I am presuming you are referring to the three sciences that we study:
- Biology: This is the study of living things and the environment. The subject covers everything from animals and their organs, family trees, food chains and reproduction, through to plants, trees and the natural environment and how all these co-exist with each other. You can specialize in an area for higher study, for example you can choose to focus on just plants, how they absorb sunlight to live, and many other aspects. This branch of science is very practical and often involves field trips to learn about the outside world first hand.
- Chemistry: This branch of science is very technical and involves a lot of equations. Chemistry is all about the elements and compounds that are found on our planet. You learn where they come from, and how to create new chemicals from the basic elements. There are often experiments involved to see first hand these elements being created or reacting. Subjects often looked at are the various stages of petrol based substances, which start off with dense diesel and get lighter all the way up to fuels such as ethanol gas.
- Physics: Physics is a wide branch of science. It looks at everything from the forces that act on us on a daily basis, to the planets and outer space. Gravity is a subject commonly looked at in this field, and calculating mass through speed and velocity is another popular equation. Again, physics uses a lot of equations to explain things and these can be very confusing at times. It is a very skilled branch of science.