Hello and welcome to this lesson on ionising electromagnetic radiation.

My name's Mr. Noris, and this lesson is from the unit called electromagnetic waves.

So, this lesson picks up our study of electromagnetic waves and we need to look at some of them in more detail, which are considered the most harmful.

And the reason they're most harmful is because they're ionising.

Now, that's a word you've probably come across in your science studies, but perhaps more related to chemistry and ions and atoms becoming ions.

So, some kinds of electromagnetic radiation have the power to ionise atoms, to make atoms become ions.

So we need to go over that this lesson and then look at how these kinds of ionising electromagnetic wave or electromagnetic radiation can do that and the potential harms and uses it can have.

The outcome of this lesson is by the end of the lesson, hopefully you'll be able to explain the properties, uses, and dangers of ionising electromagnetic radiations.

Some key words that will come up this lesson are energy transfer, ionisation, ultraviolet, X-ray, and gamma ray.

Each word will be explained as it comes up in the lesson.

If you would like to recap the meaning of each keyword for this lesson, you could pause the video now to have a check through these definitions.

The lesson has two sections.

In the first section, we'll look at energy transfer and ionisation by electromagnetic radiation.

And in the second section, we'll look in detail at the kinds of electromagnetic radiation that are ionising, ultraviolet, X-rays, and gamma rays.

Let's get started.

So, we know that different frequencies of electromagnetic wave interact differently with different materials.

And on the screen now is the diagram showing the full spectrum of frequencies of electromagnetic wave going from the lowest frequencies that are possible for electromagnetic wave, which are called radio waves.

Then increasing in frequency to microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays.

So that's the full spectrum of possible frequencies of electromagnetic wave.

You can see the bottom scale shows the wavelengths of each frequency of electromagnetic wave.

Now, electromagnetic waves, whatever their frequency, transfer energy when they're emitted from objects.

For example, when objects cool down by emitting infrared radiation, then they're transferring energy into the surroundings or to an object which then absorbs that infrared radiation.

When lamps emit visible radiation, they're giving out light that's electromagnetic radiation that transfers energy to whatever might absorb that light.

Maybe a solar panel.

And radioactive atoms emit gamma rays, which then transfer energy elsewhere.

So there are three examples of electromagnetic waves of different frequencies, transferring energy when they're emitted.

And energy is also transferred when electromagnetic radiation is absorbed.

For example, we mentioned when a surface is then heated by infrared radiation, radio waves can cause an electrical current in a conductor.

Ultraviolet radiation can cause a fluorescent object to glow, to emit light, like glow in the dark decorations that they absorb ultraviolet, which you can't see, and they emit visible light slowly.

X-rays cause a chemical reaction that develops photographic film.

That's how an X-ray photograph works.

X-ray radiation causes a chemical reaction in the photographic film that changes the colour and gamma radiation destroys cancer cells.

So that's five really clear examples of energy being transferred by electromagnetic waves being absorbed.

So for your first check this lesson, have a go at matching each frequency of electromagnetic wave.

The question says each type of electromagnetic wave, but remember that each type is really means a frequency range of possible frequencies that electromagnetic wave can have.

So match each type with the example of how it can transfer energy.

Pause video now and have a go at matching all seven.

Okay, I'll go through the answers now.

The best example of radio waves transferring energy was C.

Radio waves can generate an electric current in a radio aerial, for example.

When the radio wave is absorbed, it creates an electric current in the aerial showing that energy has been transferred by the radio wave.

Microwaves.

Heat water in food.

That's a good example of microwaves transferring energy, microwave frequencies.

Infrared waves heat up the surface of an object.

That's answered.

G.

Light waves, they can generate electricity in solar panels.

That's a really good example of energy transfer by visible light.

Number five, ultraviolet rays, they cause sunburn.

So that is a good example of how it can transfer energy and cause chemical changes within your skin.

Number six, X-rays develop photographic film in hospitals.

And then gamma rays can destroy cancer cells.

So very well done if you've got most or all of those right.

Time for a new idea now about exactly how electromagnetic waves, electromagnetic radiation transfers its energy.

Now, you might have assumed that electromagnetic wave can transfer energy continuously to something as it's absorbed slowly over time that energy transferred maybe could build up.

But actually that idea is wrong.

It turns out that electromagnetic waves actually transfer their energy in small chunks or packets of energy transferred kind of one by one.

So what that means is you can picture radiation really.

