Loading please wait

The smart way to improve grades

Comprehensive & curriculum aligned

Try an activity or get started for free

Learn About the Application of Liquid Pressure in Hydraulics

In this worksheet, students will apply their understanding of liquid pressure to a new context - hydraulics.

'Learn About the Application of Liquid Pressure in Hydraulics' worksheet

Key stage:  KS 3

Year:  Year 9 Science worksheets

Curriculum topic:   Physics: Motion and Forces

Curriculum subtopic:   Pressure in Fluids

Difficulty level:  

Worksheet Overview

Have you ever noticed that at the dentist's surgery, the dentist has a foot pedal they can press to raise or lower the dentist's chair?


dentist's chair


This is a hydraulic system, and it uses concepts of liquid pressure to work! Hydraulic systems are really useful in technology - we use them in roller coaster rides, in planes, and in construction site diggers, as well as many other examples!




Let's learn about this important application of liquid pressure.


Particles in liquids are close together but randomly arranged. They can move and flow. 


particles in a liquid


Liquid particles can collide with each other, and with surfaces. This causes pressure. 


Liquids have a property that is really useful - they are incompressible. What this means is that you cannot 'squash' liquids into smaller volumes, and this is because the particles in a liquid are so close together. 


Liquids are incompressible, so we can use them in hydraulic systems. You can see an example below.


simple hydraulic experiment


Liquids are incompressible. So, if you press down at point A, the liquid presses up at point B. 


What that means is that liquids can pass on pressure from one place to another. If you apply pressure to a liquid at one end, it applies an equal amount of pressure at the other end. 


So in our example, if 300 Pascals of pressure are applied at point A, then 300 Pascals of pressure are passed onto point B, acting upwards. 


The reason that hydraulic systems can be helpful is linked to the equation for pressure. 



In our system, the pressure at A is equal to the pressure at B. But the area at B is much greater than the area at A. What this means is that the force upwards at B is greater than the original force applied at A! 


We sometimes call hydraulic systems force multipliers because of this - they increase the force!


simple hydraulics


Let's imagine that the area at point B is twice as big as the area at point A. 

That would mean that any force you apply at A gets doubled, and is twice as big at point B!


These systems are very useful in situations where we want to increase a force. In the dentist's chair example, a hydraulic system allows a small force at a foot pedal to be increased to a greater force, enough to lift up a chair. 


Here is another example of a hydraulic system in action, lifting a heavy object. 


hydraulic pressure


A force is applied down, on the left side. The area on the left is 1 cm2. The liquid is incompressible, so the pressure is transferred to the other side. The other side has an area of 50 cm2, so a force that is 50 times bigger pushes up. 


Now that we know a little more about hydraulics, let's try some questions!

What is EdPlace?

We're your National Curriculum aligned online education content provider helping each child succeed in English, maths and science from year 1 to GCSE. With an EdPlace account you’ll be able to track and measure progress, helping each child achieve their best. We build confidence and attainment by personalising each child’s learning at a level that suits them.

Get started

Try an activity or get started for free

  • National Tutoring Awards 2023 Shortlisted / Parents
    National Tutoring Awards 2023 Shortlisted
  • Private-Tutoring-WINNER-EducationInvestor-Awards / Parents
    Winner - Private Tutoring
  • Bett Awards Finalist / Parents
  • Winner - Best for Home Learning / Parents
    Winner - Best for Home Learning / Parents