What is science?

According the books and the notes "Science is defined as the study of things visible and non-visible things around us.".. But in my own words science is the reason for what happens around us.
Science teaches us about the possiblities of the particular thing to happen. An apple falls from a tree, science gives the reason why it falls. Rocket flies into the space, science says its because of action and its equal reaction. We breath we eat we walk we talk every reason is given by science.
Generally science is divided into 3 topics.

• Physics
• Chemistry
• Biology
  

Physics deals with the measurements and physical causes.
Chemistry deals with the reactions of the chemical compounds to give a specific product.
Biology deals with the study of life and living beings.