Connections

Cold Bodies

Deep freezing is a great way to preserve something. Archaeologists have found incredible specimens of ancient animals and humans frozen into the ice -- the cold has maintained the integrity of the bodies for millennia. There are also many stories of people who fall into ice water for up to 30 minutes. The cold temperature slows down their bodies so much that instead of drowning, they can survive until rescued. (Don't try this at home!) It's easy to see why one might think you could harness the power of the cold to keep a body in suspended animation -- say, for a long trip to a far away planet, as is seen in sci-fi movies. Or maybe even freeze a dead body to keep it pristine in the hopes of one day bringing it back to life. There are certainly scientists who are trying to figure out how to do this, but the road ahead is unclear. The fact is that freezing human cells can dehydrate and destroy them beyond repair [[link to animals activity]] -- and no matter how well a body is preserved, no one has ever succeeded in bringing someone back to life from the dead.

Find some books, movies, Internet stories, or TV shows in which there are examples of humans being put into cryogenic suspension. Examine the stories closely – do they describe the futuristic mechanism for how the suspension works? Does the science make sense? What parts seem factual and what parts seem like science fiction?

Hands-on Activity

How To Make Strawberry Liquid Nitrogen Ice Cream

NOTE: Please read the following safety tips at the following Web site before beginning any activity using liquid nitrogen: http://webs.wichita.edu/facsme/nitro/safe.htm

Ingredients:

• 5 or more liters of liquid nitrogen and associated safety gear
• 2 quarts (1.9 liters) of Half and Half
• 1 cup (237 ml) of sugar
• 4 teaspoons (20 ml) of vanilla (optional)
• 2 cups (473 ml) of mashed strawberries (or other fruits or some chocolate syrup or any flavoring you'd like!)
• Wooden spoon
• Wire wisk
• Large plastic punch bowl

Directions:

1. Mix the Half and Half, sugar and vanilla in a large plastic punch bowl with a wire wisk.
2. Add the flavoring. Wire wisk the mixture further if needed.
3. Pour a small amount (about 250 ml) of liquid nitrogen directly into the plastic punch bowl.
4. Stir the mixture with a wooden spoon. Be careful not to splash! (Helpers should be wearing gloves and goggles!!)
5. Keep adding small amounts of liquid nitrogen until the mixture becomes too thick to stir.
6. Allow any excess liquid nitrogen to boil off before serving.

Five liters of liquid nitrogen should be enough for two batches of ice cream.