poured into the glass containing the water
5. c) 1 tsp. of baking soda is added to the vinegar solution in the glass without stirring
6. Record the students’ answers on a data sheet under 'predictions'.
7. Pour 1 cup of water into the glass and have students record their observations.
8. Pour 1/4 cup of vinegar into the water in the glass and have students record their observations.
9. Add 1 tsp. of baking soda to the vinegar solution (do not mix!) and have students record their observations.

• Try this experiment with objects such as rice, dried kidney beans or paper clips.
• Investigate what happens when the experiment is repeated with the different objects.
• Replace the baking soda with salt or sugar and see if you get the same effect.

• Why the popcorn kernels are 'dancing'?
  

When the vinegar and baking soda are mixed together, a chemical reaction occurs between the acetic acid in vinegar and sodium bicarbonate in baking soda. This causes a release of chemical energy and the formation of a gas (carbon dioxide).

The gas bubbles that form adhere to the outside of the popcorn kernels and raises them to the surface of the liquid. This is because the kernels and bubbles together have a lower density than water and thus rise to the surface of the liquid. At the surface the gas bubbles burst, releasing the carbon dioxide into the air. Once the bubbles have burst, the density of the kernel is once again greater than that of water and the kernel falls towards the bottom of the glass.