GCSE · Physics · Edexcel · Spec 1PH0
Waves transfer energy not matter
A wave crosses the sea and nothing seems to arrive with it. So what exactly is the wave carrying?
Watch one spot, not the wave
The marked spot (position 4). The red line shows how far the water at position 4 is above or below its rest level. Watch it grow, shrink and drop below the rest level while the crest carries on past. That spot never slides along the surface.
Slide time forward. The crest runs along the surface, but the water at the marked spot just rises and falls.
Commit first
Picture a small paper boat floating out on the sea, right in the path of the waves.
A wave rolls in and passes right under the boat. Where is the boat once the wave has gone by?
Label the rope wave
Layers
Explore
Tap a label to light up that part. Peel the layers on and off.
The two directions meet at 90 degrees.
Four labels to learn. Tap each one.
At the shore
Reason it through
What does a wave actually deliver when it reaches a beach?
First link · your turn
Out at sea, what is the wave carrying forward?
WHAT YOU'VE LEARNED
A quick recap of today's lesson.
What really travels when a wave goes by?
What you need to know
- A wave transfers energy forwards. The material it passes through, such as water or rope (the medium), is not carried along.
- As a water wave passes, each small part of the water vibrates up and down about its rest position, which is the level of still, flat water.
- A floating object, a swimmer in the waves and a beach that never fills up all show that the water does not travel with the wave.
- Where waves arrive they can transfer their energy to other objects, for example making sand, pebbles and stones move on a beach.
- On a rope wave the vibrations are at right angles (90°) to the direction the wave travels, so the rope is not carried forward.
The big picture
A wave carries energy forward, but the water or rope it passes through is not carried along with it. Each small part just vibrates about its rest position while the wave moves on. When waves arrive, they can pass their energy on to other things, such as the sand and stones on a beach.
Key points
Worked example
Problem
A leaf floats on a pond. A wave crosses the pond and passes the leaf. A student says, "The wave pushes the leaf across the pond." Explain what really happens to the leaf, and say what the wave carries.
⚠ Watch out
Saying the water travels along with the wave. It does not: each part of the water vibrates up and down about its rest position, and what moves forward is energy.
Memory hook
Watch one spot, not the wave: the spot goes up and down, the energy goes on. Like a stadium wave, where everyone stays in their own seat. (That analogy only covers the staying-put bit.)
Check yourself
Cover the page and say it out loud: what travels along with a wave, what stays where it is, and what would you watch to prove it?
Flashcards
(8)What does a wave transfer?
What is the "medium" of a wave?
What is the rest position of the water in a wave?
In a water wave, what moves forward and what stays put?
Which spot should you watch to see what the water really does?
Name three pieces of evidence that water does not travel with a wave.
What happens when waves arrive at a beach?
On a rope wave, how does each part of the rope move compared with the wave?
Tap any card to flip it, or use Study as deck to go through them one at a time. In the full lesson these run as a spaced-repetition deck — you rate each card Hard, Good or Easy and the tricky ones keep coming back until they stick.
Learning with Lightbulb is opening soon
You can use this lesson now. Join the waitlist and we'll let you know when the full Lightbulb experience is ready.
Keep me postedMore Edexcel GCSE Physics topics
- Acceleration equation
- Acceleration of free fall g = 10 m/s^2
- Activity decreases over time
- Advantages of high-voltage transmission
- All bodies emit radiation: temperature dependence
- Ammeter in series
- Amplitude, period, wave velocity, wavefront
- Analyse energy stores in system changes
- Atmospheric pressure variation with height
- Atomic/nuclear changes generate radiation
- Background radiation
- Balancing nuclear equations
How this lesson was checked. This Edexcel GCSE Physics (specification 1PH0)lesson was published through Lightbulb Learning's human-designed editorial process — the educational standards, accuracy rules and publication checks it must pass were authored and approved by Philip Halpin. It passed subject-specific assessment, automated educational checks and technical publication verification before going live (publication checks completed 2 October 2026). Published pages are monitored, human spot-checking is ongoing across the lesson library, and anything found wrong is corrected or withdrawn. How our lessons are made and checked. Spotted a mistake? Email hello@lightbulblearning.co and we'll review it.