Studies have shown that misconceptions about photosynthesis often have its origin from the early years of school. The purpose of this thesis is to examine if it is possible to, in a short period of time, teach pupils about photosynthesis. This has been done by carrying out a lecture for 9 year old pupils. Qualitative interviews were done to evaluate the pupil’s knowledge in the subject, one before the lecture and the other one after one week. The result shows that simple and pedagogic lecture methods could help the pupils reinvent there wrong image about how the tree uses photosynthesis, to a more complete picture without using complex words like carbon dioxide and chlorophylls.