I went to St Kevin’s Primary in the Falls Road at the height of the Troubles in Belfast. As a child, you accept what goes on around you as normality, so it didn’t seem particularly unusual. In 1969 or so, the Army came to Belfast and there were soldiers on the streets - armoured cars and people in camouflage, carrying rifles and so on.

There were barricades set up at the end of some of the streets and I would have walked over these things to get to school.

My best teacher was Seamus Crummey. I didn’t know his first name at the time; I just knew him as Mr Crummey. I found it out when I was giving a graduation address at Queen’s University and used him as an example of how our experience of teachers can be influential in our lives - one of his nieces or great-nieces was there, and came up to me later and said: “That was my Uncle Seamus.”

When I went into his class, P6 was a big step up from P5. St Kevin’s had a boys’ section and a girls’ section. The girls played on one side and the boys on the other, and we were taught in separate classes. The set of books we had was also used by the girls’ class. We would put notes in the English comprehension books for the girls - things like “hello from whoever”.

I remember this tall man who was quite stern initially. He was a tall, large man and an imposing figure and had what seemed like a very deep voice.

There was not anything remarkable at the outset - just behave yourself and keep your head down. Then, at some point, he said that on Friday afternoons we were going to do science. Nothing had ever been explicitly stated up to that point about a particular subject - we were just learning. But that sounded really different.

On that first Friday, he took out a big blue box; in it were shiny, laminated cards - science exemplars. Colour- coded, each described the apparatus you needed, the method and what we were going to try and do, and how we recorded the results.

I loved Friday afternoons, but there is one experiment that sticks in my memory: you have a candle in a saucer and a jam jar and some matches. We had to find a candle - the church was next door, St John’s, and we got one from there. Having to gather materials made it fun.

You had to melt some wax into the saucer and prop the candle up. Then you filled the saucer with water and turned the jar upside down over the lit candle and water. The candle burned until it exhausted the oxygen inside and then the water in the saucer replaced the oxygen by pulling up into the jam jar. We were asked to measure the distance from the top of the jar to the bottom and calculate how much water was displaced - a fifth of the height of the jar. I have never forgotten that the amount of oxygen in air is 20 per cent.

Every Friday was a complete joy, but that experiment sticks in my mind. It really helped spark my interest. It made me realise that was the kind of thing I enjoyed doing. I ended up doing experimental physics.

Mr Crummey is now dead but he has a son whom I now know - he is a bit like Rory Bremner, imitating Northern Irish politicians and he has a radio show.

When we went into P6 we knew the 11-plus was coming. The 11-plus was great for people who passed it, but a disaster for those who failed. I thought it was a form of child abuse. My youngest brother failed - it was devastating for him. He is very sporty and a really talented young man, but that failure defined him - he just said: “I must not be good at anything academically.”

Gerry McCormac was talking to Elizabeth Buie

Personal profile

Born: August 1958 in Belfast

Education: St Kevin’s Primary, Christian Brothers’ Grammar, Ulster University and Southampton University

Work: Scientist specialising in space physics and carbon dating, including spell on the NASA Dynamics Explorer satellite programme; 2001-10, pro-vice chancellor, Queen’s University, Belfast; 2010, principal, Stirling University.