Make a Quarter Sing and Shake Using Dry Ice
In this science experiment, kids make metal objects sing and shake while exploring sublimation and the phase changes of dry ice. Watch how we did this on TV!
Dry ice is frozen carbon dioxide. As it warms, it goes from being a solid to a gas without ever becoming a liquid. This is called sublimation. When a room-temperature quarter or spoon is placed on the ice, it accelerates the sublimation process, and as the gas forms, it makes the object move and vibrate, causing an eerie sound like screaming!
Dry ice is dangerous and should only be handled by an adult. If touched, it can cause severe burns. If enclosed in an air-tight container, it can also cause the container to pop open unexpectedly. Always keep children out of reach of the dry ice, always use tongs or thick leather gloves when moving the dry ice, always store it in a container with ventilation, and never attempt to chop or break it in a way that bits could fly up into someone’s face or eyes.
Dry ice is widely available in grocery stores (even more so around Halloween) and is not very expensive. Store in a container with ventilation until you are ready to use it. Be aware that dry ice "melts" (sublimates into a gas form) fairly quickly unless you are able to keep it extremely cold -- so buy a bit more than you think you need. What may seem like a huge block the day before may dwindle to a tiny chunk (or nothing) by the next day.
When you are ready to do the experiment, AN ADULT should carefully place a small block of dry ice on a surface that can withstand extremely cold temperatures (metal or wood are good choices). Observe the gas that is coming off of it. You are watching sublimation. Unlike an ice cube, which would melt into a liquid, dry ice "melts" into a gas! Note also that the gas appears to float downward instead of upward -- that is because carbon dioxide gas is heavier than air.
AN ADULT should place a quarter on top of the dry ice so that it is standing on its skinny edge (not laying on its flat round surface). The edge of the quarter will quickly melt a groove into the ice, allowing it to stand there without you holding it. The quarter will begin to vibrate quickly back and forth, causing a sound much like screaming!
Now kids can try placing a metal spoon or soda can on the dry ice. It will also vibrate and make a weird sound!
In both cases, warm metals cause the dry ice to sublimate, and the gas released makes the objects vibrate.