Newly qualified science teachers find themselves thrown in at the deep end, often teaching subjects which they have not specialised in to all ages up to GCSE-level, a study has found.
The report described the expectations placed upon NQTs as "completely unrealistic".
The pressures of taking on classes in other science subjects, along with poor support during their induction period, leave many young science teachers dissatisfied with the job within a few years of qualifying.
Roger Lock, from Birmingham university, said: "The bottom line is that somewhere between a quarter and a third still get trial by fire and get slung in at the deep end. As a consequence of their experience they give up."
The study of 59 newly qualified and recently qualified teachers in 13 education authorities found that the guidelines on providing support in their first few years' teaching were not being followed.
Teachers said that while they needed most help with subject knowledge and specific teaching methods, the advice they received usually centered around controlling pupil behaviour and dealing with admin. When they asked for subject advice, some of the NQTs were told to refer to their own old A-level notes, while others were told to enrol on a course.
Allan Soares, co-author of the study, to be published later this year, said: "Young graduates come in thinking that they are going to teach their subject specialism, but in reality they are expected to teach right across the board to key stage 3 and 4 ... some department heads expect that of NQTs but not of established staff."
Most teachers work for 90 per cent of the academic timetable, but 80 per cent said they were asked to provide cover in other classrooms as a result.
Nearly half (44 per cent) said this happened on a weekly basis. Half of the newly qualified science teachers and 37 per cent of the recently qualified said they were left dealing with unfinished coursework from their predecessor.
Helen Coles, 24, moved to Arden language college, Solihull, West Midlands, in September after a difficult induction year as a physics teacher in her old school. She had to take low-ability classes with behavioural problems, was given ICT to teach because she was "young" and had little contact with her mentors. "I totally understand how daunting it can be for new science teachers," she said. "Most of my support in my induction year came from fellow NQTs."