Subjects
Maths
Chemistry
Biology
English Language
History
Responding to change (a2 only)
Infection and response
Homeostasis and response
Energy transfers (a2 only)
Cell biology
Organisms respond to changes in their internal and external environments (a-level only)
Biological molecules
Organisation
Substance exchange
Bioenergetics
Genetic information & variation
Inheritance, variation and evolution
Genetics & ecosystems (a2 only)
Ecology
Cells
Show all topics
Britain & the wider world: 1745 -1901
1l the quest for political stability: germany, 1871-1991
The cold war
Inter-war germany
Medieval period: 1066 -1509
2d religious conflict and the church in england, c1529-c1570
2o democracy and nazism: germany, 1918-1945
1f industrialisation and the people: britain, c1783-1885
1c the tudors: england, 1485-1603
2m wars and welfare: britain in transition, 1906-1957
World war two & the holocaust
2n revolution and dictatorship: russia, 1917-1953
2s the making of modern britain, 1951-2007
World war one
Britain: 1509 -1745
Show all topics
Physics
11 Dec 2025
187
6 pages
Scarlett Edwardes @scarlett_1917
Physics is all about how energy behaves in our world. Energy never disappears but constantly moves between different... Show more
Energy is one of the most fundamental concepts in physics that you'll use throughout your studies. The most important thing to remember is that energy is never created or destroyed—it simply changes form.
Energy exists in various stores including thermal (internal), kinetic, gravitational potential, elastic potential, chemical, magnetic, nuclear, and electrostatic. When energy moves from one store to another, we call this a transfer.
Energy transfers happen in four main ways mechanically (through forces doing work), electronically (by moving charges), heating (work done by heat), and radiation (work done by light or sound).
Remember this! When energy moves from one store to another, physicists call this "work done." This concept will appear repeatedly in your exams.
When you lift an object upwards, you're transferring energy into its gravitational potential energy (GPE) store. The higher you lift it, the more energy is stored.
This happens because the object exists in Earth's gravitational field, and energy is needed to work against this force. The amount of GPE depends on three factors the object's mass, its height, and the strength of the gravitational field.
We calculate changes in GPE using the formula Ep = mgh where m is mass in kg, g is gravitational field strength in N/kg, and h is height in meters.
Quick fact The gravitational field strength on Earth is approximately 10 N/kg. This value makes calculations in your exams much easier!
Kinetic energy is the energy an object has due to its motion. Energy transfers into the kinetic store when an object speeds up and transfers away when it slows down.
The amount of energy in this store depends on both the object's mass and its speed, calculated using Ek = ½mv² where m is mass in kg and v is speed in m/s. Notice that doubling the speed quadruples the kinetic energy!
When an object falls, energy transfers between gravitational potential energy and kinetic energy stores. With no air resistance, the energy lost from the GPE store equals the energy gained in the kinetic store—this is conservation of energy in action.
Important In real-world situations, air resistance causes some energy to be transferred to the thermal store of the surroundings instead of just to kinetic energy. This is why falling objects reach a terminal velocity.
Elastic potential energy is stored when you stretch or compress objects like springs. Think about pulling back a catapult or stretching a rubber band—you're storing energy!
As long as you don't stretch beyond the limit of proportionality (where the object's behavior changes), elastic potential energy can be calculated using Ee = ½ke² where k is the spring constant in N/m and e is extension in m.
The spring constant tells us how stiff a spring is—a higher value means a stiffer spring that's harder to stretch but stores more energy for the same extension.
Key concept The limit of proportionality marks where Hooke's Law stops working. Before this point, extension is directly proportional to the force applied. This relationship appears regularly in exam questions!
Thermal energy (also called internal energy) is the total kinetic energy of all particles in an object. It's what we're really talking about when we discuss temperature—the more energetic the particles, the higher the temperature.
Different materials require different amounts of energy to heat up. Specific heat capacity measures how much energy (in joules) is needed to raise the temperature of 1kg of a substance by 1°C.
We calculate changes in thermal energy using E = mc∆θ where E is energy in joules, m is mass in kg, c is specific heat capacity in J/kg°C, and ∆θ is the temperature change in °C.
Practical application Materials with high specific heat capacity (like water) are excellent for storing thermal energy, which is why they're used in heating systems. This concept helps explain why coastal areas have milder climates than inland regions.
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.
6
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Physics
Physicshere is a study guide to help you !
PhysicsThis includes different formulas involved in physics subject.