And one way of picturing it could be very short bursts of electromagnetic wave arriving one after the other after the other, and each transferring their energy in turn.

So, what this means is there's like a smallest chunk of radio wave that can transfer its energy all at once.

And there's a smallest chunk of visible light that can exist of a given frequency.

And there's a smallest chunk of X-ray radiation that can exist or a smallest packet of X-rays that can transfer energy all at once.

And it turns out that the higher the frequency of the radiation, the more energy is transferred by one single packet, one single chunk of that radiation.

The smallest amount of that radiation that can exist transfers more energy if it's got highest frequency.

So that means one packet or chunk of gamma radiation will transfer more energy than one single chunk or packet of visible light radiation.

So what that means is the potential harm caused by electromagnetic radiation increases with frequency, because the higher the frequency, the more energy that can be transferred by one single chunk or packet of that radiation.

So, as we've said, that means gamma rays will transfer more energy in a single chunk in each packet of radiation than any other kind or frequency of electromagnetic wave.

However, the total amount of energy transferred by radiation depends on the intensity of that radiation as well as the frequency.

So it's not as simple as higher frequency radiation is always more dangerous.

For example, intense infrared radiation from hot charcoal that can quickly burn your skin if you put your hand close to it, not touching, just close to it.

Very intense infrared radiation could quickly burn your skin from that hot charcoal.

But a weak beam of gamma rays, even though it's high frequency and each chunk of gamma radiation, each packet of gamma radiation, carries more energy individually, because it's a weak beam, there's fewer of them.

So it's unlikely to cause harm compared to the intense infrared radiation from hot charcoal 'cause there's so many chunks being delivered, being emitted from the coals and then being absorbed by your skin every second.

It's actually transferring more energy per second.

So actually the amount of potential harm or good, because sometimes we can use this for positive effects.

So the amount of potential harm or good caused by radiation will partly depend on the frequency.

The higher the frequency, the more energy delivered by each packet of that radiation.

But it also partly depends on the total amount of energy transferred by that beam of radiation or that source of radiation in a given time.

Let's do a check on what we've just said.

Fill in the gaps using the words increases or decreases.

Pause the video to have a go at that.

Okay, let's see how you got on.

So from radio waves to gamma rays, the frequency of electromagnetic radiation increases.

And also from radio waves to gamma rays the energy transferred by each type of radiation also increases.

Again, type really could change frequency there.

The energy transferred by each frequency of radiation increases.

And it's important to remember that that is per packet of radiation.

So one packet of gamma rays, the smallest amount of gamma rays that can exist will transfer more energy than the smallest amount of any other frequency of radiation that can exist because of its higher frequency, the higher frequency, the higher the energy delivered by a single packet of that radiation.

So, we now need to look at how the energy transferred by electromagnetic radiation can cause ionisation to occur.

And we'll build this idea up really carefully.

We'll start with the idea of atoms, and of course atoms are the particles that make everything up, but of course, atoms are not the smallest kind of particle there are 'cause atoms themselves are made of protons, neutrons, and electrons.

And you have studied this before.

So we should know that atoms have no overall electric charge.

So the number of electrons, they're the particles that have negative charge in an atom, that is always exactly equal in an atom to the number of protons, which is the particle that has positive charge.

So in a lithium atom, there are three protons in the nucleus and three electrons in the shells.

So overall, three positive particles, three negative particles, no overall charge.

That is an atom and it's an atom of lithium.

This is a sodium atom.

It's got 11 protons in its nucleus.

That's 11 positively charged particles.

Because it's an atom, it also has 11 electrons, so 11 negatively charged particles.

So there's no overall charge.

And that's true for any atom by definition.

If it's got an overall charge, it can't be an atom.

Atoms have no overall charge.

The number of protons, a number of electrons, the number of positive charges, number of negative charges cancel out.

And that's in an atom.

But an atom can become an ion, but atom can be ionised if it loses or gains one or more electrons giving it an overall positive charge.

Now, in this lesson, we're gonna focus on atoms becoming ions when they lose electrons.

So for example, when this lithium atom loses an electron, like this, it becomes a lithium ion.

It's no longer an atom because it's now got three positively charged particles, three protons in the nucleus, but only two negatively charged particles.

So plus three minus two leaves you with an overall charge of plus one.

So that we say the lithium atom has been ionised, it's no longer an atom, it is now an ion.

Atoms have no overall charge.

