...that make you realise why you became a teacher.
We were doing science - a topic of keeping warm - and I had set up an investigation to see how effective hands are at working out how warm water is;
There was a bowl of iced water for the left hand, a bowl of hot water for the right hand, and a bowl of tepid water in the middle of both.
Each child came out, put their hands into the cold/hot bowls and then plunged both into the tepid bowl. The looks on their faces was a picture - confusion / disbelief and complete shock at feeling the water being both hot and cold at the same time!
And once they had all tried out the investigation, they were superb at discussing what was happening. In the end, they did work it out, and decided that a thermometer would be much better to measure the warmth of the water.
Let's hope that tomorrow they are just as enthused.

