Home > Random Stuff > Fizzing Dancing Corn

 

By Ruth Barnard


 

Concoct a fizzing explosion, watch the corn kernels dance and learn about the science behind this enchanting spectacle.

Grab what you need from the pantry and let's experiment…

 

     

What you need:

• Tall clear jar or cup

• Large Shallow container (optional- for catching overflowing liquid)

• Bicarbonate of Soda (Baking Soda)

• Popcorn kernels

• Vinegar (we chose white to keep the solution clear)

• Water

• Spoon

• One measuring cup

 

What to do:

1. Fill half of the jar with water and sit it in a large shallow container

2. Add about 1/4 cup of vinegar

3. Add 1 tsp of corn kernels into the water and vinegar mixture

4. Add 1–2 tsp of bicarbonate of soda and observe what happens 

 

Boogie Time: Put on some music and see if the corn moves to the rhythm


 
     

 
     


What did you see?

There will have been fizzing and bubbling when you added the baking soda. It may have even flowed over the sides of the glass. Then you would have seen that the popcorn kernels look like they are dancing as they repeatedly glide to the surface and back down, dancing for quite a while.


 
     

Why do the popcorn kernels dance?

The Chemistry of the Dance

1. The chemical reaction between the bicarbonate of soda and vinegar produces carbon dioxide gas – you see this reaction as the liquid bubbles and froths.

2. The carbon dioxide bubbles cling to the surface of the popcorn kernels and when there are enough bubbles clinging to the kernel they carry the kernel to the surface of the water. Remember our last density experiment? Bubbles are less dense than water which means they will float to the surface.

3. When the popcorn kernels reach the surface the carbon dioxide from inside the bubble is released so the bubbles will disappear and the kernels will sink back to the bottom again.

 

The Physics of the Dance

Newton's second law of motion says that the acceleration of an object is determined by the unbalanced (or net) forces acting on it.

In our experiment there are three forces at work;

1. Gravity which pulls down on the kernels

2. The buoyant force of the kernel which pulls it up (but not much)

3. The buoyant force of the carbon dioxide bubbles which pulls the kernel up

That's two ‘up' forces and one ‘down' force. The bubbles give the extra buoyancy needed to lift them to the surface.

 

Let us know how your experiment went…

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