Electromagnetic Radiation

Summary

This educational video script explores how scientists determine the chemical composition of celestial objects like the sun, which is 150 million km away. It explains the concept of spectroscopy using a simple homemade spectrometer made from a cardboard tube and an old CD, demonstrating how white light is split into a spectrum of colors. The script further explains how each element emits and absorbs specific wavelengths of light, which is key to understanding the sun's composition. By analyzing the absorption spectrum of the sun, scientists can deduce its elements, such as hydrogen (70%), helium (28%), and trace amounts of nitrogen, oxygen, and iron. The script also touches on how this method is used to study distant stars, revealing the diversity of stars in our universe.

Takeaways

• 🌍 Scientists on Earth can determine the chemical composition of objects, even those far away like the Sun.
• 🚗 The Sun is 150 million km away, and even the fastest car on Earth would take over 40 years to reach it.
• 🔬 A simple homemade spectrometer using a cardboard tube and an old CD can demonstrate the principle of light dispersion.
• 🌈 White light can be split into different colors, similar to a rainbow, using a spectrometer.
• 🔦 An LED light can be used to enhance the visibility of the different colors when using a homemade spectrometer.
• 🔬 Scientists use similar equipment to observe the light emitted from the Sun to determine its chemical composition.
• 🔥 Burning elements produce characteristic colors, which can be used to identify them, similar to how the Sun's composition is analyzed.
• 🌞 The Sun's absorption spectrum shows dark lines that correspond to wavelengths absorbed by elements present in its atmosphere.
• 🧪 The Sun is primarily composed of hydrogen (about 70%) and helium (about 28%), with trace amounts of other elements like nitrogen, oxygen, and iron.
• 🌠 By analyzing the spectra of distant stars, scientists can determine their chemical compositions, leading to discoveries about different types of stars in the universe.

Q & A

What is the distance between Earth and the Sun?

The Sun is approximately 150 million kilometers away from Earth.

How long would it take for the fastest car on Earth to reach the Sun if it could travel in a straight line?

Even at a speed of 430 km/h, it would take over 40 years for the fastest car on Earth to reach the Sun.

What is a simple way to demonstrate the dispersion of light into its constituent colors?

A simple way to demonstrate light dispersion is by using a cardboard tube and an old CD, which can split white light into different colors, similar to a rainbow.

How can a homemade spectrometer help in understanding the composition of the Sun?

A homemade spectrometer can help by observing the light being emitted from the Sun. It allows us to see the absorption spectrum, which shows the wavelengths of light absorbed by elements present in the Sun.

What is the significance of the different colors seen in a flame when burning different elements?

Different elements produce characteristic colors in a flame due to the light they emit. For example, potassium gives a lilac flame, lithium a red flame, sodium a yellow flame, and copper a greenish-blue flame.

How does the absorption spectrum of the Sun relate to its composition?

The absorption spectrum of the Sun shows dark lines that correspond to wavelengths of light absorbed by elements present in the Sun. This helps scientists determine the Sun's composition, which includes hydrogen, helium, and trace amounts of other elements like nitrogen, oxygen, and iron.

What percentage of the Sun's composition is made up of hydrogen and helium?

The Sun is composed of approximately 70% hydrogen and 28% helium.

How can the technique of observing light spectra be used to analyze distant stars?

By observing the light spectra of distant stars, scientists can determine the elements present in their atmospheres, as each element emits and absorbs specific wavelengths of light.

What is the purpose of using an LED light in the homemade spectrometer demonstration?

An LED light is used to provide a bright white light, which contains all the different colors of the spectrum. This light is then split into its constituent colors by the spectrometer, making it easier to observe the spectrum.

How do the dark lines in the Sun's spectrum indicate the presence of elements?

The dark lines in the Sun's spectrum indicate the presence of elements because these lines represent wavelengths of light that are absorbed by those elements as the light passes through the Sun's atmosphere.

Outlines

00:00

🌞 Understanding the Sun's Composition

The paragraph discusses the challenge of analyzing the chemical composition of objects that are far away, like the Sun, which is 150 million kilometers from Earth. It explains that even the fastest car on Earth would take over 40 years to reach the Sun. The script then introduces a simple homemade spectrometer made from a cardboard tube and an old CD to demonstrate how white light can be split into different colors, similar to a rainbow. This device is used to show how scientists observe the light emitted from the Sun to determine its composition. The paragraph also explains how different elements emit specific colors when burned, which is used to identify their presence in the Sun's atmosphere through the absorption spectrum.

Keywords

💡Chemical Composition

Chemical composition refers to the elements and compounds that make up a substance. In the context of the video, scientists are interested in determining the chemical composition of the sun, which is a significant challenge due to its immense distance from Earth. The video discusses how scientists use the absorption spectrum of the sun to deduce its chemical makeup, which includes elements like hydrogen, helium, nitrogen, oxygen, and iron.

💡Spectrometer

A spectrometer is an instrument used to measure properties of light over a specific portion of the electromagnetic spectrum. The video uses a homemade spectrometer made from a cardboard tube and an old CD to demonstrate how white light can be split into its constituent colors, similar to how scientists observe the sun's light to determine its composition.

💡Spectrum

A spectrum is a band of colors that ranges from red to violet when white light is dispersed, like in a rainbow. In the video, the spectrum is used to show how different elements emit light of specific colors when burned and how the sun's spectrum reveals its composition through the dark lines that represent wavelengths absorbed by elements present in the sun.

💡Absorption Spectrum

An absorption spectrum is a spectrum that shows the wavelengths of light that are absorbed by a substance. The video explains that the dark lines in the sun's absorption spectrum indicate the presence of certain elements because these lines correspond to the wavelengths of light that are absorbed by those elements.

