On 29th August, 2018, Ma Man Kei and Lo Pak Sam College invited Prof. Tang Zikang from the Institute of Applied Physics and Materials Engineering at the University of Macau to a give a lunch seminar entitled “Physics behind Heat?”. Prof. Tang began his talk by briefly explaining the history of heat in the 15th to 18th century. He explained physicists was able to precisely deduce the energy value of one calorie in 1850 already. He then moved on to talk about what is absolute zero temperature and the lowest man-made temperature in the laboratory. Prof. Tang concluded the talk by explaining what scientists can learn from the law of entropy and why heat can only transfer from high temperature objects to low temperature objects.