This lithium ion now has an overall charge.

That's why it's not an atom anymore.

And its overall electric charge is plus one.

So it's got one more positively charged particle, the negatively charged particle.

Now, it's an ion.

So, that process, ionisation, can be caused by a packet of electromagnetic radiation passing by that can pull or push electrons with electric and magnetic fields because that's what electromagnetic radiation is.

Oscillations in electric and magnetic fields.

So it's the electric and magnetic fields of passing radiation, which pushes electrons off atoms. So atoms become ions.

But that can only happen, that can only be caused to happen by the higher frequencies of electromagnetic radiation because they are the only frequencies of electromagnetic radiation where the packets of radiation have enough energy to force an electron fully off an atom like this.

The electromagnetic radiation comes in.

The electron is forced off the atom, leaving behind not an atom anymore.

'Cause the number of positive charges and negative charges is no longer equal, it's now an ion.

So that is how electromagnetic radiation can cause ionisation of atoms. Let's do a check on some of the words we've just been using.

Link each of the following words, one, two, and three, to the correct definition as of A, B, and C.

Pause the video now.

Have a go at that please.

Okay, let's see how you got on.

Number one.

The word ion is definition B.

An ion is an atom that has lost or gained electrons so it's become charged.

Word number two, ionisation.

That is the name of the process of an atom losing or gaining electrons.

Ionisation has occurred if an atom has lost or gained electrons.

So that was definition C.

And that leaves number three, ionising.

There's definition A, something is ionising or the word ionising describes something that can cause atoms to lose or gain electrons.

So for example, you could say that gamma rays are ionising because gamma rays can cause atoms to lose electrons.

Gamma rays can cause atoms to become ions.

That's why gamma rays are ionising radiation.

Very well done if you've got all three of those.

So let's build on what we just said.

Ultraviolet, X-ray, and gamma ray frequencies of electromagnetic radiation are ionising.

They are the only types of electromagnetic radiation that are ionising.

All of the other frequencies of electromagnetic radiation are not ionising or non-ionizing.

So ultraviolet, X-rays, and gamma rays, they're the only types or the only frequencies of electromagnetic radiation that can ionise atoms, that can force electrons off atoms to form ions.

And that's because the higher the frequency of electromagnetic radiation, the more energy each packet carries, therefore the more likely it is to be ionising and in fact the more ionising it is.

So higher frequency gamma rays, the even more ionising, the lower frequency gamma rays, which are more ionising than X-rays, which are more ionising than ultraviolet.

And lower frequencies below ultraviolet are not ionising at all 'cause the packets of radiation don't carry enough energy.

So that just repeats what we just said.

Radio waves, microwaves, infrared, and visible light, the lower frequencies of electromagnetic wave are non-ionizing electromagnetic radiation.

And why is this dangerous? Why is ionisation linked with the potential harm? It's because if atoms in a living cell become ionised, then the cell's chemical reactions can be changed, which damages the cell.

And if the cell doesn't do its job properly, it's become a useless cell.

And if that cell is part of an important organ in your body, you want those cells to be doing their jobs, not becoming damaged.

So damaged cells may not function properly, can sometimes be killed completely.

So I want to give an important example of this, which is the atoms that make up DNA molecules.

So here is a section of a DNA molecule in a cell.

And you can see in this kind of spinning diagram the tiny balls, which the individual, in this diagram, the tiny balls represent all of the individual atoms that make up the huge DNA molecules and of course DNA molecules code for the information for every chemical reaction that happens within a cell.

So imagine if a gamma ray comes in or ionising electromagnetic radiation comes in and ionises one of the atoms within a DNA molecule, that effectively can change the instructions for a chemical reaction that happens inside your cell.

Because an atom that should be an atom might have become an ion because electromagnetic radiation came in and ionised an atom within a DNA molecule within the nucleus of the cell in a part of your body, which effectively changes the instructions for a chemical reaction inside that cell in your body can damage or potentially even kill that cell.

And then damaged cells can sometimes reproduce in an uncontrolled way and grow into a tumour or a cancer.

And tumours can prevent parts of the body from working and can sometimes sadly cause a person to die.

The amount of potential harm from ionising radiation is measured in units called sievert and that's abbreviated to a capital S and a lowercase v.

And the number of sieverts is called the radiation dose.

And here's a little table which goes through some example of radiation doses from different things.

So having one chest X-ray in a hospital is not 0.

02 millisievert.

