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Britain & the wider world: 1745 -1901
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Physics
7 Dec 2025
332
6 pages
Reuben Cowell @reubencowell
Ever wondered how energy moves around in the world? In physics, energy never actually disappears - it just... Show more
Your phone battery, a bouncing ball, and even your hot cup of tea all have one thing in common - they're storing energy in different ways. There are eight energy stores you need to master for your exams.
Thermal energy exists because of temperature, whilst kinetic energy appears when objects move. Gravitational potential energy builds up when you lift something high, and elastic potential energy gets stored in stretched springs or rubber bands.
The remaining four are chemical energy (found in food, fuel, and batteries), magnetic energy (between magnets), electrostatic energy (between charged objects), and nuclear energy (locked inside atoms). Once you recognise these stores, you'll start spotting them everywhere in exam questions.
Quick Tip Think of energy stores like different bank accounts - energy moves between them but the total amount stays the same!
Energy doesn't teleport between stores - it needs specific pathways to move around. There are four main transfer methods that crop up constantly in your physics papers.
Heating transfers energy from hot objects to cooler ones, like when a kettle's element warms up water. Doing work happens when forces move objects or when electrical current flows - think throwing a ball or a car accelerating.
Radiation moves energy through electromagnetic waves (like light warming your face), whilst electrical transfer occurs when current flows through circuits. Understanding these pathways helps you tackle energy problems systematically.
When objects fall, energy shifts from their gravitational potential energy store to their kinetic energy store. In reality, air resistance means some energy also transfers to thermal stores in the surrounding air.
Remember A system can be a single object or multiple objects you're focusing on - energy can transfer into it, out of it, or between different parts within it.
Here's the golden rule that'll save you marks in every energy question the total energy in a closed system never changes. This means energy can't be created or destroyed, only moved around.
A closed system is one where neither matter nor energy can enter or leave - think of it like a sealed box. Even when dramatic changes happen inside, the total energy remains constant.
This principle helps you solve problems systematically. If a ball loses gravitational potential energy whilst falling, it must gain exactly the same amount of kinetic energy (ignoring air resistance). The numbers always balance out.
Exam Strategy When stuck on energy questions, list what energy stores increase and decrease - they must equal each other!
Time for the maths bit - but don't worry, these equations are your friends once you practise them. Kinetic energy calculations pop up constantly, so memorise this formula Ek = ½mv².
The equation tells you that doubling an object's speed actually quadruples its kinetic energy (because you're squaring the velocity). Mass matters too - heavier objects store more kinetic energy at the same speed.
For elastic potential energy, use Ee = ½ke². Here, 'k' represents the spring constant (how stiff the spring is), whilst 'e' shows how much you've stretched it. Stretch a spring twice as far, and you store four times more energy.
Gravitational potential energy uses the simpler formula Ep = mgh. This one's straightforward - more mass, greater height, or stronger gravity all mean more stored energy.
Calculator Tip Watch out for that ½ in the kinetic and elastic energy equations - it's easy to forget under exam pressure!
Different materials need different amounts of energy to heat up - this property is called specific heat capacity. Water needs loads of energy to warm up, which is why the sea stays cool in summer and warm in winter.
Specific heat capacity measures how much energy you need to raise 1kg of a substance by 1°C. Materials with high specific heat capacities are excellent for storing thermal energy - that's why water works brilliantly in central heating systems.
The formula ΔE = mcΔθ connects energy transfer to temperature changes. 'ΔE' represents energy change, 'm' is mass, 'c' is specific heat capacity, and 'Δθ' shows temperature change.
This equation works both ways - heating up and cooling down. When substances cool, they release exactly the same amount of energy they absorbed when warming up.
Real-world Connection Metal car seats heat up quickly in summer (low specific heat capacity), whilst the plastic dashboard stays cooler (higher specific heat capacity).
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.
You can download the app from Google Play Store and Apple App Store.
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
7
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Work and Energy explanation. Work done by a constant force. Work done by a variable force.
AP Physics 1Formulas, concepts of work, practice problem, and kinetic energy
AP Physics 1A presentation and discussion of the concepts of power, work, and energy.
AP Physics 1This describes a fundamental physics concept.