PhysicsZoology Notes
PhysicsExplore the key concepts of energy conservation and dissipation, including power, efficiency, and the relationship between force and extension in elastic materials. This summary covers essential terms and principles relevant to energy transfers in electrical appliances and the limitations of proportionality in force-extension graphs.
PhysicsExplore key concepts in physics related to energy, power, and electricity. This resource covers topics such as energy transfer, Ohm's Law, radioactivity, and thermal energy, providing a comprehensive overview for GCSE Triple Science revision. Ideal for students preparing for exams, this summary includes essential equations and principles to enhance understanding.
PhysicsApp 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
Scarlett Edwardes
@scarlett_1917
Physics is all about how energy behaves in our world. Energy never disappears but constantly moves between different stores through various transfer methods. Understanding these energy stores and their mathematical relationships is key to mastering many physics concepts.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Energy is one of the most fundamental concepts in physics that you'll use throughout your studies. The most important thing to remember is that energy is never created or destroyed—it simply changes form.
Energy exists in various stores including thermal (internal), kinetic, gravitational potential, elastic potential, chemical, magnetic, nuclear, and electrostatic. When energy moves from one store to another, we call this a transfer.
Energy transfers happen in four main ways: mechanically (through forces doing work), electronically (by moving charges), heating (work done by heat), and radiation (work done by light or sound).
Remember this! When energy moves from one store to another, physicists call this "work done." This concept will appear repeatedly in your exams.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
When you lift an object upwards, you're transferring energy into its gravitational potential energy (GPE) store. The higher you lift it, the more energy is stored.
This happens because the object exists in Earth's gravitational field, and energy is needed to work against this force. The amount of GPE depends on three factors: the object's mass, its height, and the strength of the gravitational field.
We calculate changes in GPE using the formula: Ep = mgh where m is mass in kg, g is gravitational field strength in N/kg, and h is height in meters.
Quick fact: The gravitational field strength on Earth is approximately 10 N/kg. This value makes calculations in your exams much easier!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Kinetic energy is the energy an object has due to its motion. Energy transfers into the kinetic store when an object speeds up and transfers away when it slows down.
The amount of energy in this store depends on both the object's mass and its speed, calculated using: Ek = ½mv² where m is mass in kg and v is speed in m/s. Notice that doubling the speed quadruples the kinetic energy!
When an object falls, energy transfers between gravitational potential energy and kinetic energy stores. With no air resistance, the energy lost from the GPE store equals the energy gained in the kinetic store—this is conservation of energy in action.
Important: In real-world situations, air resistance causes some energy to be transferred to the thermal store of the surroundings instead of just to kinetic energy. This is why falling objects reach a terminal velocity.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Elastic potential energy is stored when you stretch or compress objects like springs. Think about pulling back a catapult or stretching a rubber band—you're storing energy!
As long as you don't stretch beyond the limit of proportionality (where the object's behavior changes), elastic potential energy can be calculated using: Ee = ½ke² where k is the spring constant in N/m and e is extension in m.
The spring constant tells us how stiff a spring is—a higher value means a stiffer spring that's harder to stretch but stores more energy for the same extension.
Key concept: The limit of proportionality marks where Hooke's Law stops working. Before this point, extension is directly proportional to the force applied. This relationship appears regularly in exam questions!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Thermal energy (also called internal energy) is the total kinetic energy of all particles in an object. It's what we're really talking about when we discuss temperature—the more energetic the particles, the higher the temperature.
Different materials require different amounts of energy to heat up. Specific heat capacity measures how much energy (in joules) is needed to raise the temperature of 1kg of a substance by 1°C.
We calculate changes in thermal energy using: E = mc∆θ where E is energy in joules, m is mass in kg, c is specific heat capacity in J/kg°C, and ∆θ is the temperature change in °C.
Practical application: Materials with high specific heat capacity (like water) are excellent for storing thermal energy, which is why they're used in heating systems. This concept helps explain why coastal areas have milder climates than inland regions.
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.
6
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Physics
Physicshere is a study guide to help you !
PhysicsThis includes different formulas involved in physics subject.
PhysicsZoology Notes
PhysicsExplore the key concepts of energy conservation and dissipation, including power, efficiency, and the relationship between force and extension in elastic materials. This summary covers essential terms and principles relevant to energy transfers in electrical appliances and the limitations of proportionality in force-extension graphs.
PhysicsExplore key concepts in physics related to energy, power, and electricity. This resource covers topics such as energy transfer, Ohm's Law, radioactivity, and thermal energy, providing a comprehensive overview for GCSE Triple Science revision. Ideal for students preparing for exams, this summary includes essential equations and principles to enhance understanding.
PhysicsApp 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