Most likely the students are using a crude measurement of time, like a stopwatch. They would get the best results with a scientific apparatus that uses a computer and optical sensors. Even recording their dropped objects with a video camera and analyzing the video would give more consistent results. Results will also vary greatly if different people are taking the time measures instead of one person making all measurements.
The conclusion is the gathering and understanding of the data that has been collected
Fossil fuel power burn carbon fuels such a coil,oil or gas to generate that drives large turbines that produces electricity by burning carbon fuel they produce large amount carbon dioxide.
