Purpose: The purpose of this experiment was to find out how inclined planes work by doing experiments. Five different slopes were used with an object and a scale to measure the work done. It had to be compared with the work done when lifting the object straight up with pulling the object along an inclined plane.
Hypothesis and explanation: If an object is to be pulled 0.2 m up, then it more work is done to pull it over a ramp instead of pulling it straight up because there is a greater distance over the ramp and W = fd. The object has less work done when pulling straight up rather then over a ramp because there is a small distance when going up even though there is a big load force required. I found from previous experiences that more force is required when pulling an object straight up rather than over a ramp. But because of the effort distance is greater than the load distance there would probably be more work done to pull over the ramp and from my previous experiences I know that less force is required to pull an object over a ramp rather then straight up. So when using inclined planes, less force is required but more work is done.
The slopes of the ramp, what angle the ramp was on, were the independent variable. It is found by multiplying the rise and the run of the ramp. I think it is the independent variable because that was what the work depended on. It could be a stand-alone piece of information that did not depend on anything else. Because this is the independent variable, it is shown on the x-axis in a graph.
The dependent variable was the amount of work done. It is the dependent variable because it cannot be found out without knowing the slope. The work is found by multiplying the effort distance and the amount of force used, and the effort distance cannot be found without the slope. So if there is no slope to measure with, the amount of work done cannot be found out. The dependent variable is shown on the y-axis in a graph.
The controlled variables are:
- Mass of object – the mass of the object has to remain the same for all five trials to get accurate data. If the mass changed, it could have given very different data for each trial.
- Height of ramp – the height of the ramp had to stay 0.2 m so that the data collected can be accurate.
- Ramp – the ramp has to be the same ramp for all five trials. For example, a smooth wooden ramp is used for trial one and a rough and carpet-covered ramp is used for trial 2. This would give inaccurate data.
- Same object – the object also has to be the same. Another object with the same mass cannot be used because the surface of the other object might be different. For example, for trial one, a water bottle is used, and for trial two, a toy car with the same mass is used and is pulled along its wheels.
All the controlled variables have to remain the same and must be readied carefully so the data collected is not inaccurate.
To do the experiment we needed:
- Ramp – a wooden ramp to use.
- Water bottle – a half filled water bottle to use as the object to pull up.
- Newton scale – to measure the force of the object.
- Meter stick – to measure the rise, run, height, effort distance, and load distance.
- Books – to prop the ramp.
- Laptop – to record data and make calculations.
- Marker – to mark distances on the ramp.
- Camera – to take photos throughout the experiments.
After all the materials were collected, we went through the experiment step by step:
- Hook scale to water bottle.
- Use meter stick to measure 0.2 m straight up.
- Lift bottle with scale up 0.2m and measure the force.
- Calculate the work done.
- Set up ramp using books and the wooden plank.
- Measure the rise.
- Measure the run.
- Calculate slope.
- Measure effort distance to the height desired.
- Mark height using a marker.
- Hook scale to bottle.
- Put bottle against ramp at the bottom.
- Pull it up at a steady rate using the scale.
- Get your partner to check how much force is being applied.
- Note down the force in computer.
- Calculate the work done.
- Repeat steps 5 through 16 four more times, with different slopes in every trial.
I think that the data we got from this table is not very reliable because we did not get a lot of similar data. The only similar data was when two of the trials got the same amount of work done. Ideally what should have happened was that the amount of work done should have been the same throughout the experiment, but only the force and distance changing. But in our experiment, the work changed at many places throughout the graph. I think this could have been because one of our variables was incorrect.
During the experiment, I made sure everything was done carefully. The bottle was the same mass all the time, the height was always 0.2 m, and we used the same scale for all the trials. But I think that the first trial might have gone wrong. This may have happened because we did it in a different place then the rest of the trials and we didn’t use books for the first trial as well. This means that the controlled variable might have changed. The last to trials could have gone wrong because the ramp was limited and we could not change the effort distance at a steady rate. I think another reason the data was wrong would be because we only measured everything once, and did not double check. This is probably a major thing in the experiments that did not allow us to get the results that we should have gotten.
I think that the experiment was not very fair because we changed location for half of the experiment and this could give us inaccurate data. I also think that the mass of the object was not controlled because we did the experiment and three different times and the bottle had to be that much emptied every time. We did empty it to the required mass, but I think it could have been a bit off the two other times.
If I got the chance to do this experiment again, I would make sure to use different ramps that are made specifically for that height. I would also do several trials and check multiple times so I can rule out the ones that are a bit different. I will also make sure to use the same things and not change position of where to do the experiment so accurate data can be collected. I would also use a sensitive weighing scale to measure the weight and mass. I will also keep comparing data with the sample data to see if the same data is received.
After I saw the sample data, I was confused why our data was so different than the sample data even though I made sure to not make mistakes. But then, I realized that there were many times and place where the experiment could have gone wrong. In the sample data, the work barely changes throughout the graph and different trials. This is because the force and the distance change so they equal out the work because w=fd. Our data was very different from the sample data. This was because we had many mistakes in the fairness and variables.
Here is how my graph looked and here is also the table of our data:
|Ramp 1:||Ramp 2:||Ramp 3:||Ramp 4:||Ramp 5:|
|Effort Distance (m)||0.75||0.60||0.45||0.30||0.20|
|Effort Force (n)||2||3||4||4.7||5|
Here is the sample data: