1: Lessons in Term 2

I wish to learn the difference between the three different sciences in secondary school, chemistry, biology and physics. I have a rough idea about the meaning of chemistry and biology, but I have no idea what is physics. I also want to know why it is that the three sciences must be studied separately in upper secondary, and not as one. Also, as mentioned in the intro, I really hope to learn more about science and expand my knowledge about the world around me. In other words, I want to learn more about science. I really hope to achieve that goal I have set for myself.