Dancing Dime Experiment by I. Reid

The dancing dime experiment is fun for children to do, and shows that different temperatures of air take up different amount of space.  Readers may recognize the author iReid, the talent behind the popular Bunnicula post. Let’s get right to the guest post with a word of caution that a dictionary may be required to follow along. Be sure to see the 27 second demonstration video at the end of the post.
the dancing dime experiment

What most magicians do not want to admit is that besides fast reflexes and the innate ability of humans to be easily distracted, many of their so-called magic tricks rely on simple physics. As the great Eoin Colfer once wrote, “science is taking the magic out of everything.”

The experiment of the Dancing Dime or Burping Bottle relies on simple physics to mystify and hopefully fascinate. This experiment works because of the principle of endothermic reactions. A basic concept in science is that everything wants to return to a whole and neutral state. In endothermic reactions, the whole and neutral states are achieved by absorbing heat (aka energy) from the surrounding area.

The dime dancing is the consequence of a situation akin to the constant breeze at a large lake.

Lakes are probably the easiest for a person to understand. A large body of water often acts as a heat sink as it warms and cools much slower than land or air. A breeze is generated as the body of water tries to push the warmer or cooler air on to shore to achieve equilibrium with the surrounding ambient temperature.

While many enjoy the lake breeze myself included, I must agree with Eoin Colfer. Once one understands physics it’s a bit harder to simply sit back and enjoy the mysteries of mother nature.


Dancing Dime Directions

1. Freeze bottle in freezer area for several hours.

2.  Remove and cover the opening with a dime.

3.  Place drops of warm water over the dime.  The water acts as a little seal.

4.  As the air inside the bottle warms to room temperature, it will take up more space.

5.  As the warm air expands, the pressure will cause the dime to dance or burp.  This will continue for several minutes.

*Note:  Some people put their hands around the bottle to improve the speed of this experiment, but it works to just wait a few minutes. 

*Editor’s note: I. Reid must have swallowed an encyclopedia at some point. 

In simple terms, the frozen glass bottle, dime, and hot water on it all try to achieve the ambient temperature of the room (i.e. the whole and neutral state). This causes a physical reaction of the dime dancing as the cooler air from the frozen bottle clashes with the warmer air from the water. Metal works well in this experiment because it heats and cools quickly.

This is the video of the experiment. Also, find a free printable with the steps in the experiment at this link.

Now for the dry ice experiment!

Dry ice experiment?  Yes, this is the season where you may receive food packages in the mail packed with dry ice, like we did.  Our Thanksgiving cheesecake was packed in dry ice (and good thing we realized that quickly after opening the bag).  So, I immediately went to the Steve Spangler dry ice experiment page to see what experiment we might do, and found this one.  This is the one using warm water and a very few drops of soap.  The experiment is safe as long as the ice is not touched, and there are safety rules on the page.  Use tongs, use gloves (as demonstrated in the video) and be careful.  See more information at this link.

This is a up-close view of our jar. No one was hurt in this experiment!


It was exciting to watch!



You might also like other guest posts by i-Reid at this link.


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