Energy is everywhere around us - from the electricity powering... Show more
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Subjects
Classic Dramatic Literature
Modern Lyric Poetry
Influential English-Language Authors
Classic and Contemporary Novels
Literary Character Analysis
Romantic and Love Poetry
Reading Analysis and Interpretation
Evidence Analysis and Integration
Author's Stylistic Elements
Figurative Language and Rhetoric
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Human Organ Systems
Cellular Organization and Development
Biomolecular Structure and Organization
Enzyme Structure and Regulation
Cellular Organization Types
Biological Homeostatic Processes
Cellular Membrane Structure
Autotrophic Energy Processes
Environmental Sustainability and Impact
Neural Communication Systems
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Social Sciences Research & Practice
Social Structure and Mobility
Classic Social Influence Experiments
Social Systems Theories
Family and Relationship Dynamics
Memory Systems and Processes
Neural Bases of Behavior
Social Influence and Attraction
Psychotherapeutic Approaches
Human Agency and Responsibility
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Chemical Sciences and Applications
Chemical Bond Types and Properties
Organic Functional Groups
Atomic Structure and Composition
Chromatographic Separation Principles
Chemical Compound Classifications
Electrochemical Cell Systems
Periodic Table Organization
Chemical Reaction Kinetics
Chemical Equation Conservation
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Nazi Germany and Holocaust 1933-1945
World Wars and Peace Treaties
European Monarchs and Statesmen
Cold War Global Tensions
Medieval Institutions and Systems
European Renaissance and Enlightenment
Modern Global Environmental-Health Challenges
Modern Military Conflicts
Medieval Migration and Invasions
World Wars Era and Impact
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93
•
23 Dec 2025
•
lola
@lola_3dks5
Energy is everywhere around us - from the electricity powering... Show more




Energy stores are like different ways energy can be "kept" - think kinetic energy in moving objects, gravitational potential energy in anything up high, and chemical energy in food or fuel. When you kick a football, chemical energy from your muscles transfers to kinetic energy in the ball.
Renewable energy sources like wind, solar, and hydro-electricity won't run out, but they can be unreliable and expensive to set up initially. Wind turbines only work when it's windy, and solar panels need sunlight. However, they produce no pollution once they're running.
Non-renewable sources like coal, oil, and gas provide about 80% of our energy because they're reliable and cost-effective. The problem? They're slowly running out and add to greenhouse gases that cause global warming. Nuclear energy is incredibly powerful but can be dangerous to handle and dispose of.
Quick tip: Remember that energy can never be created or destroyed - it just transfers from one store to another. This is the conservation of energy.
The specific heat capacity tells you how much energy you need to heat 1kg of a substance by 1°C. Materials with high specific heat capacity (like water) take loads of energy to heat up, which is why the sea stays cool in summer.

Your home runs on 230V mains electricity at 50Hz frequency, delivered through the national grid at voltages up to 400,000V. The live wire (brown) carries the current, neutral (blue) completes the circuit, and earth keeps you safe.
Static electricity happens when electrons build up on objects through friction - like when you rub a balloon on your hair. Remember: like charges repel, opposite charges attract. Only electrons move, never protons.
Circuit components behave differently depending on conditions. LDRs (light dependent resistors) have high resistance in darkness and low resistance in bright light. Thermistors are temperature-dependent - as they heat up, their resistance drops.
In series circuits, current flows through each component one after another - if one breaks, they all stop working. Parallel circuits split the current between branches, so if one component fails, the others keep working.
Remember: In series circuits, current is the same everywhere but voltage is shared. In parallel circuits, voltage is the same across each branch but current is shared.
Ohmic conductors have constant resistance when temperature stays the same. Filament bulbs aren't ohmic because their resistance increases as they heat up.

