# what do you learn in physics? what is physics about?

do u use yards, inches, and etc. in other words, do u measure things?

• Physics is about everything. It is how things move and why they don’t move. It is how everything works, your microwave oven uses rays with a smaller wavelength than light!

Physics is the study of matter and energy in space and time and how they are related to each other. Physicists assume (take as given) the existence of mass, length, time and electric charge and then define (give the meaning of) all other physical quantities in terms of these basic units. Mass, length, time, and electric charge are never defined but the standard units used to measure them are always defined. In the International System of Units (abbreviated SI from the French Système International), the meter is the basic unit of length, the kilogram is the basic unit of mass, the second is the basic unit of time, the Ampere is the basic unit of electric current.

Physics studies how things move, and the forces that make them move. For example, velocity and acceleration are used by physics to show how things move. Also, physicists study the forces of gravity, electricity, magnetism and the forces that hold stuff together.

Physics studies very large things, and very small things. For example, physics studies stars, planets and galaxies and other big pieces of matter. Physics also studies small pieces of matter, such as atoms and electrons.

Physics also studies sound, light and other waves. Physics studies energy, heat and radioactivity, and even space and time. Physics not only helps people understand how objects move, but how they change form, how they make noise, how hot or cold they will be, and what they are made of at the smallest level.

[Physics uses numbers. Physics is a quantitative science because it is based on numerical measurements. Mathematics is used in physics to make models and predictions of how nature behaves. The predictions are compared to the way the real world works. Physicists are always working to make their models of the world better.

• Physics is above all about ideas: about how our universe works. It is a study of the underlying principles of our universe. But these ideas are quite precise, and let you predict what will happen when matter and energy move or change. So It is not just a question of things going faster or slower, but of exactly how fast. And so you DO make measurements, and you use mathematical equations to see what happened or what will happen.

People with a good understanding of physics, even basic physics, have a good idea of how the world around them works. They will not necessarily know every detail, but they will have a good idea of how a car works, and how a plane flies, and how electricity powers a washing machine. If it is nothing else, it is a great introduction to the practical side of life!