Salt water and Ice

We looked at how cold water sinks today. First we took a jar of water that had been sitting in the room for a while. Then we added a cube of ice. This floated on the top. Next we added some food colouring and the food colouring followed the icey water as it was melting in the jar.

We then tried the same thing again, this time with a jar of salty water. The ice sat on top again but when we added the food colouring, it just stayed on the surface - it wasnt as dense as the salt water so it didnt sink!

Ice formed in the Antarctic (and the Arctic) is fresh water. The salt in the water gets 'spat out' and sinks. The water below the ice is very salty.

Blubber Hands!

We had a go of this wonderful experiment to see how blubber insulates animals - it really does!

Blubber Hands

How do Antarctic animals stay warm in bone-chilling water?

1.    Discuss how quickly our bodies are chilled in cold water. What do we do to stay warm? (move around, wear insulating wetsuits, get out of the water).

2.    Ask students to list ways in which animals are able to stay warm in cold water (blubber, air in feathers, oil on fur, low surface area to volume ratio).

3.    Have the students cover one hand with a plastic bag.

4.    Put a generous amount of solid shortening into another bag. Have the student put the plastic-covered hand into the bag with the shortening. Knead the shortening to make sure the hand is completely surrounded by shortening.

5.    Cover the other hand with two plastic bags (without shortening). This is the "control."

6.    Place both hands simultaneously into a bucket of cold water.

8.    Have a student time how long each hand remains underwater.

9.    Whales, Weddell seals, and penguins all have blubber.