• Time taken will increase as distance increases. • Gravitational acceleration will be constant.
Conclusion Using the formula below or twice the slope of the graph, we can calculate g for any height.
g = 2s
___ t2
g = acceleration due to gravity (m s–2), s = distance fallen (m), t = time to fall (s)
Errors
The following errors should be considered when studying this experiment:
• parallax error in measuring distance • s too small, which gives rise to large percentage error
• electromagnet too sensitive as timer starts before ball has fully left
• scaler timer not accurate enough.
Precautions • Find the averages of distances and verify them with your lab partners.
• Use larger values of s to reduce percentage error. • Test that the timer starts only when the electromagnet has fully released the ball.
• Use the correct setting on the scaler timer to measure time (for example, set to ms).
Possible exam questions 1.
2. 3.
Why should s be as large as possible?
Why would the smallest value of time for each distance be used?
Why does twice the slope of the graph equal gravitational acceleration?
1.5 Verification of Boyle’s law Outline of experiment
In this experiment, we will prove Boyle’s law, using a Boyle’s law apparatus. Boyle’s law states that pressure is inversely proportional to volume
( P ∝ 1 __
V ) .
Once we have gathered measurements for pressure and its corresponding volume, we can record the data in a table and plot a graph of P against 1 Boyle’s law of proportionality.)
gas volume oil reservoir air pump pressure gauge tap
__ V . (This should be a straight-line graph through the origin, thus verifying
