There are several studies of students' conceptions of energy both before the energy concept had been introduced in science instruction and after this had been done. The results show that conceptions both before and after energy teaching mainly reflect the use of energy in students' life-world domain; this is especially so where an energy concept is in use that differs from the science energy concept. There are also a few studies available on teachers' (Veiga, Costa Pereira and Maskill, 1989. Kruger, 1990) or teacher students' (Baird, Fensham, Gunstone and white, 1987) conceptions of energy, which indicate that teachers and preservice teachers are often not in full command of the science energy concept and hold ideas that are similar to the ideas of their students.