Synchronisation is the process of ensuring two (or more) things happen at the same time.

The period of a wave is the time taken for one oscillation.

The wavelength  of a wave is the distance a wave travels during one period.

A result is accurate if it is close to the true value.

A systematic error affects all results by the same amount.

Measuring the speed of sound in air and solids

Physics

In the Electromagnetic waves unit, they will build on this knowledge to learn about the reflection and refraction of light, other types of electromagnetic radiation in the EM spectrum and the helpful and harmful effects of each type of radiation.

In the Waves unit, pupils learnt about the properties and propagation of transverse and longitudinal waves.

Measuring waves

Physical activity and equipment requiring safe use

Give the missing number in the following sentence. The accepted value for the speed of sound in air is {{}} m/s.

If repeat measurements cluster closely together in a small range

If it is repeatable and precise, and has been checked for random errors

If it is repeatable and reproducible, and has been checked for systematic errors

Which two of the below would allow a result to be considered accurate?

Use a trundle wheel to measure a distance of at least 100m from a vertical wall.

Two people should stand at that distance from the wall.

One person should make a sudden noise, the other starts a timer at the same time

The timer should be stopped when the echo is heard.

The speed of sound is calculated using (2 x distance to the wall)/time taken

Starting with the measurement of distance, put the steps for the echo method of measuring the speed of sound into the correct order. 

Andeep and Sofia are 100 m from a wall. Andeep makes a sound, Sofia measures the time for the echo to return as 0.64 s. Their result for the speed of sound, to 2 significant figures, is {{}} m/s.

Measure the length of the rod (L) with a meter rule. Wavelength will be 2L.

Suspend the rod using elastic bands and strike the end so the bar rings.

Use a frequency-meter to determine the frequency of the rod's oscillations.

Calculate the speed of sound in the bar by multiplying frequency and wavelength.

Starting with the measurement of the rod length, put the steps for the method of measuring the speed of sound in a metal rod into the correct order. 

Alex and Jun suspend a 1.20 m long metal rod on elastic bands. Jun strikes the rod and Alex uses a phone app to find the frequency of the sound: 2675 Hz. The speed of sound in the rod is {{}} m/s.

When a person repeats a word over and over again

When sound waves reflect back so a sound is heard more than once

When a sound wave is absorbed into the air so it can be heard for a longer time

The material or substance that a wave is travelling through is called the wave {{}}.

A wave has a frequency of 2 Hz and a wavelength of 10 m. What is the wave speed?

The time taken for one oscillation is called the {{}} of a wave.

the distance from one peak to the next peak

the distance from one trough to the next trough

the distance from one part of a wave to the same part of the next wave

the distance travelled by a wave during one period

Which one of these does not describe the wavelength of a wave?

Which word means a result is close to the true value?

Content guidance

Risk assessment required - equipment

Adult supervision required

This lesson will soon be taken down.

Measuring the speed of sound in air and solids

Lesson outcome

Content guidance