Solids, liquids and gases are called the three states of matter. Liquids can flow or be poured easily. They are not easy to hold. Liquids change their shape depending on the container they are in.

One of the most important tasks for physics is to describe natural observations using a minimal set of principles. This approach allows researchers to understand phenomena of impressive complexity ...

At the end of a lecture on astronomy, describing how the planets orbit the Sun, a little old lady at the back of the room stood up and said: "What you've told us is all rubbish. The world is really a ...