Τhe present project concerns a case study carried out on students attending the second class of High school who follow the Positive Sciences' direction, during teaching the Laws of Gases under two different teaching approaches. The first teaching approach made use of software simulating the alteration of gases and was held for two consecutive years on 43 students. The second teaching approach concerned laboratory teaching and was also held for two consecutive years on 41 students. In this project the procedure of each teaching approach is presented as well as the conclusions drawn after comparing the two approaches. The comparison led to a third teaching approach being suggested which will combine the first two.