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25 Jan 2026
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Understanding Waves in GCSE Physics
Ella Biggins
@ellabiggins
1 / 5
Wave Types and Properties
Ever wonder why sound travels through walls but light doesn't? It all comes down to wave types. Longitudinal waves have vibrations that move parallel to the direction the wave travels - think of a slinky being pushed and pulled. Sound waves work this way, creating compressions (squashed bits) and rarefactions (stretched bits) in the air.
Transverse waves are completely different - their vibrations move perpendicular (at right angles) to the wave's direction. Picture a guitar string vibrating up and down while the wave energy moves along the string. These waves have clear crests (peaks) and troughs (dips).
The key difference? Longitudinal waves vibrate parallel to energy transfer, while transverse waves vibrate perpendicular to it. This simple rule helps you identify any wave type you encounter.
Quick Tip: Remember "T for Transverse = T for Top and bottom movement" - the vibrations go up and down while the wave goes forward!
Mechanical vs Electromagnetic Waves
Not all waves are created equal! Mechanical waves are like that friend who needs constant support - they must have a medium (material) to travel through. Water waves need water, sound waves need air, and shock waves need solid materials.
Electromagnetic waves are the independent ones - they create their own electrical and magnetic energy to travel through empty space. Light, microwaves, and gamma rays all belong to this group.
When waves hit boundaries between different materials, three things can happen: absorption (energy gets soaked up), reflection (waves bounce back), or transmission (waves continue through but often bend). This bending process is called refraction - it's why a straw looks bent in a glass of water.
Wave speed, wavelength, amplitude, frequency, and period are your essential wave vocabulary. Master these terms and you'll understand how waves behave in any situation.
Remember: Mechanical waves are needy (need a medium), electromagnetic waves are independent (travel through space)!
The Electromagnetic Spectrum
The electromagnetic spectrum is like a massive family of waves, all related but with different personalities. From radio waves (longest wavelength) to gamma rays (shortest wavelength), each type has unique properties and uses.
Here's the danger rule: shorter wavelengths = more dangerous. The most hazardous waves are ultraviolet, X-rays, and gamma rays because they pack serious energy. Radio waves and visible light? Pretty harmless for everyday exposure.
Electromagnetic waves form when electrons in atoms get excited and jump to higher energy levels, then fall back down and release energy. Gamma rays are special - they come from changes in atomic nuclei, usually when radioactive atoms decay and need to dump extra energy.
Infrared radiation heats objects that absorb it. Matt black surfaces are brilliant absorbers, while shiny surfaces reflect most radiation away. This is why car dashboards get scorching hot in summer but mirrors stay relatively cool.
Safety Note: The shorter the wavelength, the more dangerous the wave - remember this for UV exposure and medical procedures!
Practical Uses of EM Waves
Radio waves are communication superstars. Long radio waves can travel around Earth's curved surface by diffracting around obstacles, while short waves bounce off the ionosphere to reach distant places. This is how radio stations broadcast globally.
Microwaves power both satellite TV and your kitchen appliances, but they use different wavelengths. Satellite microwaves travel to space and back (causing slight delays), while microwave ovens use waves that water molecules love to absorb, heating your food from the inside out.
Infrared cameras detect heat by measuring IR radiation - the hotter an object, the more infrared it emits. Electrical heaters work by emitting infrared that gets absorbed by objects and air in your room.
Fibre optic cables use visible light to transmit internet data. Light pulses bounce back and forth inside thin glass fibres using reflection, carrying information over huge distances without getting absorbed or scattered.
Tech Fact: Your microwave oven and satellite dish both use microwaves, but completely different wavelengths - that's why your phone doesn't interfere with your dinner!
Medical Applications and Safety
Ultraviolet radiation gives you that summer tan, but overexposure causes premature skin aging and increases cancer risk. UV lamps in tanning salons and security pens (invisible ink that glows under UV) use this same radiation type.
X-rays and gamma rays are medical game-changers. X-rays pass through soft tissue but get blocked by bones and metal, creating those familiar skeleton images. Both X-rays and gamma rays can kill cancer cells when carefully directed, and gamma rays work as medical tracers to follow processes inside your body.
The danger factor is real though. UV radiation damages surface cells, while X-rays and gamma rays are ionising radiation - they carry enough energy to knock electrons off atoms, potentially killing cells or causing gene mutations.
CT scans use X-rays and computers to build detailed body pictures. Interestingly, a chest CT scan is four times more likely to cause harm than a head scan. This is why radiographers wear lead aprons and hide behind screens during procedures.
Safety Reality: Medical staff protect themselves from radiation exposure because even helpful radiation can be harmful with repeated exposure!
