As the temperatures heat up, its time to pull out the ice and do some "cool" science.
1. Ice Spikes
Have you ever seen bumps or spikes come up from the ice cubes in your ice cube tray? SnowCrystals.com has a great discussion of ice spikes, how they form and how to grow some of your own. For more pictures and a movie, try Spikes on Ice Cubes.
2. Ice cube rescues
Give your child(ren) a challenge to "rescue" ice cubes floating in a glass of water with only a piece of string and some salt. Then watch this video to see how it is done.
3. Freezing and thawing water
Freeze water in various-sized containers and then set the ice "sculptures" out to thaw. (Set them in in deep bowl indoors or outside on a sidewalk or patio where a little melt water won't matter.) Time how long it takes various sizes and shapes to melt with a watch or clock. Does size or shape influence melting time? How?
Try freezing a water-filled water balloon (set in a bowl first). Once it is frozen, what happens when you toss it? What happens when you freeze a balloon filled with air in a bowl of water?
4. Floating and sinking
Create an ice cube boat and float it to emphasize that ice is less dense than water.
- ice cube tray
- cold water
- pie plate or shallow bowl
- plastic wrap
- triangle of paper
- clay (optional)
Fill the ice cube tray with water. Cover the tray with a tight layer of plastic wrap, which will hold up the toothpicks. Stick a toothpick in the center of each cube, enough so that there is a least one for each child. When the ice cubes are frozen, remove from the tray. Insert a small triangle of colored paper on each toothpick to make a sail, and float the ice cubes in a bowl of cold water (the colder the better). Do the boats float? Do they stay upright? If not, try adding some clay to the bottom until the ice cubes are balanced. (This may be difficult at first, if the oily clay doesn't stick to the wet ice. I found it did work with patience.)
5. Moving on to dry ice
Dry ice (frozen carbon dioxide) is available at many grocery stores. Just remember that it is much colder than regular ice and will require special handling. Always use gloves, and tongs are a good idea too. Never put dry ice in a swimming pool!
See this Steve Spangler video for some ideas and handling suggestions.
Ice is so much fun to experiment with in the summer. Let me know if you have any other experiments to do with ice or activity tips.
For more information, try these books:
and these related subjects:
Ice Scientist: Careers in the Frozen Antarctic (Wild Science Careers) by Sara L. Latta
Pioneering Frozen Worlds by Sandra Markle