That's what the little m means before the capital S little v.

The annual dose you'll get just from living and kind of walking around is four millisievert.

So you can see that one chest X-ray is actually absolutely tiny compared to the annual background dose you might receive from ionising radiation just from the surroundings.

And the lowest annual dose that's clearly linked to cancer risk.

So any doses higher than this are linked to cancer risk.

But any doses lower than this are not linked to cancer risk is actually 100 millisievert.

You can see that one chest X-ray does expose you to some ionising radiation, but the dose is almost 100 times less than 1% of the lowest dose, which is linked to increased cancer risk.

So radiation, the damage caused by ionising radiation of ultraviolet, X-rays, and gamma rays is actually pretty well understood and measured.

And there are some situations where exposure to ionising radiation might sound scary, but when you actually look at the measured risk, it's very, the risks are very, very, very, very, very low indeed.

I'll just add to this, that one sievert is clearly a huge amount of ionising radiation because everything in the table is in millisieverts, and it's 1,000 millisieverts that you need to make one sievert.

So because one sievert is such a huge amount of ionising radiation, radiation dose from different things is more often measured in millisieverts, which was what was used in the table.

So let's do a check on some of the things I've just said.

Which of the following types or frequencies of electromagnetic radiation is most ionising? Choose one.

A, B, or C.

This was a very simple one.

I'm sure you got the right answer, which was C, gamma rays.

Gamma rays are the most ionising kind or frequency of electromagnetic radiation because they're the highest frequency.

So the packets of radiation carry most energy and they're most likely to ionise atoms if they go close to atoms. Well done for your effort on this learning cycle so far.

So, some pupils are discussing electromagnetic radiation.

What I'd like you to do is read through what each pupil is saying and then look at the questions.

Whose idea is completely correct about ionising electromagnetic radiation? And then question two, whose ideas are incorrect about ionising electromagnetic radiation? And it might be that their answers just needs a little tweak to be correct.

So you can think about whose answers maybe fall into that category.

And then for number three, what would you say to the people whose ideas are slightly or fully incorrect to help them understand or to correct their ideas? So pause the video.

Read through what each student is saying carefully.

Think carefully about whose ideas are completely correct and whose ideas are need a bit of help, a bit feedback.

And then do some writing please to answer those questions one, two, and three.

Pause the again now.

Off you go.

Okay, I'm gonna give you some feedback now.

So whose idea is completely correct about ionising electromagnetic radiation? The answer is actually only Aisha.

All of the other three ideas need a bit of feedback.

So Aisha's idea was that electromagnetic radiation is made up of oscillating electric and magnetic fields, ripples in electric and magnetic fields.

And that's absolutely right.

That's a good way and correct way of picturing electromagnetic radiation.

So let's look at now at how the other three pupils ideas could potentially be improved.

What feedback could we give to them to help them tweak their ideas to get them right? So Jacob said that electromagnetic radiation can force protons of atoms. So atoms become ions.

He's just made a very simple slip.

Perhaps he's mixed up protons and electrons.

Electromagnetic radiation can force electrons off atoms. That's what causes ionisation.

You can't force protons outta atoms. You can force, electrons can be forced out of atoms to turn the atom into an ion.

Lucas says that ultraviolet, X-rays, and gamma rays can all ionise living cells.

Now, his mistake here is slightly more subtle.

Lucas's incorrect because cells can't be ionised, cells can't become ions.

That's a mistake.

It's atoms within cells that can be ionised.

So that's a mistake that's often seen in pupil's work.

Atoms are the things that can be ionised.

Well done if you spotted that one.

Now let's look at what Laura said.

Laura said gamma rays are more likely to ionise atoms as they have more mass and speed.

Well, Laura's right.

The gamma rays are more ionising than other electromagnetic waves, but that's because of their higher frequency.

Electromagnetic waves don't have mass and they all travel at the same speed through air.

So it's nothing to do with mass and it can't be anything to do with speed because all electromagnetic waves travel at the same speed through air.

Gamma rays are more ionising because of their higher frequency.

Very well done if you've got lots of those ideas right.

You pause the video now and make any improvements to your work to improve these pupils' ideas.

So that takes us to the second section of the lesson where we're gonna look in more detail at each kind or each of the frequencies of electromagnetic radiation that are ionising ultraviolet, X-rays, and gamma ray frequencies.

So ultraviolet or UV, X-ray, and gamma radiation are the frequencies of electromagnetic radiation, which are ionising.

