Wednesday, December 29, 2010

Winter science activities

Up here in WI we get plenty of cold weather.  If you have your share try some of these winter fun activities with your family.

1. The Mpemba Effect was discovered in 1969 by a student.  See if you can name the results of this experiment.  

2 plastic containers of the same size
1 C. hot water
1 C. cold water
A freezer or a very cold day

Pour hot water into one container and cold water into another.  Make sure you don't mix up the containers.  Place containers in the freezer or outside to freeze.  Check on them often to see which on freezes first.  According to your results:  what do you think the Mpemba Effect is?

Answer: The Mpemba Effect is a phenomenon where hot water freezes faster than cold.

What happens when water freezes?

1.  1 coffee can with a lid
2.  1 bottle cap
3.  3 pencils
4.  2 heavy rubberbands
5.  duct tape

Fill the can with full with water and put the lid on.  Tape the 2 pencils on each side of the bottom of the can.  Place the bottle cap in the center on top of the lid.  Take the 3rd pencil and place it on the bottle cap.  Take one rubber band and place it around all 3 pencils on one side of the can forming a triangle with the rubber band.  Do the same with the rubber band on the other side of the can.  Make sure the top pencil can't move and place your can in the freezer or outside overnight.  Note what happened.  Did the water expand or contract when it freezes.

Freezing Fizzie

1 bottle lemon lime soda
1 large bowl of ice large enough to bury the soda bottle
several T. of salt
thermometer (optional)

Cover the ice in the bowl about halfway with water.  Sprinkle salt over the ice.  Bury the soda bottle in the ice.  Allow it to stay buried for 30 minutes.  It should not freeze.  After the 30 minutes remove the bottle from the ice and open the bottle.  What happened?  It should have become slushy.  Why did it get slushy?

Answer: The carbon dioxide dissolved into the soda and reduced the freezing point.  And when you opened the soda you released some of the carbon dioxide.  Thus, the freezing point rose again.  The liquid inside was already below that freezing point.  

Have fun and enjoy the cold weather!