Automated measurement of speed
I can outline how radar guns in speed cameras are used to measure speed and use light gates to measure the speed of a moving object.
Automated measurement of speed
I can outline how radar guns in speed cameras are used to measure speed and use light gates to measure the speed of a moving object.
Lesson details
Key learning points
- A light gate measures the time for a card of a fixed length to pass through it.
- A radar gun measures changes in the frequency of reflected waves to measure speed.
- A motion sensor can use reflected ultrasonic wave timings to measure changes in distance to determine speed.
Common misconception
Travelling at exceptionally high speed through a speed camera means that it will not be able to measure your speed accurately and so it will not trigger.
Tell pupils that speed cameras use radio waves which travel at 300 000 000 m/s. They can accurately measure the speed of objects travelling at thousands of metres per second.
Keywords
Speed camera - A speed camera is used to measure speed of vehicles on roads. It captures images of any vehicle exceeding the speed limit of the road.
Radar gun - A radar gun uses shifts in the frequency of reflected radio waves to measure the speed of objects.
Light gate - A light gate can be used to measure speed. It uses an infrared beam to turn a timer on and off as an object passes through.
Content guidance
- Risk assessment required - equipment
Supervision
Adult supervision required
Licence
This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).
Video
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Starter quiz
6 Questions
car on a motorway -
70 mph
person walking -
1.5 m/s
snail moving across floor -
10 cm/minute
space station orbiting Earth -
7.7 km/s
sound wave in air -
330 m/s
Exit quiz
6 Questions
light gate -
sends signals to a timer when a passing object cuts its infrared beam
motion sensor -
sends out sound pulses and the reflections from an object are detected
radar gun -
uses changes in frequency of reflected waves to measure speed
speed camera -
takes photos of road vehicles a short time apart