Subjects
Biology
Chemistry
AP Chemistry
English
AP English Literature
Science (ACT®)
Dec 10, 2025
78
22 pages
Josiah Reed @osiaheed_mylu3nkej4v
The electromagnetic spectrum is like a giant family of waves that surrounds us every day. From the radio... Show more
The electromagnetic spectrum (EMS) is the complete range of electromagnetic waves, from the longest to the shortest wavelengths. It includes radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays.
Scientists use these different types of waves to gather information about distant objects like stars and galaxies. Some of these waves can pass through Earth's atmosphere, while others are blocked before reaching us.
Each type of wave has its own unique properties that make it useful for different purposes. For example, radio waves help us communicate, while X-rays let doctors see inside our bodies.
Cool Fact Did you know that stars emit all types of electromagnetic waves? By studying these emissions, scientists can figure out what stars are made of without ever visiting them!
Waves are disturbances that travel through space and matter. Unlike throwing a ball, waves transfer energy without moving matter from place to place. Electromagnetic waves travel through electrical and magnetic fields.
The crest is the highest point of a wave, while the trough is the lowest point. The wavelength measures the distance between two consecutive crests (or troughs) - basically the length of one complete wave.
The amplitude is how tall a wave is, measured from the middle position to the crest. The frequency tells us how many wave crests pass a point in a certain amount of time, measured in Hertz (Hz).
Remember this Higher frequency waves have more energy than lower frequency waves. This is why gamma rays (highest frequency) can be dangerous, while radio waves (lowest frequency) are safe for everyday use.
Radio waves have the longest wavelengths and lowest frequencies in the electromagnetic spectrum. They're about the size of buildings! These waves easily penetrate Earth's atmosphere, which is why we can receive radio signals from space.
Radio waves are used for AM/FM radio stations and can even help astronomers study stars. They're produced by objects with very cool temperatures .
Microwaves have shorter wavelengths, about the size of humans. Your home Wi-Fi router, cell phone, and microwave oven all use these waves. Astronomers also detect microwaves from stars and other cosmic objects.
Try this Next time you're in a car, notice how radio stations change as you drive. This happens because radio waves can only travel so far before they get too weak to detect!
Infrared waves sit just below the visible light range . These waves are about the size of butterflies and are what makes you feel warmth from a fire or the sun.
Your TV remote uses infrared to send signals, and night vision goggles detect the infrared heat coming off people and animals. Astronomers use infrared telescopes to see through cosmic dust clouds.
Visible light is the only part of the spectrum we can see with our eyes. It includes all the colors of the rainbow . Stars like our sun produce massive amounts of visible light.
Think about it When you see a rainbow, you're actually seeing visible light split into its different wavelengths. Red has the longest wavelength, and violet has the shortest.
Ultraviolet (UV) light sits just beyond violet in the spectrum . These waves cause sunburns and make certain materials glow under "black lights" at haunted houses. The Earth's atmosphere blocks most UV rays from space.
X-rays have much shorter wavelengths, about the size of atoms. They can pass through soft tissues but are stopped by denser materials like bone, which is why doctors use them to see inside your body. Astronomers use X-ray telescopes to study extremely hot objects in space.
Gamma rays have the shortest wavelengths and highest energy in the spectrum. They're produced by the hottest objects in space (around 10 million degrees Celsius!) and by radioactive materials on Earth. They're used in cancer treatments and to sterilize medical equipment.
Mind-blowing fact If you could see gamma rays, the night sky would look completely different, with certain stars and galaxies appearing much brighter than they do in visible light!
Scientists can determine what stars are made of through spectroscopy - studying the unique patterns of light absorbed or emitted by different elements. Each element has a distinct "fingerprint" in the spectrum.
When astronomers spread out starlight into its component wavelengths, they see dark lines where certain elements absorbed specific wavelengths. By matching these patterns to known elements, they can identify what's in distant stars without ever visiting them.
To measure the distance to stars, astronomers use a method called parallax. They observe a star's position, wait six months until Earth has moved to the opposite side of its orbit (186 million miles away), and measure again. The apparent shift in the star's position helps calculate its distance.
Try it yourself Hold your thumb at arm's length and look at it with one eye closed, then switch eyes. Your thumb appears to "move" against the background. That's parallax - the same principle astronomers use to measure star distances!
Our AI companion is specifically built for the needs of students. Based on the millions of content pieces we have on the platform we can provide truly meaningful and relevant answers to students. But its not only about answers, the companion is even more about guiding students through their daily learning challenges, with personalised study plans, quizzes or content pieces in the chat and 100% personalisation based on the students skills and developments.
You can download the app in the Google Play Store and in the Apple App Store.
