# Investigating Human Power – Physics IAA

Yes, another boring science IAA test. This time it’s physics investigating human power by walking up stairs. I bet the guy who made that experiment up was Steven Hawkins. Anyway, I will tell you mostly everything you will need to know for the test here.

So, as I have already said, this experiment is an investigation into human power. In this experiment the:
Independent variable – Work done (measured in Joules)
Dependant variable – Time (measured in seconds)
Remember, the dependant variable you can’t change and is always on the ‘x’ axis.

Here’s a list of equations you may need for your test:

Work Done = weight X height raised
Power = work done / time taken
Total height = step height X no. steps
Weight = mass X gravity and remember gravity on earth is 10N/kg

Method – these are things that made the method reliable

1. Collect the following equipment: a half-metre ruler and 7 stop clocks, a book for recording the data and a pencil or pen.
2. Measure the mass of the climber using a set of scales to 1 decimal place.
3. Measure the height of several steps to 1 decimal place.
4. Average the step height for your measurements.
5. Place 7 people at appropriate places on the flight of stairs. Each should have a stop clock.
6. Start a countdown for the climber  to start AND to start all the stop clocks.
7. Each timekeeper should stop their clock immediately when the climber reaches their step. Record the times from each timekeeper in a table.
8. Repeat the experiment three times and take an average.
9. Ignore any anomalous data and repeat to compensate.

The experiment was made valid by: (point / explanation)

• Keeping the ascendant the same as different people have different walking paces and weights.
• Keeping the time keepers the same as different people will have different reaction times.
• Used the same stairs so ascendant climbed the same height of stairs.
• Same steps the time keepers were places on so that the times will be similar to each other.
• Same type of countdown to stop and prevent any confusion.

The experiment was made reliable by:

• Using seven time keepers, not just one.
• Measure mass of climber to 1 decimal place.
• Average the step height.
• Place time keepers evenly out on the stairs.
• Use a countdown.
• Repeat experiment.
• Average the times.
• Ignore anomalous results and repeat to compensate.
Your graph should look something like this:

Showing that the time it took to walk up the stairs had a constant effect to work done. (line is a line of best fit)