Iced With Your Kids!
Exploring the fun science of melting
ice
Have you ever wondered how skaters are able to glide over an ice
surface? Would you be surprised to learn that skaters are actually
skimming over a thin layer of water, as opposed to ice?
Materials:
Procedure:
Step 1: Push the cork into the bottle so that a 2.5 cm (one inch)
of it sticks out of the bottle.
Step 2: Balance the ice cube on top of the cork.
Step 3: Cut a piece of string or wire about 40 cm (about 16
inches) long. Tie a fork to each end.
Step 4: Hang the string over the ice cube.
Step 5: Carefully place the bottle in the refrigerator. The string
will slowly pass through the ice without dividing it in two.
Take a moment to discuss with your kids the science behind what is
happening.
The pressure of the string or wire is enough to melt the ice
immediately below it. Water forms under the string or wire. As the
string slides down through the ice, the water freezes again just
above the string.
This is similar to what happens when you skate. As you push your
blade, the pressure of your body on the thin skate blade actually
forces a track of solid ice to be converted into liquid ice. So,
in effect, you are riding on a track of water. This thin trail of
water provides a frictionless path for the skater to glide along.
This layer of water then freezes again after the skater has passed
over it.
Ice forms when the temperature of water reaches 0 degrees Celsius
(32 degrees Fahrenheit). When you add salt, that temperature
drops. For example, a 10-percent salt solution freezes at –6 C (20
F), and a 20-percent solution freezes at –16 C (2 F). On a
roadway, this means that if you sprinkle salt on the ice, you can
melt it. The salt dissolves into the water in the ice and lowers
its freezing point.
Mad Science aims to spark the imagination and curiosity of
children by providing them with fun, entertaining and educational
activities that instill a clear understanding of what science is
really about and how it affects the world around them . For more
information call (727) 895-5595 or (813) 655-6643 or visit our
website at
www.MadScience.org/wsTampaBay
back to top
|
