Measuring the Gravitational Acceleration
1. Aim:
The aim of the experiment was to record and measure the earth's gravitational acceleration at the surface of the earth, using ticker timer, ticker tape and carbon disc to gather results.
2. Equipment Used:
Ticker Timer
Ticker Tape
Carbon Disc
Weight
Sticky Tape
F Clamp
12V AC Power Supply
Ruler
Pen
Bench
Spread sheet Software
3. Method
The mass (weight) was fixed to one end of the ticker tape using a piece of sticky tape. The ticker timer was hold in place by a clamp. Also it was connected to the power supply. The ticker timer was used on its side to reduce the friction between the tape and the timer. The tape was then fitted into the timer, as the class was divided in pair, one student held onto the free end of the tape and switched on the power supply. By releasing the tape the pull of gravity on the mass accelerated the tape through the timer. The experiment could be repeated further times for more data collection and possibly accurate result.
Once the ticker tape was marked it was laid flat on a bench for data analyse. The distance between dots on the marked ticker tape represents the weight’s position change during that time interval. A large distance between dots indicates that the weight was moving fast during that time interval. The distance between any set of dots represent a time interval of 0.02 seconds given by 1 second over 50 Hz. Starting with second dot from the cluster at the start, reference points were marked for every fifth dot to the end of the tape. Once the reference points were marked, the velocity was calculated by measuring the distance of two sections span (one dot before and one after a reference point) over the time period of two sets of dots 0.04 seconds (one set of dots time interval is 0.02 seconds). After the velocity was calculated, time and velocity data were entered onto the spreadsheet. The slope of treading line graph generated by the spreadsheet software calculated the gravitational acceleration.
4. Results
The following data was collected on the afternoon of Thursday 7th May 2015. Note: due to equipment malfunction the results from the first run were discarded.
4.1. Table 1 – Second Run
Time (s)