The School Teachers' Review Body has suggested that, as pupil numbers fall, primary teachers with a science background could take a new, part-time diploma designed to give them the skills to teach chemistry and physics.
The diploma, due to be tested from September, was designed for secondary school teachers without degrees in either subject.
The Government has agreed to give a financial incentive to those who take the course, although it has not confirmed whether it will be the pound;5,000 recommended by the review body.
Up to one in five secondary science teacher training places are unfilled and research on science teachers has found a disproportionate number have degrees in biology rather than chemistry or physics.
Debbie West, 49, teaches science to Years 7 and 8 at the Trafalgar school in Downton, Wiltshire. She switched to secondary teaching four years ago after 23 years in primary schools.
Miss West said: "I have seen it as a great reawakening because, if anything, I had got into a rut. I'd taught key stage 2 for all that time and nothing, even the literacy and numeracy hours, surprised me anymore. I had done it all 5,000 times.
"When I teach science here, I'm as amazed as the students are. I did an experiment with them where you mix two colourless liquids and get a blue precipitate. I said 'Wow!' the same as they did."
Jenny Lawrie, the headteacher of Trafalgar, said Miss West's background made her well suited to teach many subjects. As well as science, she has also taught geography, art and French.
Miss West said she would not go back to primary teaching, but admitted that secondary pupils' behaviour had been a "culture shock".
"There are children here who I've taught in primary school and, even with them, I was surprised how much their behaviour had changed," she said.
Derek Bell, the chief executive of the Association of Science Education, said the new diploma might be attractive to some primary teachers, but warned it could end up weakening primary science.