Water Waves

In this worksheet, students will be introduced to water waves as undulations, which travel through water in a transverse motion, and can add to or cancel out themselves.

Key stage:  KS 3

Curriculum topic:   Physics: Waves

Curriculum subtopic:   Observed Waves

Difficulty level:

QUESTION 1 of 10

The diagram shows the characteristics of transverse and longitudinal waves. Light and water waves, although very different to each other, travel as transverse waves. In transverse waves, the vibrations are at a right angle to the direction of movement. The number of waves that pass through a certain point in one second is called the frequency of a wave.

The pictures below show water waves.

If you drop a stone or a water droplet on a smooth water surface, ripples will form (see picture below).

When two waves occur in the same medium (the substance they travel in) at the same time, they interfere with each other and can combine. In essence, they can add up or cancel each other out; a bit like addition and subtraction.

Wave interference and superposition (sometimes called superimposition) is shown in the diagram below:

In constructive interference the two waves add up to form a higher wave (shown by the green wave). In destructive interference (also called superposition), the two waves cancel each other out, which is shown by the flat line.

It is indeed very interesting that despite wave interference, the waves themselves do not change and after the superposition, they will continue travelling as they were before and on the same path.

Tick two examples of transverse waves.

light

water

sound

Is this statement true or false?

In longitudinal waves, the vibrations are at a right angle to the direction of the movement.

true

false

What forms when you drop a stone on a smooth water surface?

Tick three possible outcomes of two waves travelling in the same medium.

extension

superposition

constructive effect

cancellation

Tick two other words for superposition.

interference

superimposition

combination

extension

The diagram shows two waves travelling in the same direction:

What will happen when the two waves travel in the same medium?

They will cancel each other out.

They will add to each other.

The resultant wave will have a higher amplitude.

The diagram shows two waves.

What will happen when the two waves travel in the same medium?

They will cancel each other out.

They will combine.

They will result in a wave with a higher amplitude.

The diagram shows two waves.

What will happen when the two waves travel in the same medium? Draw the wave on a piece of paper and compare it with the correct answer in the explanation section.

They will cancel each other out.

They will combine.

They will result in a wave with a lower amplitude.

What is the definition of wave frequency?

The number of waves.

The number of waves that pass through an area in one minute.

The number of waves that pass through a certain point in one second.

Is this statement true or false?

After wave interference, the waves continue travelling as a combined wave.

true

false

• Question 1

Tick two examples of transverse waves.

light
water
EDDIE SAYS
Light and water waves are transverse waves, whereas sound is a longitudinal wave.
• Question 2

Is this statement true or false?

In longitudinal waves, the vibrations are at a right angle to the direction of the movement.

false
EDDIE SAYS
The statement is false; the vibrations are at a right angle to the direction of the movement in transverse waves.
• Question 3

What forms when you drop a stone on a smooth water surface?

ripples
EDDIE SAYS
When you drop a stone on a smooth water surface, ripples form.
• Question 4

Tick three possible outcomes of two waves travelling in the same medium.

superposition
cancellation
EDDIE SAYS
Superposition occurs when two waves travel in the same medium. This includes addition or cancellation of the waves.
• Question 5

Tick two other words for superposition.

interference
superimposition
EDDIE SAYS
Superposition is also called superimposition or interference.
• Question 6

The diagram shows two waves travelling in the same direction:

What will happen when the two waves travel in the same medium?

They will add to each other.
The resultant wave will have a higher amplitude.
EDDIE SAYS
They will add to each other and the resultant wave will have a higher amplitude.
• Question 7

The diagram shows two waves.

What will happen when the two waves travel in the same medium?

They will cancel each other out.
EDDIE SAYS
They will cancel each other out.
• Question 8

The diagram shows two waves.

What will happen when the two waves travel in the same medium? Draw the wave on a piece of paper and compare it with the correct answer in the explanation section.

They will combine.
EDDIE SAYS
They will combine and result in a wave with a combined amplitude.
• Question 9

What is the definition of wave frequency?

The number of waves that pass through a certain point in one second.
EDDIE SAYS
Wave frequency is defined as the number of waves that pass through a certain point in one second.
• Question 10

Is this statement true or false?

After wave interference, the waves continue travelling as a combined wave.

false
EDDIE SAYS
The statement is false; after wave interference, the waves continue travelling as they were before the interference.
---- OR ----

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