💡Hydrogen

Hydrogen is the lightest and most abundant chemical element, making up about 70% of the sun's composition as mentioned in the video. It's a key element in understanding the sun's makeup and plays a crucial role in nuclear fusion reactions that power the sun.

💡Helium

Helium is a lighter-than-air noble gas that constitutes about 28% of the sun's composition, as discussed in the video. It's formed through the fusion of hydrogen nuclei in the sun's core and is second only to hydrogen in abundance within the sun.

💡Nitrogen

Nitrogen is a chemical element that is present in smaller quantities in the sun, as indicated in the video. It's one of the elements that, when present, absorbs certain wavelengths of light, which is observable in the sun's absorption spectrum.

💡Oxygen

Oxygen, like nitrogen, is another element found in smaller quantities in the sun's atmosphere. The video mentions that it, along with other elements, is identified through the analysis of the sun's absorption spectrum.

💡Iron

Iron is a metallic element that, although present in small amounts, contributes to the sun's composition. The video explains that the absorption spectrum reveals the presence of iron through the dark lines that correspond to wavelengths absorbed by this element.

💡LED Light

An LED (Light Emitting Diode) light is a type of lighting that emits a narrow spectrum of light. In the video, an LED light is used to provide a bright white light that, when passed through the homemade spectrometer, helps demonstrate the dispersion of light into its constituent colors.

💡Characteristic Color

Characteristic color refers to the specific color emitted by a substance when it is heated or burned. The video uses the example of different elements emitting different colors when burned to illustrate how each element has a unique spectral signature that can be used to identify it.

Highlights

Scientists can work out the chemical composition of objects that are thousands of kilometers away.

The sun is 150 million kilometers away from Earth, making direct travel to it impossible with current technology.

Even at a speed of 430 km/h, it would take more than 40 years to reach the sun.

A simple spectrometer can be made with a cardboard tube and a CD to split white light into different colors.

A demonstration shows how white light can be split into the colors of the rainbow using a CD and light.

Scientists use a similar method to observe the light emitted from the sun and determine its composition.

Different elements burn in distinct colors: potassium gives a lilac flame, lithium gives a red flame, sodium gives a yellow flame, and copper gives a greenish-blue flame.

Elements emit and absorb light at the same wavelengths, which helps identify their presence.

The absorption spectrum of the sun shows dark lines where specific wavelengths of light are absorbed by elements in the sun.

The dark lines in the sun’s spectrum correspond to elements such as hydrogen, helium, nitrogen, oxygen, and iron.

The sun is composed of about 70% hydrogen, 28% helium, and trace amounts of other elements.

Scientists can use the same spectrum analysis technique to study distant stars and determine their compositions.

This method of spectrum analysis has led to important discoveries about stars in the universe.

Many stars are quite different from the sun in terms of their elemental compositions.

Using spectrometry, scientists can analyze light emitted or absorbed by elements, helping them learn about distant celestial objects.

Transcripts

on earth scientists can work out the

chemical composition of most objects but

what do they do if the object is

thousands of kilometers

away the sun is our nearest star and

it's a staggering 150 million km away

now the fastest car on planet earth goes

up 430 km power but even at that speed

directly to the sun it would still take

us more than 40 years to get there now I

haven't got a car that goes anywhere

near that speed so how are we going to

find out what it's made of in 5

minutes well I reckon I can get halfway

there with this cardboard tube and an

old

CD have you ever seen a demonstration

where white light has been split into

loads of different colors red orange

yellow green blue like a

oh yes it is exactly a rainbow but you

can also do it using a tube and a CD

that don't look on the other side you

don't want to see the music that I

listen to and if we use this special

device like that what we can do is if

you look through that hole at the CD

you'll be able to see kind of different

colors so I'll let you all have a

go and point it around see if you can

EXT the light I don't know how to do

this I've got another way to make it a

bit brighter so this is an LED light and

that will give you the nice white light

that's consists of all the different

colors like that so if we shine that

through the ends now you might be able

to see it a bit better yeah know I can

see it can you see all the different

colors oh my gosh yeah that is so cool

start making your own

rainbow this simple homemade

spectrometer is surprisingly similar to

the equipment scientists have used to

observe the the light being emitted from

the Sun and we can learn more about the

light that the sun emits on Earth by

observing the colors produced in the

Flames of burning elements while burning

compounds containing different elements

we can see that they each have their own

characteristic

color potassium gives a lilac

Flame lithium gives a red flame sodium

gives a yellow flame whereas copper

gives a greenish blue flame now each

element not only emits a certain type of

light it will also absorb the exact same

color of

light it's because of the light given

off by the elements reacting that we are

able to know what the Sun's made of this

is an absorption spectrum of the sun

it's just like the Spectrum saw earlier

but it's a lot more detailed these dark

lines show a light of certain wav

lengths is absorbed by the elements

present in the

sun we know that elements Emit and

absorb the same wavelengths of light so

this means the dark lines also

correspond to wavelengths being emitted

by the

Sun as white light passes through the

sun's atmosphere some wav lengths are

absorbed by atoms of the elements that

are present

this means that the light that reaches

us from the Sun is missing some wav

lengths which corresponds to an element

in the sun's

atmosphere so the dark lines in the

Spectra of the sun show that it's made

of hydrogen about

70% helium about 28% and elements such

as nitrogen oxygen and iron in much

smaller quantities if you look at the

Spectrum of any distant star we can work

out what they're made of too this has

helped scientists make some amazing

discoveries about stars in our universe

many of which are very different from

our own star the

[Music]

sun