We were very busy in 5th Class this week finding out how water expands when it is heated and contracts when it cools. We showed this by making our own thermometers.We filled  a bottle with cool water and a couple of drops of food dye. We moulded playdough around the top of the bottle so no air could escape. We stuck in a straw, filled a basin with boiling water and put the bottle into the basin.As the water in the bottle got hot, we saw it rise up through the straw and bubble out over the top! As time went on during the day, the water cooled down and as we predicted, it went back down the straw! It’s great being young scientists in Ratheniska!