Joanne Downing, one of this year's four winners of the Salters Prize for the Teaching of Chemistry, reflects on her research experience working on anti-cancer drugs: "I haven't changed the world - but I enjoyed trying."
This year, none of the winners has taught for more than seven years and each has a passion for the subject. Sandra Clinton says:"I'm fascinated by why things bond, react, are coloured, and how you can see that so precisely."
For Ezi Papakostopoulos, it was the "abstractness of chemistry" that first drew her. Ezme Turla says: "I like logic and clarity and the way of thinking matches mine, yet it's so practical."
Ezi Papakostopoulos has been teaching for six years. She works at St Paul's girls' school, an independent selective secondary in London with 670 pupils, including 200 in the sixth-form.
She bubbles with enthusiasm when she talks about chemistry - how everyday concepts such as "soft", "hard", and "coloured" involve such fundamental principles as electron bonds.
"I did science A-levels because I was good at them," she says. "But on my thin sandwich course at Brunel it became clear to me on my second placement, working on the effects of fertiliser effluent and algal bloom, how important chemistry is in the world."
While researching her Ph.D in industry and the environment, she took on some tutoring, which she says was "fun". "Teaching was getting to me more and more, and as the research money ran out I was doing more and more of it," she says. By the time she had gained her Ph.D, she had a job at St Paul's; the PGCE came later, in service.
"I was nervous when the Salters judges came because I do teach in a demanding way," she says. "I always go in a bit above what the exam demands. We're lucky that the girls are all bright and motivated - they have to be able to concentrate. In this case, we were doing electron structure for the first year of A-level.
"Pupils who have done chemistry GCSE often say, 'They lied to us' when they get to A-level and find that the structure is more complex. I like to take it a bit further to convince them that this time it's 'truly' true.
"I always say it's the difference between looking at something with a magnifying glass and a microscope."
Teaching tip: "Communicate enthusiasm, be interested in what you're talking about - pupils always know if you are not."
Sandra Clinton has been teaching for seven years. After her degree in chemistry and management studies from Sussex and a PGCE, she spent five years in a tough 11-16 school for boys in Crawley, Surrey. She says this taught her "a lot about people".
She moved to Brighton, Hove amp; Sussex sixth-form college in East Sussex two years ago to gain experience in teaching academic chemistry. The college has 1,300 students, 80 of whom are doing AS chemistry, with 60 taking A2. More than 90 per cent pass the exam.
Ms Clinton breaks up lessons into an opening demonstration, time for students' experiments to be recorded and compared, and an IT-graphing session that allows them to discuss the theory behind the practice. One student, Ben, says: "It's nice to be able to understand what's going on with everyday substances."
Her students say she is "firm but fair", as she reminds them that they are meant to be looking at analytic techniques with pipette and beaker, searching for "a hint of pink", rather than discussing last night's TV. "Ladies," she announces, swirling a delicately pink beaker full of ethanoic acid in solution, "this is the colour."
Teaching tip: "Know your experiments inside out. Science will always throw up wrong results and anomalies: you need to be able to explain and cope."
Esme Turla has been teaching for four years. After her chemistry degree from Southampton and supply teaching, she got a job at Gumley House School, an 11-18 girls' RC comprehensive in Richmond, Surrey with 1,100 pupils. Thirty are studying chemistry in the sixth-form.
"I had to teach myself chemistry after I switched from A-level humanities," Ms Turla says, "so I worked out how to break things down into basic parts and then build it back up again."
Working with different abilities across different age groups is part of that same challenge, she says, and one which would keep her in the classroom rather than aiming for promotion.
When the Salters judges visited Gumley House, they were struck by the purposeful atmosphere. An Ofsted report noted how well developed the questioning is at the school, and how mature the pupils are in taking responsibility for their own learning.
"It's modern," Esme says. "It's find out for yourself."
Teaching tip: "Try everything. If one thing doesn't hit home, vary activities. If you sometimes feel you're hitting a brick wall, ask your technical team for help. Analyse what you are doing all the time. Don't be afraid to see when you've gone wrong - that's how you can improve.
"You need a tough skin to be able to say: 'Yes, I did that wrong. I can learn from it.'" Joanne Downing has been at Loughborough High School in Leicestershire for six years. "We teach separate sciences here, so I can teach chemistry - which I love and know about," she says.
Loughborough is an independent grammar school for 589 girls, aged 11-18. "They are well motivated, but they may not find chemistry easy," she says. "You can push the limits and try things out that less motivated pupils might find difficult."
With GCSE classes of 15-20 and 40 pupils divided into three groups taking A-level, the staff-pupil ratio is enviable. Double science at GCSE and chemistry at A-level regularly show 100 per cent pass rates, with more than half the pupils scoring above B grade. Nearly half of the sixth-form now take chemistry.
Ms Downing uses arresting analogies. For instance, she explains bonding in solutions by asking: "If you have 10 boys and 50 girls in a disco, how likely is it for one girl to find a partner? But if you have 50 boys and 50 girls, how likely is it then?"
Salters judges saw a lesson on rates of reaction with Year 11. Students were quickly engaged by the iodine clock experiment in which the sudden change in colour from translucent to blueblack occurs at different times, depending on different concentrations of iodine.
"It's got that Wow! factor," she says. "They can't help themselves being impressed."
Once the visual interest was established, a CD-Rom helped to explore the microscopic world of particles colliding and the likely effect of increasing the concentration. Finally, the students were challenged to adjust their own concentrations until they could get the switch to happen in exactly one minute. One group did it to the second, disappointing others who had been pleased with 54 and 56 seconds.
Such moments, when students stream out chattering and excited, make her feel lucky, Joanne Downing says. "The reward comes from the students themselves, when the strugglers achieve understanding or the reluctant ones find a spark of enthusiasm."
Teaching tip: "Create an atmosphere in which the students feel confident, are not afraid to ask questions and are not afraid of being wrong. And always begin with a practical."