Dry ice and spooky Halloween fun
Dry ice is often used for spooky effects at Halloween parties. It can also be used for science along with the spookiness.
A bubbling cauldron with smoke rising from the top is a classic “special effect” for a Halloween party. This is often done with dry ice. In addition to adding to the setting of a Halloween party, dry ice can be used for some cool science experiments.
Michigan State University Extension reminds you to use dry ice with caution. Dry ice can be dangerous and damage the skin if not handled with heavy gloves. Make sure there is plenty of adult supervision when conducting experiments with dry ice and remember to keep children’s skin away from this potentially dangerous substance. Dry ice is made of carbon dioxide, which is denser than air and can fill low-lying areas with an invisible, unbreathable gas, suffocating animals and people in those areas. Be aware of where you use this substance and look out for these potential dangers as well.
Dry ice is solid carbon dioxide (CO2). It can often be purchased at large grocery stores where ice is sold or at ice suppliers. Call ahead to see if it the location you are interested in purchasing it from has dry ice in stock. It can be transported in a cooler, and should be handled with thick gloves. Keep it stored in a cooler if you are not using it right away, but keep in mind it will turn into a gas. The longer you wait the more dry ice you will lose. It is best to purchase it as close to the time you plan on using it as you can.
Here are some questions and quick experiments by MSU Extension to try:
Start by talking to the children about the states of matter and how changes happen in states of matter. What is a solid? A liquid? A gas? What is it called when something goes from a liquid to a solid? (freezing) Solid to liquid? (melting) Liquid to gas? (evaporating) Gas to liquid? (condensing) What caused substances to go from one state of matter to another? We are used to seeing water change states, but can other substances changes states too? Can metal melt? What about glass? Plastic? Wood? Can pop freeze? What about vinegar? Oil? Honey?
Children understand that by changing temperatures ice melts into water and that water evaporates into water vapor. Dry ice skips a step and goes from a solid directly to a gas. This is called sublimation. The opposite (gas directly to solid) is called deposition. Why does dry ice do this? Where does the dry ice go when it sublimates?
Put some dry ice in water (use gloves) and watch what happens. What is the fog coming out of the top of the bowl? Does normal ice do that? Why or why not? Does it change anything if you put the dry ice in warm water versus cold water? Why or why not?
Use an infrared thermometer (temperature gun) to measure the temperature of dry ice and normal ice. Why is the dry ice colder?
Put some dish soap in a 2-liter bottle; add some water and dry ice. (NOTE: Do not put the lid on the bottle, the bottle could explode.) How long will the soap bubbles keep forming? Is there anything you can do to get bigger bubbles?
Try blowing regular soap bubbles on top of a cauldron of bubbling water and dry ice. Will the bubbles float on the dry ice fog? Why or why not?
Why does the fog from dry ice sink to the ground? Why are clouds high in the sky? What makes dry ice fog different from clouds in the sky?
Have fun and enjoy a spooky Halloween – and remember to incorporate science as much as you can!
Source: MSU Extension