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Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
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This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
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The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
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In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
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very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
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I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
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THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE Knowunity AI. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE Knowunity AI. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
Understanding Waves in GCSE Physics
Ella Biggins
@ellabiggins
Waves are everywhere around us - from the sound of your voice to the light from your phone screen. Understanding how different types of waves work and behave is crucial for your physics studies and helps explain loads of everyday... Show more
Wave Types and Properties
Ever wonder why sound travels through walls but light doesn't? It all comes down to wave types. Longitudinal waves have vibrations that move parallel to the direction the wave travels - think of a slinky being pushed and pulled. Sound waves work this way, creating compressions (squashed bits) and rarefactions (stretched bits) in the air.
Transverse waves are completely different - their vibrations move perpendicular (at right angles) to the wave's direction. Picture a guitar string vibrating up and down while the wave energy moves along the string. These waves have clear crests (peaks) and troughs (dips).
The key difference? Longitudinal waves vibrate parallel to energy transfer, while transverse waves vibrate perpendicular to it. This simple rule helps you identify any wave type you encounter.
Quick Tip: Remember "T for Transverse = T for Top and bottom movement" - the vibrations go up and down while the wave goes forward!
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Improve your grades
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By signing up you accept Terms of Service and Privacy Policy
Mechanical vs Electromagnetic Waves
Not all waves are created equal! Mechanical waves are like that friend who needs constant support - they must have a medium (material) to travel through. Water waves need water, sound waves need air, and shock waves need solid materials.
Electromagnetic waves are the independent ones - they create their own electrical and magnetic energy to travel through empty space. Light, microwaves, and gamma rays all belong to this group.
When waves hit boundaries between different materials, three things can happen: absorption (energy gets soaked up), reflection (waves bounce back), or transmission (waves continue through but often bend). This bending process is called refraction - it's why a straw looks bent in a glass of water.
Wave speed, wavelength, amplitude, frequency, and period are your essential wave vocabulary. Master these terms and you'll understand how waves behave in any situation.
Remember: Mechanical waves are needy (need a medium), electromagnetic waves are independent (travel through space)!
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
The Electromagnetic Spectrum
The electromagnetic spectrum is like a massive family of waves, all related but with different personalities. From radio waves (longest wavelength) to gamma rays (shortest wavelength), each type has unique properties and uses.
Here's the danger rule: shorter wavelengths = more dangerous. The most hazardous waves are ultraviolet, X-rays, and gamma rays because they pack serious energy. Radio waves and visible light? Pretty harmless for everyday exposure.
Electromagnetic waves form when electrons in atoms get excited and jump to higher energy levels, then fall back down and release energy. Gamma rays are special - they come from changes in atomic nuclei, usually when radioactive atoms decay and need to dump extra energy.
Infrared radiation heats objects that absorb it. Matt black surfaces are brilliant absorbers, while shiny surfaces reflect most radiation away. This is why car dashboards get scorching hot in summer but mirrors stay relatively cool.
Safety Note: The shorter the wavelength, the more dangerous the wave - remember this for UV exposure and medical procedures!
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Practical Uses of EM Waves
Radio waves are communication superstars. Long radio waves can travel around Earth's curved surface by diffracting around obstacles, while short waves bounce off the ionosphere to reach distant places. This is how radio stations broadcast globally.
Microwaves power both satellite TV and your kitchen appliances, but they use different wavelengths. Satellite microwaves travel to space and back (causing slight delays), while microwave ovens use waves that water molecules love to absorb, heating your food from the inside out.
Infrared cameras detect heat by measuring IR radiation - the hotter an object, the more infrared it emits. Electrical heaters work by emitting infrared that gets absorbed by objects and air in your room.
Fibre optic cables use visible light to transmit internet data. Light pulses bounce back and forth inside thin glass fibres using reflection, carrying information over huge distances without getting absorbed or scattered.
Tech Fact: Your microwave oven and satellite dish both use microwaves, but completely different wavelengths - that's why your phone doesn't interfere with your dinner!
Sign up to see the contentIt's free!
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Improve your grades
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Medical Applications and Safety
Ultraviolet radiation gives you that summer tan, but overexposure causes premature skin aging and increases cancer risk. UV lamps in tanning salons and security pens (invisible ink that glows under UV) use this same radiation type.
X-rays and gamma rays are medical game-changers. X-rays pass through soft tissue but get blocked by bones and metal, creating those familiar skeleton images. Both X-rays and gamma rays can kill cancer cells when carefully directed, and gamma rays work as medical tracers to follow processes inside your body.
The danger factor is real though. UV radiation damages surface cells, while X-rays and gamma rays are ionising radiation - they carry enough energy to knock electrons off atoms, potentially killing cells or causing gene mutations.
CT scans use X-rays and computers to build detailed body pictures. Interestingly, a chest CT scan is four times more likely to cause harm than a head scan. This is why radiographers wear lead aprons and hide behind screens during procedures.
Safety Reality: Medical staff protect themselves from radiation exposure because even helpful radiation can be harmful with repeated exposure!
We thought you’d never ask...
What is the Knowunity AI companion?
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
Where can I download the Knowunity app?
You can download the app from Google Play Store and Apple App Store.
Is Knowunity really free of charge?
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
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The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE Knowunity AI. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE Knowunity AI. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user