﻿ Activities
 2.11 Activities
"Lab-in the kitchen" exercise: What is density?
1. Lab 1

You need a metal spade, a bucket and crushed ice.
1. Fill the bucket with ice.
2. Put the metal spade on top of the ice. Leave the bucket at a cold place (freezer/fridge) for the night.
3. Check up 15-20 hours later. What has happened to the spade?
4. Explain what has happened.
1. Lab 2

You need a big glass jar, a bottle and ink.
1. Fill the jar with warm water
2. Fill cold water in the bottle and stain it with ink
3. Put the bottle into the jar and observe
4. Explain what has happened.
1. Lab 3

You need a big glass jar, a bottle and ink.
1. Fill the jar with cold water
2. Fill warm water in the bottle and stain it with ink
3. Put the bottle into the jar and observe
4. Explain what has happened.
1. Points to ponder
Can you make any conclusions on what happens when a warm sea current hits an area with cold water?
What about cold water mixing with warm water?

What is heavier (having higher density) - warm or cold water?

This boat floats nicely on salt water.
Will it lay lower or higher in freshwater? Why?

What has higher density - freshwater or saltwater? How do you know?

Look up Archimedes Law on the internet and try to apply this on the boat question.

What is heavier - salty or freshwater?
Have a look at the map over Ocean currents.
What happens when very salty water flows with the gulf stream towards the North Pole?

What will happen if the water in the Polar sea is brackish or almost freshwater?
Find out the meaning of the words "halocline" and "thermohaline circulation"