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
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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
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60
•
6 Dec 2025
•
Amy Wan
@amymel0n
Electric circuits might seem complex, but they're actually quite straightforward... Show more
Understanding circuit symbols is like learning the alphabet of electronics - once you know them, you can read any circuit diagram. The most essential components include cells (which push electrons around circuits) and batteries (multiple cells working together).
Resistors are crucial for controlling current flow. Fixed resistors limit current by a set amount, while variable resistors let you adjust the current - think of a dimmer switch for lights. Some resistors even respond to their environment: light dependent resistors (LDRs) change resistance based on brightness, and thermistors change with temperature.
Safety components like fuses protect circuits by melting if too much current flows through. Meanwhile, measuring devices like ammeters (for current) and voltmeters (for potential difference) help you understand what's happening in your circuit.
Quick Tip: Remember that LEDs and regular bulbs both emit light, but LEDs are much more efficient and last longer!
Electric current flows like a river of electrons carrying energy around a circuit, measured in amperes (A). The key rule to remember: current is never "used up" - it's the same all the way around a series circuit.
In a series circuit, there's only one path for current to take. This means if one component breaks, the whole circuit stops working (like old Christmas lights). The current has the same value everywhere in the loop.
Parallel circuits work differently - they have multiple branches for current to flow through. The total current splits up between the branches, then rejoins before returning to the cell. If you measure 0.3A leaving the cell, and one branch carries 0.1A while another carries 0.2A, they add up perfectly .
Remember: In series circuits, current stays constant. In parallel circuits, current divides between branches but the total always adds up!
Potential difference (or voltage) is the electrical "push" that drives current through components - think of it as electrical pressure. In series circuits, this voltage gets shared between all components, like splitting a pizza between friends.
When you connect identical bulbs in series, each gets an equal share of the total potential difference. This is why bulbs in series are dimmer than when connected alone - they're each getting less voltage to work with.
Parallel circuits behave completely differently. Here, each branch gets the full voltage from the cell, which is why bulbs in parallel shine brighter than those in series. The potential difference across each parallel branch equals the cell's total voltage.
Key Point: Series circuits share voltage between components, while parallel circuits give full voltage to each branch - that's why your house uses parallel wiring!
Resistance determines how much a component opposes the flow of current, measured in ohms (Ω). Think of it like a narrow pipe restricting water flow - higher resistance means less current can pass through.
The relationship between voltage, current, and resistance follows Ohm's Law: Resistance = Voltage ÷ Current . This equation is your best friend for circuit calculations and will appear constantly in your exams.
For fixed resistors, the resistance stays constant as long as temperature doesn't change. This creates a straight line on a current-voltage graph, showing that current increases proportionally with voltage.
Exam Tip: Master the resistance equation R = V/I - you'll use it in almost every circuit calculation question!
Filament lamps break the rules you've just learned about resistors, and that's what makes them interesting! Unlike fixed resistors, their resistance changes as they heat up.
When you increase the potential difference across a filament bulb, it gets hotter and brighter. However, this heat causes the resistance to increase, which means less current flows than you'd expect from Ohm's Law.
The reason is simple: as the filament heats up, electrons collide more frequently with the hot metal atoms. These extra collisions make it harder for current to flow, effectively increasing the resistance. This is why a filament lamp's current-voltage graph curves rather than forming a straight line.
Physics Insight: This heating effect is actually useful - it's how the bulb produces light, converting electrical energy into heat and light energy!
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.
This is the aqa exam board for triple highwe
ChemistryApp 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
Amy Wan
@amymel0n
Electric circuits might seem complex, but they're actually quite straightforward once you understand the basic components and how current behaves. Think of electricity like water flowing through pipes - it needs a complete path to flow and different components affect... Show more
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Improve your grades
Join milions of students
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Understanding circuit symbols is like learning the alphabet of electronics - once you know them, you can read any circuit diagram. The most essential components include cells (which push electrons around circuits) and batteries (multiple cells working together).
Resistors are crucial for controlling current flow. Fixed resistors limit current by a set amount, while variable resistors let you adjust the current - think of a dimmer switch for lights. Some resistors even respond to their environment: light dependent resistors (LDRs) change resistance based on brightness, and thermistors change with temperature.
Safety components like fuses protect circuits by melting if too much current flows through. Meanwhile, measuring devices like ammeters (for current) and voltmeters (for potential difference) help you understand what's happening in your circuit.
Quick Tip: Remember that LEDs and regular bulbs both emit light, but LEDs are much more efficient and last longer!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Electric current flows like a river of electrons carrying energy around a circuit, measured in amperes (A). The key rule to remember: current is never "used up" - it's the same all the way around a series circuit.
In a series circuit, there's only one path for current to take. This means if one component breaks, the whole circuit stops working (like old Christmas lights). The current has the same value everywhere in the loop.
Parallel circuits work differently - they have multiple branches for current to flow through. The total current splits up between the branches, then rejoins before returning to the cell. If you measure 0.3A leaving the cell, and one branch carries 0.1A while another carries 0.2A, they add up perfectly .
Remember: In series circuits, current stays constant. In parallel circuits, current divides between branches but the total always adds up!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Potential difference (or voltage) is the electrical "push" that drives current through components - think of it as electrical pressure. In series circuits, this voltage gets shared between all components, like splitting a pizza between friends.
When you connect identical bulbs in series, each gets an equal share of the total potential difference. This is why bulbs in series are dimmer than when connected alone - they're each getting less voltage to work with.
Parallel circuits behave completely differently. Here, each branch gets the full voltage from the cell, which is why bulbs in parallel shine brighter than those in series. The potential difference across each parallel branch equals the cell's total voltage.
Key Point: Series circuits share voltage between components, while parallel circuits give full voltage to each branch - that's why your house uses parallel wiring!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Resistance determines how much a component opposes the flow of current, measured in ohms (Ω). Think of it like a narrow pipe restricting water flow - higher resistance means less current can pass through.
The relationship between voltage, current, and resistance follows Ohm's Law: Resistance = Voltage ÷ Current . This equation is your best friend for circuit calculations and will appear constantly in your exams.
For fixed resistors, the resistance stays constant as long as temperature doesn't change. This creates a straight line on a current-voltage graph, showing that current increases proportionally with voltage.
Exam Tip: Master the resistance equation R = V/I - you'll use it in almost every circuit calculation question!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Filament lamps break the rules you've just learned about resistors, and that's what makes them interesting! Unlike fixed resistors, their resistance changes as they heat up.
When you increase the potential difference across a filament bulb, it gets hotter and brighter. However, this heat causes the resistance to increase, which means less current flows than you'd expect from Ohm's Law.
The reason is simple: as the filament heats up, electrons collide more frequently with the hot metal atoms. These extra collisions make it harder for current to flow, effectively increasing the resistance. This is why a filament lamp's current-voltage graph curves rather than forming a straight line.
Physics Insight: This heating effect is actually useful - it's how the bulb produces light, converting electrical energy into heat and light energy!
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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Explore 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.
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 the fundamental mechanisms of heat transfer: conduction, convection, and radiation. This summary covers how energy is transferred through different mediums, the role of particle movement, and the properties of thermal conductors. Ideal for students studying physics concepts related to thermal energy.
PhysicsExplore the types of energy resources, including renewable and non-renewable sources, their environmental impacts, and applications in transport and heating. This summary covers key concepts such as fossil fuels, biofuels, and sustainable energy solutions, providing a comprehensive understanding for students studying energy resources.
Physicsmomentum, impulse, conservation of momentum
PhysicsThis is the aqa exam board for triple highwe
ChemistryApp 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