A simple and fast experimental method of determining absolute zero temperature is presented. Air gas thermometer coupled with pressure sensor and data acquisition system COACH is applied in a wide range of temperature. By constructing a pressure vs temperature plot for air under constant volume it is possible to obtain--by extrapolation to zero pressure--a reasonable value of absolute zero temperature. The proposed way of conducting experiment allows students to "discover" intuitively the existence of minimal possible temperature and thus to understand the reason for introducing the concept of absolute zero temperature and absolute temperature Kelvin scale. It is a convincing and straightforward method to enhance understanding the general concept of temperature and support teaching thermodynamics and heat--mainly at secondary schools. This experiment was used with our university students who are being prepared to teach physics in secondary schools. They prepared physics lesson based on this material and then discussed didactic value of this material both for pupils and for teachers.