# Investigating Levers AQA Triple Science P3 – Stretch Project!

Introduction

This is a great “technical practical” that you can use to investigate how a lever works, but in
a fun practical way. It requires some tricky kit, so you might need to go do to the local tyre shop to see if they will let you have a go!

Equipment…

• Force Sensor (range 0.1N to 500N)  (link – for suggested type of sensor)
• Alloy rim with tyre
• Metal Lever (0.6m)  (link – suggested type)
• 30cm ruler
• Black marker pen
• Multimeter – set to ohms

Safety: to avoid cuts or crushing injury wear gloves and heavy duty shoes, in case your hands slip on the lever as you apply forces.

Method

1. Calibrate a resistance based force sensor using weights and a multi-meter set to ohms. Create a graph so you can convert resistance to a specific force.
2. Put car wheel on the floor on its side.
3. Glue a force sensor to the tyre lever on the top of the “load side”
4. Put markings for distance on a tyre lever every 0.05m from the pivot point and pivot point itself.
5. Hold the lever with one hand at the nearest point to the pivot, apply enough force to pull the rubber over the rim.
6. Record the distance, reading on the multimeter in a table then use the graph to convert to a load force which should also be recorded.
7. Replace the rubber and repeat steps 5 and 6 but 0.05m further away. Record all the results in a table.
8. Graph the load force v distance from pivot and look for a pattern.
9. Repeat with a 2nd wheel and compare graphs.

Control Variables

1. During the experiment you must control certain factors. You hand must not slip or move from the distance to the pivot
2. Force sensor must not change angle against the rim or tyre or the results will vary for the resistance
3. Pivot point must stay fixed
4. Temperature may have an effect on the force sensor so all results must be collected on the same day and in the same place.