Tuesday, February 28, 2017

Dry ice bubbles

For our Saturday activity, we decided to experiment with dry ice and dish soap. The result were some amazing bubbles. We dropped a block of dry ice inside a container partially filled with warm water. The only way for the pressure gas was through a tube attached to the side of the container. At the end of the flexible tube was a hose head that the kids dipped in dish soap.

Whenever the lid was placed on the container, the carbon dioxide was forced out through the hose forming large bubbles.  The bubbles pop when coming in contact with body oils so the kids wore gloves to catch them. Some gloves were better than others. In the end, we discovered than dishtowels were the best option.

The kids requested we make 'screaming pennies' with the leftover dry ice.  When the heated pennies are inserted in the dry ice they vibrate and make a high pitch sound.   I had to look up the explanation. When the penny is pushed into the block, the warmth of the metal sublimates the dry ice and causes a change in pressure. As the gas pushes past the coin, the pressure causes that shriek. After some time, the coin forms a larger hole in the dry ice, producing larger air currents that push the coin around, causing it to vibrate and appear to be shivering.

With a range of ages 11 years old - 18 months it is sometimes difficult to find activities that appeal to most. Science seems to be something they all enjoy doing. The educational component is an added bonus!