Core Practical 1: Investigating Motion
Aim of the Experiment
- The aim of this experiment is to investigate the motion of some everyday objects, such as:
- A paper cone
- A tennis ball
- This is just one method of carrying out this experiment - some methods involve the use of light gates to measure speed and acceleration, e.g. for a toy car moving down a slope
- Independent variable = Distance, d
- Dependent variable = Time, t
- Control variables:
- Use the same object (paper cone, tennis ball etc.) for each measurement
Equipment List
- Resolution of measuring equipment:
- Ruler = 1 mm
- Stop clock = 0.01 s
Method
Investigating the motion of a falling paper cone
- Measure out a height of 1.0 m using the tape measure or metre ruler
- Drop the object (paper cone or tennis ball) from this height, which is the distance travelled by the object
- Use the stop clock to measure how long the object takes to travel this distance
- Record the distance travelled and time taken
- Repeat steps 2-3 three times, calculating an average time taken for the object to fall a certain distance
- Repeat steps 1-4 for heights of 1.2 m, 1.4 m, 1.6 m, and 1.8 m
- An example table of results might look like this:
Analysis of Results
- The average speed of the falling object can be calculated using the equation:
- Where:
- Average speed is measured in metres per second (m/s)
- Distance moved is measured in metres (m)
- Time taken is measured in seconds (s)
- Therefore, calculate the average speed at each distance by dividing the distance by the average time taken
Evaluating the Experiment
Systematic Errors:
- Make sure the measurements on the tape measure or metre rule are taken at eye level to avoid parallax error
- Consider using an electronic sensor, such as light gates, to obtain highly accurate measurements of time
- Once the object is released, the timer starts and stops automatically as it reaches the sensor on the ground
- Ensure the experiment is done in a space with no draught or breeze, as this could affect the motion of the falling object
- Using a ball bearing and an electronic data logger, like a trap door, is a good way to remove the error due to human reaction time for this experiment
Safety Considerations
- Place a mat or a soft material below any falling object to cushion its fall