okay in this video we are going to be looking at the dangers and uses of electromagnetic waves [Music] make sure you watch the introduction to electromagnetic waves first so we are going to start with our smallest frequency waves and they are radio waves main use of radio waves is Communications long Wave radio waves could be transmitted and received halfway around the world that's because these long wavelengths allow the waves to be diffracted that basically just means that they can bend around Hills tunnels buildings and around the curved Earth that means a receiver can receive a wave even if the transmitter isn't directly in line with the receiver shortwave radio are not diffracted as well but they can still be received at large distances between the transmitter and the receiver use part of the Earth's atmosphere the ionosphere to reflect waves back down to earth an example of something that uses short wave radio is any Bluetooth device like my airpods I don't know if you've ever tried it but you can actually get quite surprising distances away from your phone without any Interruption to your Harry Styles bangers radio weaves that are used for TV or FM radio have quite short wavelengths so in order to get reception you need to be in sight of the transmitter that's why you'll often see those TV Aerials on the tops of chimneys okay now Bridging the Gap between radio and microwaves we have satellite Communications this is where a transmitter on Earth sends a wave out to a satellite in space the satellite in space then transmits a wave back down to earth to the receiver used for satellite TV satellite phones and internet and Military Communications those satellites must hold a lot of secrets so we either use high frequency radio waves or microwaves these waves can easily pass through the Earth's atmosphere without being diffracted reflected or refracted so they can reach the satellites easily another use of my microwaves is cooking speaking of which I've just made myself a delicious little treat in the microwave ah well you can see that but it is a microwave mug cake um Anya it is only half time in the morning I'm not sorry so microwaves are absorbed by water molecules in food and transfer the energy to thermal energy of the water molecules the water molecules heat up and then they transfer that energy to the other molecules in the food until it's cooked this means you can cook food really quickly like a cake in 40 seconds however there is some debate as to whether this property is also a bit dangerous because since cells in your body contain a lot of water the microwaves can cause those to heat up too juries fill out on how harmful this actually is next wave on our Spectrum infrared these can be used for thermal imaging you can see heat loss through different parts of say a house they can be used in security cameras a person gives off a lot of infrared radiation so an intruder can be detected cooking infrared causes things to get hotter heating elements on toasters use infrared radiation speaking of which I'm joking I don't need taste and the cake this morning and again for communications infrared signals are used in Optical fibers they can carry data across very long distances also an important one here TV remotes because who wants to get up off their sofa to change a TV channel however infrared radiation can lead to Burns because of its heating effect if it is absorbed by your skin luckily most infrared radiation is reflected okay next on our list visible light which we use to see but is also used in photography visible light is detected by digital cameras and converted into electrical signals to give you your photograph our next electromagnetic wave is UV UV can be used in security and it takes advantage of a property called fluorescence when UV is absorbed by fluorescent materials those materials then re-emit waves in the form of visible light waves so for example you can Mark a particular banknote with a fluorescent pen and then usually that marking would just be invisible to the naked eye but if you then shine a UV lamp onto your banknotes that fluorescent pen would absorb that UV and re-emit it as visible light so you'd see whatever invisible marking you had put onto your banknote in fact banknotes do have this and it makes it more difficult to forge your own banknotes UV can also be used to disinfect water because it has enough energy to damage and kill cells it can also kill bacteria in water but beware UV radiation can be absorbed by the skin it's ionizing radiation and it can cause cells in your skin to mutate 8 which could develop into skin cancer can also damage cells in your eyes which can eventually lead to blindness so make sure you've always got your sun cream that's a complete waste of sun cream because I'm literally filming this in February okay on to x-rays now we all know that x-rays can be used for medical imaging but how it actually works is your X-ray film begins clear and x-rays are really good at penetrating soft things like flesh but they are absorbed by more dense materials like bone your x-rays are sent through somebody's body and those that make it all the way through hit the clear screen and darken it those bits of your body that are bone absorb those X-rays and leave those parts of the X-ray clear so then you can build up an image sometimes x-rays are also used in airport security to detect some hidden objects well it's quicker than opening everybody's bag and having a good rummage through however x-rays are also ionizing and therefore can also cause cancer sometimes they actually kill cells entirely this causes radiation sickness even eventually death okay and finally gamma rays these can be used for sterilization like sterilization of medical equipment but they can also be used to detect and treat cancer to detect cancer somebody will ingest a source which emits gamma rays gamma rays emitted from the body can be detected by a detector and doctors can then use that information to determine if and where any tumors may be since ionizing radiation can kill cells it can also kill cancerous cells so gamma rays can be directed towards a tumor to kill it however just like x-rays gamma rays can lead to cancers if they are incident on normal cells radiation poisoning or death you may have noticed that the higher the energy of radiation or the smaller the frequency of radiation the more dangerous the electromagnetic waves are okay hope you found that helpful please do like and subscribe make sure you download the notes for all of those dangers and uses that thanks for watching