errr… probably when I was about 5. My mum had taken us to some caves and shown us the stalagmites and stalatites. The guide told us that they formed from water seeping in from above and dripping down. So, when I got home that night, my clever idea was to pour a bucket of water on the top bunk-bed and wait until the stalagmites formed. My mum wasn’t very impressed.
The first experiment I ever remember doing sounds pretty boring now, but it made a big impression on me. At school, the teacher told us to fill several beakers of water to exactly the same level. Then we put one in a warm place, one in a very cold place, one at room temperature and the last one at room temperature but with a cover on it. Then for a week or two we marked the water level on each to follow how much had evaporated. I was only about eight years old, and I was amazed to find that having a cover, or being cold meant that much less water evaporated, while at a warm temperature the water evaporated very quickly. I didn’t understand the principles behind it back then, but I thought it was very cool!
My first experiment ever was probably in my undergraduate laboratory studies.. I have no idea what is was though! It might have been something like studying harmonic motion. The first experiment in my PhD was done on a computer simulation – looking at the strain field from a stiff tumour being squashed!
The first experiment I remember doing was at primary school where we put different objects into a tank of water to see which ones floated and which sank.
I don’t really do ‘experiments’ as such in my current work, but one of the first things I did in cancer epidemiology was to test cells from cervical cancer to see whether they had the HPV virus in them.