1 Activity: Submarine Corn and Currants

Supplies per student:

Clear plastic cup

Seltzer water or clear carbonated beverage

10 dried currants

10 corn kernels

1 tsp salt in small container

Question: What do you think will happen when we add corn kernels and currants to the fizzy water?

Directions: Distribute cups of seltzer water. Add corn kernels and currents and observe what’s happening. Ask them what they observe. The corn kernels and kernels should initially sink then float and sink. Ask them why they think this is happening. After discussion, let them add the salt to the water. There should be a lot of bubbles that will quickly disappear. The corn kernels and currants should sink.

Theory: The bubbles gather at “nucleation points;” tiny indentations on the kernels and corn which causes them to float. When they reach the surface the bubbles float and the kernels and corn sink. The cycle repeats again. Salt also has nucleation points which rapidly pulls the carbon dioxide out the the seltzer.

Grades: Appropriate for 1st – 4th grades

Time: 15 minutes

Clean up: Liquids can go down the drain. Gather, as best you can, the kernels and currants and toss them in the trash. I gather up the cups in a trash bag and wash them for reuse after class.

Notes and Hints: Students may work in group of 2. I usually use both currants and corn together, but one or the other works fine. Remind students to keep their hands off the table, fingers out of the water, and use their eyes only for observations. Students may add the kernels and currents themselves, or you can do it for them. Let them add the salt (in small containers) themselves. If it makes sense, they can take the cups to the sink for emptying. Alternatively, provide a few large tubs on the table for them to dump their cups into.

Image Credit: https://www.youtube.com/watch?v=ctWsPa0DCoA