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29 Dec 2025
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Understanding Waves in National 5 Physics
charlotte
@charlotte_cxtgfaytiu
1 / 10
Physics Waves Overview
Waves are nature's way of moving energy from one place to another without moving matter itself. Think of throwing a stone into a pond - the ripples carry energy outward, but the water itself doesn't travel with the wave.
There are two main types you need to know. Transverse waves vibrate at right angles to the direction the energy travels - like waves on a string or electromagnetic waves (including light and radio). Longitudinal waves vibrate in the same direction as the energy transfer, with sound waves being the perfect example.
Quick Tip: Remember transverse = "T" for "across" (perpendicular), longitudinal = "L" for "lengthwise" (parallel).
The substance waves travel through is called the medium - this could be water, air, or even solid materials like steel.
Wave Characteristics and Measurements
Every wave has specific features you can measure. Amplitude is the height from the centre line to the peak - it tells you how much energy the wave carries. Wavelength (λ) is the distance between identical points on consecutive waves, like crest to crest.
Frequency measures how many waves pass a point each second, measured in hertz (Hz). A 5 Hz wave means 5 waves pass by every second. The period is simply how long one complete wave takes to pass - it's the opposite of frequency.
For transverse waves, these measurements are easy to spot on a diagram. With longitudinal waves, you measure between compressions (squeezed parts) instead of crests.
Exam Focus: You'll often need to count waves on diagrams and measure distances, so practice reading wave graphs carefully.
Frequency and Period Calculations
The relationship between frequency and period is straightforward: f = 1/T. As frequency increases, period decreases - they're inversely related. If you know one, you can always find the other.
Use f = N/t to calculate frequency when you know how many waves (N) pass in a certain time (t). For example, if 15 waves pass in 3 seconds, the frequency is 15 ÷ 3 = 5 Hz.
Period calculations are equally simple. A 1000 Hz sound wave has a period of 1/1000 = 0.001 seconds. High-frequency waves like radio signals have tiny periods, whilst low-frequency waves have longer periods.
Calculator Tip: For very small numbers, your calculator will show scientific notation (like 6.7 × 10⁻⁵), so get comfortable with this format.
Wave Speed and the Wave Equation
Wave speed uses the familiar distance-time relationship: v = d/t. But waves have a special equation that connects speed, frequency, and wavelength: v = fλ. This is probably the most important wave equation you'll use.
Here's the key insight: if wave speed stays constant, frequency and wavelength are inversely related. Double the frequency, and you halve the wavelength. It's like fitting more waves into the same space.
Practice rearranging the wave equation: v = fλ, f = v/λ, and λ = v/f. Most exam questions will give you two values and ask for the third.
Success Strategy: Always convert units first (mm to m, kHz to Hz) before plugging numbers into equations - it prevents most calculation errors.
Sound Waves and Speed
Sound is a longitudinal wave that needs particles to travel - that's why there's no sound in space! Sound travels through solids, liquids, and gases, but at very different speeds.
In air, sound travels at 340 m/s, but this changes with temperature and humidity. Sound moves much faster through solids like steel because particles are closer together, making energy transfer more efficient.
The classic experiment for measuring sound speed uses two microphones and an electronic timer. You measure the distance between microphones, time how long sound takes to travel between them, then use v = d/t.
Real-World Connection: This is why you see lightning before hearing thunder - light travels much faster than sound through air.
The data sheet in your exam will give you sound speeds for different materials, so you don't need to memorise them all.
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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 THE SCHOOLGPT. 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 THE SCHOOLGPT. 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 National 5 Physics
charlotte
@charlotte_cxtgfaytiu
Waves are everywhere around you - from the sound of your favourite music to the light from your phone screen. Understanding how waves work is crucial for grasping everything from earthquakes to radio signals, and it's simpler than you might... Show more
Physics Waves Overview
Waves are nature's way of moving energy from one place to another without moving matter itself. Think of throwing a stone into a pond - the ripples carry energy outward, but the water itself doesn't travel with the wave.
There are two main types you need to know. Transverse waves vibrate at right angles to the direction the energy travels - like waves on a string or electromagnetic waves (including light and radio). Longitudinal waves vibrate in the same direction as the energy transfer, with sound waves being the perfect example.
Quick Tip: Remember transverse = "T" for "across" (perpendicular), longitudinal = "L" for "lengthwise" (parallel).
The substance waves travel through is called the medium - this could be water, air, or even solid materials like steel.
Sign up to see the contentIt's free!
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Wave Characteristics and Measurements
Every wave has specific features you can measure. Amplitude is the height from the centre line to the peak - it tells you how much energy the wave carries. Wavelength (λ) is the distance between identical points on consecutive waves, like crest to crest.
Frequency measures how many waves pass a point each second, measured in hertz (Hz). A 5 Hz wave means 5 waves pass by every second. The period is simply how long one complete wave takes to pass - it's the opposite of frequency.
For transverse waves, these measurements are easy to spot on a diagram. With longitudinal waves, you measure between compressions (squeezed parts) instead of crests.
Exam Focus: You'll often need to count waves on diagrams and measure distances, so practice reading wave graphs carefully.
Sign up to see the contentIt's free!
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Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Frequency and Period Calculations
The relationship between frequency and period is straightforward: f = 1/T. As frequency increases, period decreases - they're inversely related. If you know one, you can always find the other.
Use f = N/t to calculate frequency when you know how many waves (N) pass in a certain time (t). For example, if 15 waves pass in 3 seconds, the frequency is 15 ÷ 3 = 5 Hz.
Period calculations are equally simple. A 1000 Hz sound wave has a period of 1/1000 = 0.001 seconds. High-frequency waves like radio signals have tiny periods, whilst low-frequency waves have longer periods.
Calculator Tip: For very small numbers, your calculator will show scientific notation (like 6.7 × 10⁻⁵), so get comfortable with this format.
Sign up to see the contentIt's free!
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Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Wave Speed and the Wave Equation
Wave speed uses the familiar distance-time relationship: v = d/t. But waves have a special equation that connects speed, frequency, and wavelength: v = fλ. This is probably the most important wave equation you'll use.
Here's the key insight: if wave speed stays constant, frequency and wavelength are inversely related. Double the frequency, and you halve the wavelength. It's like fitting more waves into the same space.
Practice rearranging the wave equation: v = fλ, f = v/λ, and λ = v/f. Most exam questions will give you two values and ask for the third.
Success Strategy: Always convert units first (mm to m, kHz to Hz) before plugging numbers into equations - it prevents most calculation errors.
Sign up to see the contentIt's free!
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Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Sound Waves and Speed
Sound is a longitudinal wave that needs particles to travel - that's why there's no sound in space! Sound travels through solids, liquids, and gases, but at very different speeds.
In air, sound travels at 340 m/s, but this changes with temperature and humidity. Sound moves much faster through solids like steel because particles are closer together, making energy transfer more efficient.
The classic experiment for measuring sound speed uses two microphones and an electronic timer. You measure the distance between microphones, time how long sound takes to travel between them, then use v = d/t.
Real-World Connection: This is why you see lightning before hearing thunder - light travels much faster than sound through air.
The data sheet in your exam will give you sound speeds for different materials, so you don't need to memorise them all.
Sign up to see the contentIt's free!
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Sign up to see the contentIt's free!
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Sign up to see the contentIt's free!
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Sign up to see the contentIt's free!
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Sign up to see the contentIt's free!
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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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4.8/5
Google Play
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 THE SCHOOLGPT. 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 THE SCHOOLGPT. 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