- Maths
- Ready-made model
- Class 1 to 9
Pascal’s Law Physics & Mathematics Working Model for School
Code B0G2T8D85L
- Paid for and delivered by Amazon. The current price and the delivery date for your PIN code are shown there.
- Sold by Gurukul Technicals Institute, Delhi.
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In this project guide
Ready-made model
About this model
A working model that demonstrates Pascal's law, the principle behind hydraulic lifts, brakes and jacks. Students can use it to show how a small force on a small area of an enclosed liquid produces a much larger force on a bigger area, and to work through the simple mathematics of area ratios.
How it works
The science behind it
The idea the model demonstrates, in words you can use in your report and when you explain it.
Pascal's law states that pressure applied to an enclosed liquid is transmitted equally and undiminished to every part of the liquid and to the walls of its container. Pressure is force per unit area, P = F/A, measured in pascals, where 1 Pa = 1 N/m². In a hydraulic system, a small piston of area A1 and a large piston of area A2 are joined by liquid. Since the pressure is the same on both, F1/A1 = F2/A2, so F2 = F1 × A2/A1. If the large piston has ten times the area, it gives ten times the force. Energy is not created, though: the large piston moves only one-tenth as far, so the work done, force times distance, stays the same in the ideal case. Liquids are used because they are nearly incompressible. Hydraulic jacks at car service stations and the arms of backhoe excavators on Indian construction sites use this idea.
Make it yourself
Make a syringe hydraulic lift model yourself
Build your own version from scratch, or use the steps to understand how the ready-made model is put together before you present it.
What you need 10
Step by step 8 steps
Fill the small syringe, the tube and the large syringe with coloured water, pushing water back and forth until no air bubbles are left.
Fix both syringes upright on the base with their nozzles down and the tube running between them.
Measure the inside diameter of each barrel, work out each area with A = πd² ÷ 4, and then the area ratio A2 ÷ A1.
Place five coins on the small platform and add coins to the large platform until neither plunger moves: the large side holds several times as many.
Compare the ratio of coins (large ÷ small) with the area ratio you calculated, and explain any shortfall by friction in the syringes.
Push the small plunger down 3 cm and measure how far the large one rises; check that small distance × small area equals large distance × large area, so no energy is gained.
Fill the bottle with water and squeeze it over the tray: water squirts from every hole with about the same force, showing that pressure is passed on equally in all directions.
Mount everything with a card showing P = F ÷ A and F2 = F1 × A2 ÷ A1, your measured areas, and your results table.
Read this first
Safety first
Go through these points before you build or switch anything on. Younger students should do this with an adult.
- Use only needle-free syringes; if a syringe came with a needle, ask an adult to remove and dispose of it safely.
- Do not force a plunger against a blocked tube; the tube can pop off and spray water.
- Wipe up spills at once so nobody slips, and keep water away from electrical items on nearby tables.
- Let an adult make the holes in the bottle, using a heated pin or a compass point.
Troubleshooting
If something does not work
The usual problems with this model and how to fix them. Open a problem to see the fix.
The large plunger moves in jerks or springs back
There is air in the system, and air squashes while water does not. Refill the syringes under water and push out every bubble.
The coin ratio is much smaller than the area ratio
Friction between the rubber seals and the barrels uses up part of the force, especially in the large syringe. Work the plungers in and out a few times, add a drop of cooking oil to the seals, and mention friction as a source of error.
Water leaks at a nozzle
The tube is loose. Use a tighter tube or bind the joint with a cable tie.
The large plunger does not rise at all
The load is too heavy or the tube is kinked. Take off some coins and straighten the tube.
Exhibition day
How to present it
A running order for the exhibition table or the practical, step by step.
Push the small piston gently and let the judges watch the large piston rise, then state the ratio of their areas.
Work out one example on a chart, such as 10 N on 2 cm² lifting 50 N on 10 cm².
Explain why an air bubble spoils the effect: air is compressible, so part of the push is wasted squeezing it.
Connect the model to real machines like a hydraulic jack, car brakes and a dentist's chair.
Practice
Viva questions
Practice questions on this model, with short answers. Try each one aloud before you open the answer.
State Pascal's law.
Pressure applied to an enclosed fluid is transmitted equally and undiminished in all directions throughout the fluid.
What is the SI unit of pressure?
The pascal (Pa), which equals one newton per square metre.
If the output piston has five times the area of the input piston, what force does it give?
It gives five times the input force, because F2 = F1 × A2/A1 when the pressure is the same.
Does a hydraulic lift break the law of conservation of energy?
No; the larger piston moves through a proportionally smaller distance, so the work done on both sides is equal in the ideal case.
Project file
Project file outline
The headings of the project file, in order. Give each heading its own section and write it in your own words.
Free ebook: Writing a Science Project FileContents
- Aim: to verify Pascal's law and show how a hydraulic lift multiplies force
- Introduction: pressure, P = F ÷ A, and its unit, the pascal
- Statement of Pascal's law
- Construction of the syringe lift and the pressure bottle
- Calculation of the plunger areas and the area ratio
- Observations: loads balanced on each side, and distances moved by each plunger
- Why force is multiplied but work is not
- Uses: hydraulic jacks, car brakes, excavators and dentists' chairs
- Sources of error and conclusion
Buying checklist
Before you buy
What to check before you order the model, and what to do when it arrives.
1Before you order
- Check that pressure and Pascal's law are in your syllabus, and whether your teacher wants calculations with the model.
- Look at the listing photos to see how many syringes the model uses and of what sizes, so you can prepare your area calculations.
- Carry a small bottle of water and a cloth on the day in case it needs topping up.
- Keep the box for safe transport.
- Check the delivery date for your PIN code on the marketplace, and order well before the exhibition or practical.
- Practise explaining it. Judges ask what the model shows and why; knowing the science matters as much as the model. The viva questions above are a good place to start.
2When it arrives
- Test it on arrival and look for air bubbles or leaks, which you can fix well before the exhibition.
Next steps
Take it further
Ways to turn this model into a bigger investigation or a stronger exhibition entry.
Use three syringes of different sizes and show the force multiplication for each pair.
Fill the same lift with air instead of water and show why hydraulic machines use liquids.
Design a hydraulic arm with three syringe pairs for lifting, turning and gripping, and explain each joint.
Audience
Who it suits
Suits Class 8 to 11 physics and mathematics exhibitions on pressure, fluids and simple machines.
- ClassClass 1 to 9
- SubjectMaths
- TypeReady-made model
Free to read
Free ebooks for this topic
Free PDF ebooks from Gurukul Technicals Institute on the science, the making and the presenting of projects like this one.
- Free PDF ebook
Maths Working Models and Activities
Make maths visible: models for number, geometry, algebra and data
- Free PDF ebook
Physics Working Models Explained
Twenty classic models, how each works and how to make it
- Free PDF ebook
Your Science Exhibition Guide
Choose a project, build it, present it and answer the judges with confidence
- Free PDF ebook
Writing a Science Project File
How to write the report, from the cover page to the bibliography
