I gave out some sheets with pictures of clouds (which I took from Wild Weather), some card, cotton wool and foil. The children made their own cloud identification charts.
We talked about pressure. I put a balloon over the top of an empty bottle and lowered it into a cup of boiling water. The balloon expanded as the air inside the bottle got hotter.
We then made barometers (following the instructions from Easy Science for Kids). Each child stretched a balloon over the top of a glass jar. Then we taped a long straw to the middle of the balloon. We made card board guides so that we could see when the stick moved up or down.
I showed the children an anemometer next and talked about how it measured wind speed.
The children made their own simple anemometers by attaching a polystyrene ball to a string, then tying the other end if the string to the top of half a paper plate.
We had a discussion about calibration. The children took it in turns to calibrate their anemometers by holding them in front of a fan alongside the electronic anemometer.