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9 Dec 2025
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GCSE AQA Energy Revision Notes
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Energy and Its Forms
Your world runs on energy transfers - every time something moves, heats up, or changes, energy is moving from one form to another. A system can be a single object (like a bouncing ball) or multiple objects working together (like a car engine).
Kinetic energy is the energy of movement, calculated using: KE = 0.5 × mass × speed². This means a faster-moving object has much more kinetic energy because speed is squared in the equation.
When you stretch a spring or elastic band, you're storing elastic potential energy using: EPE = 0.5 × spring constant × extension². The spring constant tells you how stiff the spring is.
Gravitational potential energy increases when you lift something higher: GPE = mass × gravitational field strength × height. That's why dropping something from greater heights creates more impact.
Quick Tip: Remember that all these energies are measured in joules (J), and mass is always in kilograms, not grams!
Power and Energy Conservation
Power measures how quickly energy transfers happen - it's energy per second, measured in watts. The equations are straightforward: power = energy transferred ÷ time, or power = work done ÷ time.
Here's the most important physics rule you'll ever learn: energy cannot be created or destroyed, only transferred or stored differently. In any closed system, the total energy stays exactly the same.
However, energy often gets "wasted" through dissipation - usually as unwanted heat or sound. You can reduce this waste through lubrication (less friction), streamlining (less air resistance), thermal insulation, and reducing electrical resistance.
Thermal conductivity determines how quickly heat travels through materials. Thick walls with low thermal conductivity (like brick with insulation) keep buildings warm, whilst thin walls with high thermal conductivity (like metal) let heat escape rapidly.
Efficiency tells you how good a device is at avoiding waste: efficiency = useful energy output ÷ total energy input. Perfect efficiency (100%) is impossible in real life.
Real-world connection: Your phone battery getting warm whilst charging shows energy dissipation in action!
Energy Resources and Environmental Impact
The electricity in your home comes from various energy resources, each with different advantages and problems. Renewable sources include solar power, wind turbines, hydroelectric dams, tidal power, wave power, geothermal energy, and biofuels.
Non-renewable sources are fossil fuels (coal, oil, natural gas) and nuclear fuel. Fossil fuels release carbon dioxide when burned, contributing to climate change. Nuclear power produces dangerous radioactive waste that remains hazardous for thousands of years.
Different energy resources suit different uses: electricity generation uses fossil fuels, nuclear, and renewables; heating often relies on gas boilers or renewable alternatives; transport mainly uses petrol/diesel but electric vehicles are becoming more common.
Environmental impacts vary significantly between energy sources. Fossil fuels cause global warming through CO₂ emissions. Wind farms can create noise pollution and affect wildlife. Hydroelectric dams destroy habitats but produce clean electricity. Solar and wind power depend on weather, making them unreliable.
Energy trends show society moving away from fossil fuels toward renewables, though this transition faces challenges including cost, reliability, and infrastructure requirements.
Think about it: Every energy choice involves trade-offs between environmental impact, cost, and reliability - there's no perfect solution!
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Stefan S
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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
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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
GCSE AQA Energy Revision Notes
G
G
@gurneet
Energy is everywhere around you - from the movement of your phone when you drop it to the electricity powering your home. Understanding how energy works, transfers, and changes form is essential for GCSE Physics and helps explain everything from... Show more
Energy and Its Forms
Your world runs on energy transfers - every time something moves, heats up, or changes, energy is moving from one form to another. A system can be a single object (like a bouncing ball) or multiple objects working together (like a car engine).
Kinetic energy is the energy of movement, calculated using: KE = 0.5 × mass × speed². This means a faster-moving object has much more kinetic energy because speed is squared in the equation.
When you stretch a spring or elastic band, you're storing elastic potential energy using: EPE = 0.5 × spring constant × extension². The spring constant tells you how stiff the spring is.
Gravitational potential energy increases when you lift something higher: GPE = mass × gravitational field strength × height. That's why dropping something from greater heights creates more impact.
Quick Tip: Remember that all these energies are measured in joules (J), and mass is always in kilograms, not grams!
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Power and Energy Conservation
Power measures how quickly energy transfers happen - it's energy per second, measured in watts. The equations are straightforward: power = energy transferred ÷ time, or power = work done ÷ time.
Here's the most important physics rule you'll ever learn: energy cannot be created or destroyed, only transferred or stored differently. In any closed system, the total energy stays exactly the same.
However, energy often gets "wasted" through dissipation - usually as unwanted heat or sound. You can reduce this waste through lubrication (less friction), streamlining (less air resistance), thermal insulation, and reducing electrical resistance.
Thermal conductivity determines how quickly heat travels through materials. Thick walls with low thermal conductivity (like brick with insulation) keep buildings warm, whilst thin walls with high thermal conductivity (like metal) let heat escape rapidly.
Efficiency tells you how good a device is at avoiding waste: efficiency = useful energy output ÷ total energy input. Perfect efficiency (100%) is impossible in real life.
Real-world connection: Your phone battery getting warm whilst charging shows energy dissipation in action!
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
Energy Resources and Environmental Impact
The electricity in your home comes from various energy resources, each with different advantages and problems. Renewable sources include solar power, wind turbines, hydroelectric dams, tidal power, wave power, geothermal energy, and biofuels.
Non-renewable sources are fossil fuels (coal, oil, natural gas) and nuclear fuel. Fossil fuels release carbon dioxide when burned, contributing to climate change. Nuclear power produces dangerous radioactive waste that remains hazardous for thousands of years.
Different energy resources suit different uses: electricity generation uses fossil fuels, nuclear, and renewables; heating often relies on gas boilers or renewable alternatives; transport mainly uses petrol/diesel but electric vehicles are becoming more common.
Environmental impacts vary significantly between energy sources. Fossil fuels cause global warming through CO₂ emissions. Wind farms can create noise pollution and affect wildlife. Hydroelectric dams destroy habitats but produce clean electricity. Solar and wind power depend on weather, making them unreliable.
Energy trends show society moving away from fossil fuels toward renewables, though this transition faces challenges including cost, reliability, and infrastructure requirements.
Think about it: Every energy choice involves trade-offs between environmental impact, cost, and reliability - there's no perfect solution!
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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Can't find what you're looking for? Explore other subjects.
Students love us — and so will you.
4.9/5
App Store
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