And you can see the three of them at the high frequency end of the electromagnetic spectrum, the spectrum of possible frequencies of electromagnetic waves.

So ultraviolet, X-rays, and gamma rays are the highest frequencies, so the most ionising.

And they're also the shortest wavelength.

And all three of ultraviolet, X-ray, and gamma frequencies of electromagnetic wave can damage cells by ionising atoms that cells are made from.

The sun, for example, emits some ultraviolet radiation, some UV from the sun.

When skin absorbs ultraviolet, it often causes a brown pigment called melatonin to be made.

Melatonin helps protect skin cells against more ultraviolet radiation.

And that's the suntan.

A tanning bed produces ultraviolet to give a suntan, but too much ultraviolet can cause sunburn and damage your skin permanently in some cases and your eyes.

And of course sunscreen keeps you safe from the sun's ultraviolet if it's used correctly.

When a layer is applied on your skin, that absorbs ultraviolet before the ultraviolet can get to your skin.

So less will be absorbed by skin cells, reducing the risk of harm.

Fluorescent objects absorb electromagnetic radiation and emit visible light.

For example, fluorescent inks are used for security markings on valuable equipment and it's built into bank notes and bank cards and it can only be seen with a ultraviolet lamp that emits ultraviolet.

The ultraviolet radiation gets absorbed and then the ink emits visible light, which then glows.

And the inside of fluorescent lamps are coated with a fluorescent powder.

So the ultraviolet, which is emitted within the lamp, hits the powder causing the powder to glow.

And that's how these lamps give out visible light so we can light up a room.

Fluorescent lamps are much more energy efficient than traditional filament light bulbs that get so hot that they glow.

Fluorescent light bulbs don't do anywhere near as much heating.

So more of the energy, much more of the energy goes into lighting the room than heating, unlike traditional filament lamp bulbs.

LED light bulbs are even more energy efficient, but they work differently.

Ultraviolet radiation can be used to kill harmful microbes, bacteria on surfaces and in drinking water.

And that's because ultraviolet radiation is ionising so it can damage cells.

Gamma radiation could be more even more effective for this purpose because it's more ionising and it can penetrate further into food to kill microbes under the surface.

So gamma radiation can be used to irradiate food and sterilised medical equipment.

Irradiated food stays fresher for longer than normal food and the food itself does not become radioactive.

It's just irradiated.

State if each of the following statements refer to ultraviolet radiation, gamma rays, or both.

Pause video now and have a go at that.

Okay, let's see how you got on.

Ionising radiation applies to both ultraviolet and gamma rays.

It can cause atoms to lose electrons, it can cause ionisation or that applies to both.

It is absorbed by skin.

That's ultraviolet only.

Gamma rays can pass through skin.

It's used to disinfect water.

That's ultraviolet.

It's used to sterilise medical equipment.

That's gamma rays.

It causes fluorescent.

That tends to be ultraviolet.

Well done if you've got those right.

So let's talk about X-rays now.

X-ray radiation is absorbed by bone but it can pass through skin, another soft tissue.

So X-ray radiation can be used to photograph bones inside a living body.

So X-rays passing through less dense materials, skin, soft tissue, muscle tissue, that's shown on X-ray photographs like this as black.

And the white parts are the bones where no X-rays got through because they were absorbed.

So X-ray machines at security checks can detect metal objects inside luggage in the same way.

So X-rays are absorbed by more dense materials like bone and by sheets of metal and sheets of lead.

And that's used in protective clothing and screens in hospitals, near X-ray machines.

Gamma rays are also often used for medical imaging.

Radioactive materials that emit gamma radiation are sometimes injected into a person.

Gamma radiation emitted from inside the body can then be detected and used to generate images of internal organs.

Gamma radiation can also be used to kill cancer cells in a tumour, and that's called radiotherapy.

Several beams are targeted on the cancer cells.

Energy from all the beams is transferred to the cancer cells, but the surrounding healthy tissue, they're only affected by a single beam.

So it's a way of making sure that a tumour gets the full dose from all the beams, but the healthy tissue is as affected as little as possible.

Let's do a check on some of these uses of ionising electromagnetic radiation that we've gone through.

Which of the following can ultraviolet, X-ray, or gamma radiation do to matter? So if one of the kinds of radiation can do it, then tick it.

If none of the kinds of radiation can do it, then cross it.

