Regardless of whether my students are from the IP track, IB track, or regular Express track, I will always ask the same question during my first lesson with them.

“What is the difference between Physics, Chemistry and Biology?”

Blank faces, every time.

If you don’t know the difference between Physics, Chemistry and Biology, you are not alone. It’s not usually properly explained, because when you’re in Secondary 1 & 2, it’s not necessary. You have to study all of it, anyway. It’s only in Secondary 3 & 4 when it matters, because you’ll have to choose whether you’d like to do pure sciences or not, and which sciences you’d like to do. The expectation is that when you have to make a choice, you should already have figured out what each of the sciences is about.

And perhaps, you’ll have some vague idea by that time.

I’d like to change that. I’d like you to know what you’re studying, and how it is relevant to the world around you. I’d like you to figure out what you might like to pursue, in relation to what you might like to do in the future. Even if it has nothing to do with your future, you can’t run away from studying science just yet, so why not spend your time on something you’d have more interest in?

So, let’s get down to it, shall we?

What Is Physics?

Physics comes from the Greek word φυσική (pronounced physikḗ), which means ‘knowledge of nature’. It is the study of two things: matter and energy, and everything there is to do with them.

With matter, we study the motion (movement) of matter through space and time.
With energy, we study what happens when energy is applied to an object.

This is, of course, a simplified definition. Physics encompasses so much more, including astronomy, atomic and nuclear physics, the theory of relativity, gravity, etc. Whatever you see happening around you, that has anything to do with matter, and energy, that’s physics. The way you walk, when you flip a switch and the lights come on, when you aim a basketball, when you heat up a bowl of seaweed chicken in a microwave oven, even when you ride a bicycle – all these things happen in the way they do because Physics.

What is Chemistry?

Chemistry is the study of matter and energy (wait – does this sound familiar?), the properties of matter, how matter can combine or separate to form different substances (with different properties), and how matter interacts with the application of energy.

Chemistry can be split further into 5 different branches:

  • Analytical Chemistry, in which you use qualitatively and quantitatively measure and identify the physical and chemical properties of all substances through observation.
  • Physical Chemistry, in which you combine the study of Physics and Chemistry together to study how matter and energy interact with each other. Examples of Physical Chemistry is the study of thermodynamics, and quantum mechanics.
  • Organic Chemistry, in which you specifically only study about compounds that contain the element Carbon. Organic chemistry is also known as the “Chemistry of Life” because all molecules that make up living tissue have Carbon as part of their make up.
  • Inorganic Chemistry, in which you study metals and gases that do not have carbon as part of their make up (in other words, everything else).
  • Biochemistry, in which you combine the study of Biology and Chemistry together, to study the chemical processes that happen within living things.

(Source: LiveScience)

What is Biology?


Biology is the study of living things. As long as life is involved, it comes under biology. Biology involves explaining aspects of living things, change in living things, even death. It investigations the evolution of living things, and how living things interact with their environment. This is because no living thing exists in isolation from their environment.

The study of Biology includes: animal behaviour, biochemistry, biotechnology, environmental ecology, genetics, marine biology, and even food and drink safety.


So, there you have it. The three branches of science.

You might have noticed, by this point, that there are so many overlaps between the sciences, and that’s just how life works. Nothing is so cleanly divided. After all, through each of the branches, we study another aspect of life, and what happens around us.

Some things are obvious – we take one look, and we can see it. If I push a ball, it moves. The harder I push it, the further it moves. If the ball is too heavy, I might not be able to move it at all.

Some things can be theorized, but we have not yet discovered a way to prove it – there’s still so much to learn about quantum physics.

Some things we never thought possible are being proven possible in very tangible way. For example, supercooled helium, and how it defies gravity.

I hope this helps you to better understand what you are, have been, or will be studying in your Science class from Secondary 1 to Secondary 2, and I hope it helps you to make a more informed choice.

If you have any further questions about this topic, or if you’d like to discuss what choice you’d like to make, based on your interests, feel free to contact me or connect with me via Facebook.


One thought on “Physics vs Chemistry vs Biology

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