14
Simple Harmonic Motion
Subject: Physics
Sensor: SmartEye sensor
Aim:
To show how the length of a pendulum affects the Time Period.
Overview:
The Time Period is the time taken for a pendulum to swing from one side to the other and back again. By keeping the mass of the pendulum bob
constant, the length of the pendulum can be altered and the time period measured.
Equipment required:
LogIT Voyager.
1 SmartEye light sensor.
Matt black card.
Light source such as torch, lamp or similar.
Mass and holder (could be modelling clay).
String to make pendulum.
Clamp stands.
Hazards:
Children should be supervised at all times.
If clamp stands are used to hold the pendulum, make sure they are not mounted above pupils.
Always check your local regulations or the school advisory service such as CLEAPSS or SSERC
for guidance on the use of any hazardous material or source.
Setup:
1. Set up a 2m length of string and attach the mass to the end.
2. Make a small tube of black card by wrapping a small slip of card around a pencil such that the
width is at least the width of the SmartEye sensor. (Approx. 1cm diam.)
3. Place the tube over the pendulum and place Voyager such that the SmartEye is close to the swinging tube. (See photo).
4. Place the light source opposite the SmartEye sensor forming a light ‘gate’.
5. Connect Voyager to the computer, start the datalogging software, select the timing function and select ‘Simple Harmonic Motion’.
Note: The Voyager can be used with a clamp stand or simply placed on text books. If using clamp stands, do not clamp Voyager too tightly.
Ensure that the light source shines into the SmartEye as this change in contrast between the light source and black card will allow Voyager to
‘see’ the card passing.