Pause the video now and have a go for each one.

Okay, let's see how you got on.

Here are the answers.

So it turns out that ionising electromagnetic radiation, so ultraviolet, X-ray, or gamma frequencies of electromagnetic radiation can do all of these things apart from ionised cells.

And of course that's the mistake we talked about earlier.

Cells are not the things that can be ionised.

Atoms are what can be ionised.

Okay? Atoms that make up cells or atoms within cells can be ionised.

So ionising electromagnetic radiation can do all of the other seven things.

It can pasture it through some solid materials.

It can be absorbed and heat materials.

It can kill or deactivate microbes, bacteria.

It can damage cells.

It can help to detect cancer.

It can treat cancer.

And it can also increase the risk of cancer because it's ionising.

Well done if you got all of that right.

So all frequencies of electromagnetic radiation can originate from changes that occur within atoms. For example, here's a lithium atom.

When atoms absorb radiation, energy can be transferred to an electron that allows it to move to a higher energy level or to a different shell.

So have a look at this animation here.

Electromagnetic wave comes in and is can transfer energy to an electron, moving it up one energy level and then that's called an excited atom with an electron that's been bumped up an energy level 'cause it's absorbs some energy from radiation.

Note that you could say that the electron's been excited.

You could also say the entire atom has been excited.

The atom is now in an excited state with the electron bumped up one energy level.

But then what can happen is excited electrons can then transfer energy away from an atom by emitting electromagnetic radiation up to the frequency of X-rays, that is.

So watch the animation.

Watch that top excited electron and it's gonna drop back down now by emitting electromagnetic radiation.

Off it goes.

And now, it's no longer an excited atom.

It's back in its kind of normal or ground state.

So we said that is how all atoms can give out different frequencies of electromagnetic radiation up to X-rays.

Gamma rays are different.

That's why we're mentioning this now in the this part of the lesson, focusing just on gamma rays.

So gamma rays can't be emitted in that way.

Gamma rays instead originate from changes within the nucleus of atoms. Let's do a check on what we've just said.

Which of the following types of electromagnetic radiation can be emitted by excited electrons? Tick the ones you think.

Off you go.

Five seconds.

Okay, here's the answer to this.

It's only ultraviolet and X-ray radiation.

Gamma ray electromagnetic radiation can't be emitted from excited electrons when they drop back down.

Gamma radiation is emitted from changes in the nucleus of atoms instead.

So, here is a final task for this lesson.

I would like you please to fill in this table to summarise the properties of ultraviolet radiation, X-ray radiation, and gamma ray frequencies of electromagnetic radiation.

You might need to make some of these boxes bigger to fit in all the information that would be useful to have a note of.

Pause the video now and have a good go at this task.

Well done for your effort on that task.

Let's see how you got on.

So ultraviolet, X-rays, and gamma rays.

What are they? They're electromagnetic waves with higher frequencies and shorter wavelengths than visible light.

And from ultraviolet to gamma, frequency increases and wavelength decreases.

The speed in air is 300 million metres per second.

How ionising is each one while ultraviolet is moderately ionising, and then the ionising ability increases.

So X-rays are strongly ionising and gamma rays are very strongly ionising.

Specific dangers.

Well, for all three, the risk of cell damage or cancer increases with exposure to all three of them.

But specific dangers for ultraviolet might include sunburn, skin cancer, and eye conditions, and premature skin ageing as well.

Whereas X-rays and gamma rays, it's perhaps a bit similar to describe, the specific dangers would be damaged to cells in the human body and maybe even mutations to DNA.

Some example uses, example sources, and example absorbers are summarised in this table.

And you could pause the video to make a note of any that you missed in your table.

So here's a summary of the lesson on ionising electromagnetic radiation.

All electromagnetic waves can transfer energy.

They transfer energy in small chunks or packets.

The higher the frequency, the more energy is transferred by a single packet of radiation.

Ultraviolet, X-ray, and gamma are the types of frequencies of ionising radiation.

Ionising radiation can damage or destroy cells and increase the risk of cancer.

The higher the frequency, the more ionising the electromagnetic radiation is.

Ultraviolet radiation can cause tanning and sunburn.

It can speed up skin ageing and cause eye conditions and skin cancer.

It's used in fluorescent lighting, security marking, and for disinfecting water.

X-rays and gamma rays are used in medical imaging.

Gamma rays are used to kill cancer cells and also to sterilise medical equipment and food.