Density equals mass divided by volume , measured in kg/m³. Solids are usually densest because particles are packed tightly together, whilst gases have very low density because particles are spread far apart.
The particle model explains that all matter is made of constantly moving particles. In gases, particles move faster and collide more as temperature increases, creating pressure. Internal energy is the total kinetic and potential energy of all particles in a substance.
Atomic models have evolved from Dalton's solid spheres to our current understanding. The nucleus contains protons and neutrons, with electrons orbiting in energy levels. Isotopes have the same number of protons but different numbers of neutrons.
Radioactive decay is completely random and gives off three types of radiation. Alpha particles (helium nuclei) are stopped by paper and highly ionising. Beta particles penetrate aluminium and are moderately ionising. Gamma rays are electromagnetic waves that penetrate concrete and are weakly ionising.
Key fact: Half-life is the time taken for half the radioactive nuclei in a sample to decay - this helps us predict how long radioactive materials remain dangerous.
Background radiation comes from space, rocks, and human activities. We measure radiation using Geiger-Muller tubes. Nuclear fission splits large nuclei to release energy (used in power stations), whilst fusion combines small nuclei (happens in stars).
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.
App 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
lola
@lola_3dks5
Energy is everywhere around us - from the electricity powering your phone to the petrol in cars. Understanding how energy works, along with the basics of electricity and atomic structure, helps explain everything from renewable power sources to how your... Show more

Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Energy stores are like different ways energy can be "kept" - think kinetic energy in moving objects, gravitational potential energy in anything up high, and chemical energy in food or fuel. When you kick a football, chemical energy from your muscles transfers to kinetic energy in the ball.
Renewable energy sources like wind, solar, and hydro-electricity won't run out, but they can be unreliable and expensive to set up initially. Wind turbines only work when it's windy, and solar panels need sunlight. However, they produce no pollution once they're running.
Non-renewable sources like coal, oil, and gas provide about 80% of our energy because they're reliable and cost-effective. The problem? They're slowly running out and add to greenhouse gases that cause global warming. Nuclear energy is incredibly powerful but can be dangerous to handle and dispose of.
Quick tip: Remember that energy can never be created or destroyed - it just transfers from one store to another. This is the conservation of energy.
The specific heat capacity tells you how much energy you need to heat 1kg of a substance by 1°C. Materials with high specific heat capacity (like water) take loads of energy to heat up, which is why the sea stays cool in summer.

Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Your home runs on 230V mains electricity at 50Hz frequency, delivered through the national grid at voltages up to 400,000V. The live wire (brown) carries the current, neutral (blue) completes the circuit, and earth keeps you safe.
Static electricity happens when electrons build up on objects through friction - like when you rub a balloon on your hair. Remember: like charges repel, opposite charges attract. Only electrons move, never protons.
Circuit components behave differently depending on conditions. LDRs (light dependent resistors) have high resistance in darkness and low resistance in bright light. Thermistors are temperature-dependent - as they heat up, their resistance drops.
In series circuits, current flows through each component one after another - if one breaks, they all stop working. Parallel circuits split the current between branches, so if one component fails, the others keep working.
Remember: In series circuits, current is the same everywhere but voltage is shared. In parallel circuits, voltage is the same across each branch but current is shared.
Ohmic conductors have constant resistance when temperature stays the same. Filament bulbs aren't ohmic because their resistance increases as they heat up.

Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Density equals mass divided by volume , measured in kg/m³. Solids are usually densest because particles are packed tightly together, whilst gases have very low density because particles are spread far apart.
The particle model explains that all matter is made of constantly moving particles. In gases, particles move faster and collide more as temperature increases, creating pressure. Internal energy is the total kinetic and potential energy of all particles in a substance.
Atomic models have evolved from Dalton's solid spheres to our current understanding. The nucleus contains protons and neutrons, with electrons orbiting in energy levels. Isotopes have the same number of protons but different numbers of neutrons.
Radioactive decay is completely random and gives off three types of radiation. Alpha particles (helium nuclei) are stopped by paper and highly ionising. Beta particles penetrate aluminium and are moderately ionising. Gamma rays are electromagnetic waves that penetrate concrete and are weakly ionising.
Key fact: Half-life is the time taken for half the radioactive nuclei in a sample to decay - this helps us predict how long radioactive materials remain dangerous.
Background radiation comes from space, rocks, and human activities. We measure radiation using Geiger-Muller tubes. Nuclear fission splits large nuclei to release energy (used in power stations), whilst fusion combines small nuclei (happens in stars).
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.
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Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
App 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