Ticker timer: For the measurement of velocity and acceleration, using timing marks made on a moving paper tape by a vibrating ‘sticker’.
Things we need to prepare for an experiment: Ticker-timer Ticker-tape Counterweight Ruler
Steps: To put the Ticker-timer on the horizonal table top and fixed it. To connect the counterweight to the end of the ticker-tape. To open the Ticker-timer and make the counterweight free fall.
To choose the continuing three points and measure the distance between them, as S1. Calculate the V1=S1/2t. Following the steps above, the distance S2. Calculate the V2=S2/2t. We have V1 and V2, we have point out the number of the point, as n. So g=(V2-V1)/(n+1)t.
Reliable: This is reliable. The resistance can be reduced by a chain wheel. Also the weight of the counterweight can make us ignore resistant.
Errors: Systemic errors: There is air resistance. And the points on the Ticker-tape is not clear. Random errors: When we reading value of the distance between the points, we may measure a little different.