Chemistry sounds like a really complicated topic, and if you were to look up the definition it may be scary. But in simple terms chemistry is simply the subject that tries to understand how the world works and functions at the very smallest scale. For example, you could observe a drop of water just by looking at it. If you divided that drop of water in half you could still observe it by simply looking at it. But what if you divided it in half again, and again, and again… say about 20 times? The tiny drop of water you’d have left would be so small you could no longer see it with just your naked eye. You would need a magnifying glass, or a microscope just to show that it even exists. Imagine you kept dividing this water droplet in half over and over again. You’d have to ask yourself the question – can I cut up this water droplet so many times that it is no longer a water droplet? The answer is yes.
At some point you will cut up that water droplet enough times that all that will be left is a single molecule of water. This single molecule of water is still water, but if you were to divide it even one more time, you would no longer have water! This is because a single molecule of water consists of only three atoms. One atom of oxygen and two atoms of hydrogen. These hydrogen and oxygen atoms alone are not water, they are atoms. Water is simply a specific combination of hydrogen and oxygen. This is the very small “scale” that I described above. This is the very small scale that chemistry is mainly concerned with studying. In the study of chemistry you will start to ask and answer questions such as: what is a hydrogen atom and how is it different from an oxygen atom within water? Why does water have two hydrogen atoms and one oxygen atom instead of two oxygen atoms and one hydrogen atom? What other atoms exist and how do they form other molecules similar to water? …and so on…