Can a small push lift a heavy load?

Change the output piston size. Test how a hydraulic lift trades distance for force.

Starting notebook…

Simulation · Mechanical Systems

How does output piston diameter affect lifting force when input force and input piston size stay fixed?

A hydraulic system uses an enclosed liquid to carry a pressure change. In this ideal model, pressure is equal at the two pistons. A larger output piston has more area for that pressure to act on, so it can provide a greater force. Diameter is the distance across a circle; area is the surface inside it. Doubling diameter makes area four times as large. A gain in force comes with less output travel, not extra energy.

Review the related lesson →

Science words you will use

A hypothesis is a possible explanation. A prediction is what you expect to observe. The independent variable is what you change or compare; the dependent variable is what you measure. Controlled variables stay the same in a fair test. Qualitative observations describe what you notice; quantitative observations use numbers and units.

Accuracy means closeness to a trusted value. Precision describes how closely repeated readings agree. Repeating a result does not prove it is accurate. A pattern between two quantities does not, by itself, show that one caused the other.

What good work includes

Change one variable and record the fixed setup with units.
Distinguish diameter ratio from area ratio, and force capacity from load weight.
Use evidence to explain the force–distance trade-off and model limits.

Plan your investigation

My scientific notebook

Plan your investigation

Use your own words. You can return and change your ideas as you collect evidence.

My research questionWhat can you investigate using this equipment or record?My hypothesisGive a possible explanation: I think… because…My predictionIf… then I predict… because…What I change or compareName the independent variable. In an observation study, name what you compare.What I measureName the dependent variable and its units.What stays the sameChange only output diameter. Keep input diameter, input force and load fixed. Check the slider readouts after resetting or choosing a preset.My procedure and changesUse repeatable steps. Record changes to the plan and why you made them.Reading my equipmentWhat is the smallest marked division? What units and rounding will you use?

Your apparatus

Build your hydraulic comparison

Open MechSimulator in a second tab. Choose SI units. Use the sliders for Input Force, d₁ (input diameter) and d₂ (output diameter). Record Capacity F₂ in newtons, not Load W. The load is the weight to be lifted; capacity is the model’s ideal available force. Use the readouts to confirm that each slider change has taken effect.

Open hydraulic simulator →

The original simulator opens in another tab. Keep your notebook here. Use sliders and confirm the readouts before recording.

Materials & safety

MechSimulator Pascal’s Law simulator
Calculator and digital notebook

This is a computer model. Do not test real vehicle jacks, hydraulic presses or heavy suspended loads. A real hydraulic activity needs a separate teacher-approved setup.

Suggested procedure — adapt and record changes

Predict what will happen if output diameter doubles. Explain whether diameter ratio and area ratio are the same.
Open the simulator and choose SI. Set input force to 100 N and input diameter to 20 mm using the sliders. Keep load at 120 kg. Confirm all readouts; use arrow keys on a focused slider for small changes.
Change only output diameter. Start at 30 mm and record Capacity F₂. Add a row with output diameter in mm and capacity in N. In observations, record input diameter, input force, load and pressure.
Test at least four output diameters, including 40 mm and 80 mm if available. Confirm each displayed diameter before recording. Keep every other setting fixed.
Calculate (output diameter ÷ input diameter)². Multiply by input force and compare the prediction with Capacity F₂. Use full calculator values until your final answer.
Compare capacity with Load W to predict lift or no lift, then press Run Simulation. Explain why a force capacity value is not proof the load will rise. Return to one setup and check the reading; this repeat is not independent real-world evidence.
For an extension, open Work & Energy. Record the input and output travel shown, with units. Check whether the larger piston travels less far. Explain why the ideal model does not prove a real machine is 100% efficient.

Collect · check · compare

Your data and graph

Use the displayed output diameter and Capacity F₂. Keep input force, input diameter and load fixed. Record actual readouts, not invented trial values. Start a new group if you deliberately change the input setup.

Graph titleGraph view

The table keeps your exact readings. On a small screen, scroll inside the table or graph to see the rest. With a keyboard, focus it and use the arrow keys.

Add readings to enable data and graph downloads.

Explain your results and reflect

Think like a scientist

Explain, question and reflect

Patterns in my resultsUse at least four diameter settings. Is the graph straight? Compare 40 mm with 80 mm: what happens to area and force capacity? Use numbers from your table.Limits and possible errorsDiscuss rounding, reading the correct readout and limits of the ideal model. Real systems can lose energy through friction and leakage. Replaying a model does not measure real-machine uncertainty.My conclusionAnswer your research question. Your result does not have to match your prediction.The evidenceUse measurements, units and trial numbers to support your conclusion.Why the evidence supports my conclusionConnect pressure, area and force. Explain why equal pressure does not mean equal forces. Describe the distance trade-off without claiming the machine creates energy.What I would improve or test nextWhat would you change? Why? Revisit your hypothesis and prediction.

A new question to explore

Compare two setups with the same output/input diameter ratio but different diameters. Keep input force fixed. Predict whether capacity stays the same and whether pressure does. Test your prediction and explain the difference.

Keep your work

Your lab report

Preview your notes, measurements, calculations and graph. Choose Print / Save as PDF in the report, or download an HTML copy. Submit that PDF in Google Classroom using your teacher’s instructions. This website does not submit your work.

Student name (optional)Class (optional)Investigation date (optional)

Restore notebook backup

A backup is a JSON file for restoring this notebook. It is different from your finished report. Keep your own copy before clearing browser data or changing devices.