Temperature

Requirements

You will need 1) an aquarium or similar 2) a refrigerator, 3) balloons 4) a jug and 5) a marker.

Procedure

1. Fill two balloons with water, just so that they will fit in the aquarium.
   There should not be any air in the balloons.
   
   
   
   
2. Place the balloons in a refrigerator (5°C) for one hour – or even longer.
   
3. Fill the aquarium with water to approximately one third.
   
   When the water has settled, the water level is marked with the marker on the outside of the aquarium.
   
       
   
4. The cold water balloons are placed carefully in the aquarium.
   
   Make sure that the balloons are completely immerged in water – possibly by holding them down with an object, which should not get into the water, however.
   
   
   
   
5. When the water has settled, mark the water level with a second line.
   
     
   
6. Now empty the aquarium.
   
   
7. Next, pour hot water in the aquarium so that the balloons are heated.
   
   The larger the temperature difference you can get between the cold and the warm balloons – the easier it is to see a change in water level.
   
   
8. When the balloons are warm, they are removed from the aquarium.
   
   
9. Empty the aquarium once again.
   
   
10. Pour water in the aquarium so that the water level is at the first (lower) marker line.
    
    Note that the aquarium should stand in the same place as when the first line was drawn.
    
    
11. Now, put back the balloons in the aquarium.
    
    
12. When the balloons are completely immerged and the water has settled, the water level is read.
    
    It should be slightly above the upper marker line because the hot water in the balloons take up more space than when it was cold.
    
    

To save time you can run the three lab experiments as parallel activities and discuss them as time passes.