Passed/Failed: An education in the life of Kathy Sykes, broadcaster and science professor at the University of Bristol

'I'd make ice cream with liquid nitrogen'

Kathy Sykes, 42, is Professor of Sciences and Society at Bristol University. Her most recent BBC2 series was 'Alternative Therapies'. She is on the judging panel for NESTA Famelab 2009, the competition for budding scientists; the winner will be announced at the Times Cheltenham Science Festival which starts on 3 June 3 (http://cheltenhamfestivals.com /science/).

I remember making a tower out of Lego when I was six. I had cogs going round it and I was trying to make one cog turn the next one and so on: a perpetual motion machine. It didn't work and I couldn't understand why.

My father was a physicist but it was my mother, an English teacher, who taught me about atoms, which I thought was a fabulous concept; I liked the idea of everything being made of similar, basic units.

I didn't spend all that much time messing with electronic devices or playing with chemistry sets. I spent more time outdoors climbing trees. I thought science was incredibly hard and impenetrable and not for the likes of me.

My parents went out to the States and I went to Immaculata School in Durham, North Carolina, until I was seven. We sang and danced a lot with enthusiasm and I still do both now. I don't remember anything academic.

At Dunmore Juniors in Abingdon, just south of Oxford, they noticed that my brother and I had an alien accent and I was teased about that. I lost my American accent in a couple of hours. I remember myself as being a shy kid but every year my reports talked about me as being lively and witty. I was very conscientious and worked hard.

In the final year we had a great maths teacher, Mr Dennis, who said: "If you were hanging out of a window and someone behind tried to shoot you, what would happen to the bullet?" He was introducing us to relativity without making a big fuss.

Fitzharrys, also in Abingdon, was a fairly ordinary comprehensive with a mixture of great and appalling teachers. I didn't like science much and was going to drop physics until a new teacher, Mr Quill, persuaded me to do it at O-level. I got a healthy string of As – and even a B in French, which was a miracle as one of the French teachers managed to suck out your will to live. I went out later with VSO to teach in Zimbabwe and asked myself "What makes you think you can teach?". I decided that even if I tried, I couldn't be as bad as she was.

I didn't always tell people my exam results and I stopped playing tennis and swimming for the school. You could get your head beaten in for doing well at everything.

I did maths, physics and chemistry at A-level and got three As and a couple of S-levels. I went to Bristol University and had a great time: I learnt to scuba dive and went caving; I played squash a bit. There were 110 of us doing physics and a lot of people had been to public schools and seemed articulate and clever but I said to myself: "Look, Kath, you nutcase, just because the guys sound really clever doesn't mean they're brilliant at physics!"

In the third year we did a project, which was much more like real science. I did mine with another girl (on biodegradable plastic) and we got the Project Prize. I was viva-ed for a First but I got a 2:1. If it had occurred to me that I could get a First, I probably would have worked a little bit harder.

I took four years over my PhD. I was also giving talks to school kids and Women's Institutes. I would give a lecture about the physics of ice cream and would include the laws of thermodynamics as well as making ice cream with liquid nitrogen.