What is water pressure?

  • Water pressure enables water to flow along pipes.

  • Water pressure is created by the weight of water trying to flow to a lower height.

  • Water pressure can be used for cleaning.

A plumber discusses water pressure and its practical applications

What causes water pressure?

Water will naturally flow downhill. A reservoir holds a lot of water and is usually quite high up. The weight of water in the reservoir provides the pressure to force water through pipes lower down.

Water pressure is bigger if there is a greater height of water feeding the pipes below. You can demonstrate this by making three holes in a plastic bottle, one above the other, and then filling the bottle with water. The water will flow fastest out of the lowest hole because there is more weight of water above it.

Water pressure can be also created by pumps where water is needed to be pushed to places that are higher up.

This short demonstration will show that water pressure increases with depth

Why does water flow through pipes?

Water pressure pushes water through any available hole. If you puncture a balloon several times and fill it with water you will see it coming out of all the holes in every direction.

Pipes are like holes for water to flow through. The pressure pushes water along the pipes even when they bend. We can use pipes to direct the water to a specific place. The pressure needs to be sufficient to make water flow quickly through the pipes but not too much because it can make the pipes come apart.

Why is knowledge of water pressure useful?

Understanding water pressure is important for plumbers who need to make sure that water can flow properly through all of the pipes.

High water pressure is used by dentists to clean teeth and it is also used by people at home using pressure washers to clean cars and driveways.

Water pressure quiz

Test your knowledge of water pressure with this quick quiz.

Where next?

Discover more about this topic from around Bitesize.

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