Bevel the ends of the two tubes and gently insert them into the straws.
Clip the cylinder with the diagram onto the cup.
To simulate the heat of the centre of the earth, boil water and pour it into the cup almost to the top. Place the jar on top of the cup.
Adjust the height of the cylinder to match the aquifers.
Fill the bottle with cold water and slowly press it to feed the aquifer until water comes out from the other side.
Gently rest the bottle while keeping the pressure and opening the cap slightly so that air enters and limits the flow of water.
Screw the cap back and then discard the water in the small glass. Wait 5 to 10 minutes.
eintroduce water into the aquifer. The water will come out warmer on the other side. You can check it with a finger or by comparing the colour of the thermochromic strips on the cold water bottle and the small glass.