Maths
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Responding to change (a2 only)
Infection and response
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Organisms respond to changes in their internal and external environments (a-level only)
Biological molecules
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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
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Biology
6 Dec 2025
139
2 pages
gift @esilia
Ever wondered how scientists can see tiny cells and discover what's inside them? Microscopes are your gateway to... Show more
Microscopes are basically powerful magnifying glasses that let you see things way too small for your naked eye. Light microscopes are brilliant for studying cells and can show you cool structures like chloroplasts and the nucleus inside cells.
Electron microscopes are the supercharged versions that came later. They can magnify specimens much more than light microscopes and reveal incredible detail. These high-tech tools have revolutionised our understanding of what actually happens inside cells.
When preparing a specimen for viewing, you'll slice it thin, place it on a slide with a drop of water, and might add some stain to make features pop out. The trick is lowering that cover slip carefully with tweezers to avoid air bubbles - they're annoying and ruin your view!
To actually view your specimen, start with the lowest magnification objective lens and use the coarse adjustment knob first, then fine-tune with the fine adjustment. Always look through the eyepiece whilst moving the stage down until everything comes into focus.
Top Tip When drawing what you see, use a sharp pencil for smooth lines, label clearly without crossing lines, and never colour or shade your scientific drawings!
Working out total magnification is straightforward once you know the formula eyepiece lens magnification × objective lens magnification. If your eyepiece is ×10 and objective lens is ×40, you get ×400 total magnification.
Sometimes you'll need to calculate magnification when you don't know what lenses were used. The key formula is magnification = image size ÷ real size. Just make sure both measurements use the same units!
The formula triangle is your best friend for these calculations. Cover what you want to find, and what's left showing gives you the formula. Need real size? Cover it up and you'll see image size ÷ magnification.
Unit conversions are crucial in microscopy work. Remember that millimetres (mm) convert to micrometres (µm) by multiplying by 1000, and µm converts to nanometres (nm) the same way. Going backwards, you divide by 1000 each time.
Quick Trick If you can't measure something precisely, estimate by comparing it to something you do know the size of - like saying a nucleus looks half the width of a 10 µm cell, so it's roughly 5 µm!
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.
2
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Explore the various types of microscopes including Optical, Transmission Electron Microscopes (TEMs), and Scanning Electron Microscopes (SEMs). This summary covers key concepts such as magnification, resolution, and the advantages and disadvantages of each microscope type. Ideal for A-level biology students studying cell structure and microscopy techniques.
BiologyMaster the essential steps for using a microscope effectively in Year 7 science. This guide covers key components such as the ocular lens, objective lenses, and stage controls, along with detailed instructions for focusing and magnification adjustments. Ideal for students preparing for exams or practical assessments.
BiologyExplore the intricate structures and functions of eukaryotic cells, including organelles like the nucleus, mitochondria, and chloroplasts. This summary covers key concepts in cellular biology, microscopy techniques, and the differences between prokaryotic and eukaryotic cells. Ideal for students studying cell biology and related fields.
BiologyExplore the essentials of microscopy, including types of microscopes, magnification, and resolution. This summary covers the history of light and electron microscopes, detailing their functions and applications in scientific observation. Ideal for students seeking a clear understanding of microscopy concepts.
BiologyExplore essential microscopy techniques, including slide preparation, staining methods, and the development of cell theory. This summary covers key historical milestones, types of microscopes, and practical applications in biology, making it ideal for A Level Biology students. Understand how to differentiate between cell types and the significance of staining in microscopy.
BiologyExplore the differences between light and electron microscopes, focusing on magnification and resolution. Learn how to calculate magnification using various units, including micrometers and nanometers. This summary provides essential insights for students studying microscopy.
BiologyQuotes 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
gift
@esilia
Ever wondered how scientists can see tiny cells and discover what's inside them? Microscopes are your gateway to exploring the invisible world around you. Understanding how to use microscopes and calculate magnifications is essential for biology studies and will help... Show more
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Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Microscopes are basically powerful magnifying glasses that let you see things way too small for your naked eye. Light microscopes are brilliant for studying cells and can show you cool structures like chloroplasts and the nucleus inside cells.
Electron microscopes are the supercharged versions that came later. They can magnify specimens much more than light microscopes and reveal incredible detail. These high-tech tools have revolutionised our understanding of what actually happens inside cells.
When preparing a specimen for viewing, you'll slice it thin, place it on a slide with a drop of water, and might add some stain to make features pop out. The trick is lowering that cover slip carefully with tweezers to avoid air bubbles - they're annoying and ruin your view!
To actually view your specimen, start with the lowest magnification objective lens and use the coarse adjustment knob first, then fine-tune with the fine adjustment. Always look through the eyepiece whilst moving the stage down until everything comes into focus.
Top Tip: When drawing what you see, use a sharp pencil for smooth lines, label clearly without crossing lines, and never colour or shade your scientific drawings!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Working out total magnification is straightforward once you know the formula: eyepiece lens magnification × objective lens magnification. If your eyepiece is ×10 and objective lens is ×40, you get ×400 total magnification.
Sometimes you'll need to calculate magnification when you don't know what lenses were used. The key formula is: magnification = image size ÷ real size. Just make sure both measurements use the same units!
The formula triangle is your best friend for these calculations. Cover what you want to find, and what's left showing gives you the formula. Need real size? Cover it up and you'll see image size ÷ magnification.
Unit conversions are crucial in microscopy work. Remember that millimetres (mm) convert to micrometres (µm) by multiplying by 1000, and µm converts to nanometres (nm) the same way. Going backwards, you divide by 1000 each time.
Quick Trick: If you can't measure something precisely, estimate by comparing it to something you do know the size of - like saying a nucleus looks half the width of a 10 µm cell, so it's roughly 5 µm!
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.
2
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Explore the various types of microscopes including Optical, Transmission Electron Microscopes (TEMs), and Scanning Electron Microscopes (SEMs). This summary covers key concepts such as magnification, resolution, and the advantages and disadvantages of each microscope type. Ideal for A-level biology students studying cell structure and microscopy techniques.
BiologyMaster the essential steps for using a microscope effectively in Year 7 science. This guide covers key components such as the ocular lens, objective lenses, and stage controls, along with detailed instructions for focusing and magnification adjustments. Ideal for students preparing for exams or practical assessments.
BiologyExplore the intricate structures and functions of eukaryotic cells, including organelles like the nucleus, mitochondria, and chloroplasts. This summary covers key concepts in cellular biology, microscopy techniques, and the differences between prokaryotic and eukaryotic cells. Ideal for students studying cell biology and related fields.
BiologyExplore the essentials of microscopy, including types of microscopes, magnification, and resolution. This summary covers the history of light and electron microscopes, detailing their functions and applications in scientific observation. Ideal for students seeking a clear understanding of microscopy concepts.
BiologyExplore essential microscopy techniques, including slide preparation, staining methods, and the development of cell theory. This summary covers key historical milestones, types of microscopes, and practical applications in biology, making it ideal for A Level Biology students. Understand how to differentiate between cell types and the significance of staining in microscopy.
BiologyExplore the differences between light and electron microscopes, focusing on magnification and resolution. Learn how to calculate magnification using various units, including micrometers and nanometers. This summary provides essential insights for students studying microscopy.
BiologyQuotes 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