Pressure

Pressure is the amount of force pushing on a certain area. It can happen in air, water, or any other substance. For example, when you press your hand on a table, your hand applies pressure on the surface. The smaller the area you push on, the greater the pressure. That is why the tip of a pin can go through paper easily—it puts the same force on a very small point.

Pressure is all around us, even when we cannot see it. The air around earth has weight, and this creates air pressure. Although we don’t feel it, air pushes on our bodies all the time. When you climb a tall mountain, air pressure becomes lower because there is less air above you. That is also why it’s harder to breathe at high altitudes.

Water can also create pressure. The deeper you go underwater, the more water there is above you, and the greater the water pressure. Submarines and deep-sea animals must be strong to survive in such conditions. Divers are trained to handle changes in water pressure so their bodies stay safe.

Pressure is measured using special tools. A barometer measures air pressure, and a manometer measures the pressure of gases and liquids. The standard unit for pressure in science is the pascal (Pa), named after the scientist Blaise Pascal. In everyday life, pressure is also measured in units like atmospheres or pounds per square inch (psi).

Pressure plays an important role in everyday life and technology. It allows airplanes to fly because air pressure under the wings is higher than above them. It helps car tires stay firm and water to flow through pipes. Even our own bodies depend on blood pressure to move oxygen and nutrients to all parts of us.

Understanding pressure helps explain how the world works—from the air we breathe to the ocean depths. It connects to many parts of science, including physics, weather, and biology.