AP Physics 1Quotes from every main character
English LiteratureApp Store
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
Reuben Cowell
@reubencowell
Ever wondered how energy moves around in the world? In physics, energy never actually disappears - it just keeps moving between different places and changing forms. Understanding energy stores and transfers is crucial for your GCSE physics success.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Your phone battery, a bouncing ball, and even your hot cup of tea all have one thing in common - they're storing energy in different ways. There are eight energy stores you need to master for your exams.
Thermal energy exists because of temperature, whilst kinetic energy appears when objects move. Gravitational potential energy builds up when you lift something high, and elastic potential energy gets stored in stretched springs or rubber bands.
The remaining four are chemical energy (found in food, fuel, and batteries), magnetic energy (between magnets), electrostatic energy (between charged objects), and nuclear energy (locked inside atoms). Once you recognise these stores, you'll start spotting them everywhere in exam questions.
Quick Tip: Think of energy stores like different bank accounts - energy moves between them but the total amount stays the same!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Energy doesn't teleport between stores - it needs specific pathways to move around. There are four main transfer methods that crop up constantly in your physics papers.
Heating transfers energy from hot objects to cooler ones, like when a kettle's element warms up water. Doing work happens when forces move objects or when electrical current flows - think throwing a ball or a car accelerating.
Radiation moves energy through electromagnetic waves (like light warming your face), whilst electrical transfer occurs when current flows through circuits. Understanding these pathways helps you tackle energy problems systematically.
When objects fall, energy shifts from their gravitational potential energy store to their kinetic energy store. In reality, air resistance means some energy also transfers to thermal stores in the surrounding air.
Remember: A system can be a single object or multiple objects you're focusing on - energy can transfer into it, out of it, or between different parts within it.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Here's the golden rule that'll save you marks in every energy question: the total energy in a closed system never changes. This means energy can't be created or destroyed, only moved around.
A closed system is one where neither matter nor energy can enter or leave - think of it like a sealed box. Even when dramatic changes happen inside, the total energy remains constant.
This principle helps you solve problems systematically. If a ball loses gravitational potential energy whilst falling, it must gain exactly the same amount of kinetic energy (ignoring air resistance). The numbers always balance out.
Exam Strategy: When stuck on energy questions, list what energy stores increase and decrease - they must equal each other!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Time for the maths bit - but don't worry, these equations are your friends once you practise them. Kinetic energy calculations pop up constantly, so memorise this formula: Ek = ½mv².
The equation tells you that doubling an object's speed actually quadruples its kinetic energy (because you're squaring the velocity). Mass matters too - heavier objects store more kinetic energy at the same speed.
For elastic potential energy, use Ee = ½ke². Here, 'k' represents the spring constant (how stiff the spring is), whilst 'e' shows how much you've stretched it. Stretch a spring twice as far, and you store four times more energy.
Gravitational potential energy uses the simpler formula Ep = mgh. This one's straightforward - more mass, greater height, or stronger gravity all mean more stored energy.
Calculator Tip: Watch out for that ½ in the kinetic and elastic energy equations - it's easy to forget under exam pressure!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Different materials need different amounts of energy to heat up - this property is called specific heat capacity. Water needs loads of energy to warm up, which is why the sea stays cool in summer and warm in winter.
Specific heat capacity measures how much energy you need to raise 1kg of a substance by 1°C. Materials with high specific heat capacities are excellent for storing thermal energy - that's why water works brilliantly in central heating systems.
The formula ΔE = mcΔθ connects energy transfer to temperature changes. 'ΔE' represents energy change, 'm' is mass, 'c' is specific heat capacity, and 'Δθ' shows temperature change.
This equation works both ways - heating up and cooling down. When substances cool, they release exactly the same amount of energy they absorbed when warming up.
Real-world Connection: Metal car seats heat up quickly in summer (low specific heat capacity), whilst the plastic dashboard stays cooler (higher specific heat capacity).
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
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.
You can download the app from Google Play Store and Apple App Store.
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
7
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Work and Energy explanation. Work done by a constant force. Work done by a variable force.
AP Physics 1Formulas, concepts of work, practice problem, and kinetic energy
AP Physics 1A presentation and discussion of the concepts of power, work, and energy.
AP Physics 1This describes a fundamental physics concept.
AP Physics 1Quotes from every main character
English LiteratureApp Store
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
Sociology