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
1
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
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
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
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
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 app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
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
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
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
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
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 app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
Paul T
iOS user
Josiah Reed
@osiaheed_mylu3nkej4v
The electromagnetic spectrum is like a giant family of waves that surrounds us every day. From the radio waves that bring music to your car to the X-rays at the doctor's office, these waves help us understand both our everyday... Show more
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
The electromagnetic spectrum (EMS) is the complete range of electromagnetic waves, from the longest to the shortest wavelengths. It includes radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays.
Scientists use these different types of waves to gather information about distant objects like stars and galaxies. Some of these waves can pass through Earth's atmosphere, while others are blocked before reaching us.
Each type of wave has its own unique properties that make it useful for different purposes. For example, radio waves help us communicate, while X-rays let doctors see inside our bodies.
Cool Fact: Did you know that stars emit all types of electromagnetic waves? By studying these emissions, scientists can figure out what stars are made of without ever visiting them!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Waves are disturbances that travel through space and matter. Unlike throwing a ball, waves transfer energy without moving matter from place to place. Electromagnetic waves travel through electrical and magnetic fields.
The crest is the highest point of a wave, while the trough is the lowest point. The wavelength measures the distance between two consecutive crests (or troughs) - basically the length of one complete wave.
The amplitude is how tall a wave is, measured from the middle position to the crest. The frequency tells us how many wave crests pass a point in a certain amount of time, measured in Hertz (Hz).
Remember this: Higher frequency waves have more energy than lower frequency waves. This is why gamma rays (highest frequency) can be dangerous, while radio waves (lowest frequency) are safe for everyday use.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Radio waves have the longest wavelengths and lowest frequencies in the electromagnetic spectrum. They're about the size of buildings! These waves easily penetrate Earth's atmosphere, which is why we can receive radio signals from space.
Radio waves are used for AM/FM radio stations and can even help astronomers study stars. They're produced by objects with very cool temperatures .
Microwaves have shorter wavelengths, about the size of humans. Your home Wi-Fi router, cell phone, and microwave oven all use these waves. Astronomers also detect microwaves from stars and other cosmic objects.
Try this: Next time you're in a car, notice how radio stations change as you drive. This happens because radio waves can only travel so far before they get too weak to detect!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Infrared waves sit just below the visible light range . These waves are about the size of butterflies and are what makes you feel warmth from a fire or the sun.
Your TV remote uses infrared to send signals, and night vision goggles detect the infrared heat coming off people and animals. Astronomers use infrared telescopes to see through cosmic dust clouds.
Visible light is the only part of the spectrum we can see with our eyes. It includes all the colors of the rainbow . Stars like our sun produce massive amounts of visible light.
Think about it: When you see a rainbow, you're actually seeing visible light split into its different wavelengths. Red has the longest wavelength, and violet has the shortest.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Ultraviolet (UV) light sits just beyond violet in the spectrum . These waves cause sunburns and make certain materials glow under "black lights" at haunted houses. The Earth's atmosphere blocks most UV rays from space.
X-rays have much shorter wavelengths, about the size of atoms. They can pass through soft tissues but are stopped by denser materials like bone, which is why doctors use them to see inside your body. Astronomers use X-ray telescopes to study extremely hot objects in space.
Gamma rays have the shortest wavelengths and highest energy in the spectrum. They're produced by the hottest objects in space (around 10 million degrees Celsius!) and by radioactive materials on Earth. They're used in cancer treatments and to sterilize medical equipment.
Mind-blowing fact: If you could see gamma rays, the night sky would look completely different, with certain stars and galaxies appearing much brighter than they do in visible light!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Scientists can determine what stars are made of through spectroscopy - studying the unique patterns of light absorbed or emitted by different elements. Each element has a distinct "fingerprint" in the spectrum.
When astronomers spread out starlight into its component wavelengths, they see dark lines where certain elements absorbed specific wavelengths. By matching these patterns to known elements, they can identify what's in distant stars without ever visiting them.
To measure the distance to stars, astronomers use a method called parallax. They observe a star's position, wait six months until Earth has moved to the opposite side of its orbit (186 million miles away), and measure again. The apparent shift in the star's position helps calculate its distance.
Try it yourself: Hold your thumb at arm's length and look at it with one eye closed, then switch eyes. Your thumb appears to "move" against the background. That's parallax - the same principle astronomers use to measure star distances!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
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 specifically built for the needs of students. Based on the millions of content pieces we have on the platform we can provide truly meaningful and relevant answers to students. But its not only about answers, the companion is even more about guiding students through their daily learning challenges, with personalised study plans, quizzes or content pieces in the chat and 100% personalisation based on the students skills and developments.
You can download the app in the Google Play Store and in the Apple App Store.
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
1
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
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
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
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
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 app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
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
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
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
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
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 app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
Paul T
iOS user
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