Light waves, visible and invisible

00:05:58
https://www.youtube.com/watch?v=O0PawPSdk28

Ringkasan

TLDRThe video explores the concept of perceiving only one color, akin to only seeing red while everything else is invisible. It compares this to how humans see a limited spectrum of light due to human eye limitations. We are surrounded by various types of light, such as radio waves, x-rays, and microwaves, that are invisible to us. Light is electromagnetic radiation that behaves both as a wave and a particle; its different wavelengths determine what we can perceive. The human brain perceives colors through cones and rods in the retina, which react to different light energies. Visible light comprises a tiny part of the electromagnetic spectrum. Special detectors and telescopes expand our "vision" to other wavelengths, allowing scientists to observe the universe beyond visible light, enabling a broader understanding of natural phenomena both on Earth and in the universe.

Takeaways

  • 🔴 Humans perceive only a fraction of the light spectrum as visible light.
  • 🌊 Light behaves both as a wave and a particle, affecting its energy.
  • 👁️ Our eyes use rods and cones to detect energy levels and colors.
  • 🌈 Visible light spectrum consists of wavelengths our eye can measure.
  • 🌌 The universe emits the full light spectrum, most of it invisible to human eyes.
  • 📡 Special detectors can "see" light wavelengths our eyes can't detect.
  • 🔬 Different light wavelengths help us understand distant space phenomena.
  • 🛰️ Space telescopes like Hubble enhance our view of the universe.
  • 🎨 Visible light is just a small palette of color in the universe's picture.
  • 🔍 Understanding light can enhance our perception of the natural world every day.

Garis waktu

  • 00:00:00 - 00:05:58

    Your eyes can only perceive a small portion of the electromagnetic spectrum, referred to as visible light. Different types of light waves have different wavelengths and frequencies, which determine their energy. Your retina contains cones sensitive to different energies, allowing you to see colors depending on light energy. Light outside the visible range, such as radio waves or x-rays, cannot be seen due to its wavelength, but special devices can detect it. The universe emits the entire spectrum of light, which can be observed with specialized telescopes, providing insights into distant cosmic events. Understanding light's properties enables us to comprehend phenomena both on Earth and in space.

Peta Pikiran

Video Tanya Jawab

  • What is visible light?

    Visible light is the small range of electromagnetic radiation that human eyes can detect.

  • How do we perceive different colors?

    We perceive colors due to cones and rods in the retina, reacting to different energies of light.

  • Why can't we see all types of light?

    Human eyes can only detect a specific range of light energies; other wavelengths are either too high or too low for our eyes.

  • What is the importance of telescopes in observing the universe?

    Telescopes allow us to observe light wavelengths beyond the visible spectrum, enhancing our understanding of the universe.

  • Why is the study of different light wavelengths crucial?

    Studying different wavelengths helps us understand various phenomena both on Earth and in distant space.

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Gulir Otomatis:
  • 00:00:07
    What if you could only see one color?
  • 00:00:09
    Imagine, for instance,
  • 00:00:11
    that you could only see things that were red
  • 00:00:13
    and that everything else
  • 00:00:14
    was completely invisible to you.
  • 00:00:17
    As it turns out,
  • 00:00:18
    that's how you live your life all the time
  • 00:00:20
    because your eyes can only see
  • 00:00:21
    a minuscule part of the full spectrum of light.
  • 00:00:25
    Different kinds of light are all around you everyday
  • 00:00:28
    but are invisible to the human eye,
  • 00:00:30
    from the radio waves that carry your favorite songs,
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    to the x-rays doctors use to see inside of you,
  • 00:00:35
    to the microwaves that heat up your food.
  • 00:00:38
    In order to understand
  • 00:00:39
    how these can all be light,
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    we'll need to know a thing or two
  • 00:00:42
    about what light is.
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    Light is electromagnetic radiation
  • 00:00:46
    that acts like both a wave and a particle.
  • 00:00:49
    Light waves are kind of like waves on the ocean.
  • 00:00:52
    There are big waves and small waves,
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    waves that crash on the shore
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    one right after the other,
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    and waves that only roll in every so often.
  • 00:01:00
    The size of a wave is called its wavelength,
  • 00:01:02
    and how often it comes by
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    is called its frequency.
  • 00:01:06
    Imagine being a boat in that ocean,
  • 00:01:08
    bobbing up and down as the waves go by.
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    If the waves that day have long wavelengths,
  • 00:01:13
    they'll make you bob only so often,
  • 00:01:15
    or at a low frequency.
  • 00:01:17
    If the waves, instead, have short wavelengths,
  • 00:01:20
    they'll be close together,
  • 00:01:21
    and you'll bob up and down much more often,
  • 00:01:23
    at a high frequency.
  • 00:01:25
    Different kinds of light are all waves,
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    they just have different wavelengths and frequencies.
  • 00:01:31
    If you know the wavelength or frequency
  • 00:01:33
    of a wave of light,
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    you can also figure out its energy.
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    Long wavelengths have low energies,
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    while short wavelengths have high energies.
  • 00:01:41
    It's easy to remember
  • 00:01:42
    if you think about being in that boat.
  • 00:01:44
    If you were out sailing on a day
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    with short, choppy waves,
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    you'd probably be pretty high energy yourself,
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    running around to keep things from falling over.
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    But on a long wavelength sea,
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    you'd be rolling along, relaxed,
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    low energy.
  • 00:01:59
    The energy of light tells us
  • 00:02:00
    how it will interact with matter,
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    for example, the cells of our eyes.
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    When we see, it's because the energy of light
  • 00:02:07
    stimulates a receptor in our eye
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    called the retina.
  • 00:02:11
    Our retina are only sensitive to light
  • 00:02:13
    with a very small range in energy,
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    and so we call that range of light visible light.
  • 00:02:18
    Inside our retina are special receptors
  • 00:02:20
    called rods and cones.
  • 00:02:22
    The rods measure brightness,
  • 00:02:24
    so we know how much light there is.
  • 00:02:26
    The cones are in charge of what color of light we see
  • 00:02:29
    because different cones are sensitive
  • 00:02:31
    to different energies of light.
  • 00:02:33
    Some cones are more excited by light
  • 00:02:35
    that is long wavelength and low energy,
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    and other cones are more excited
  • 00:02:39
    by short wavelength, high-energy light.
  • 00:02:42
    When light hits our eye,
  • 00:02:43
    the relative amount of energy each cone measures
  • 00:02:46
    signals our brain to perceive colors.
  • 00:02:48
    The rainbow we perceive
  • 00:02:50
    is actually visible light in order of its energy.
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    At one side of the rainbow
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    is low-energy light we see as red,
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    and at the other side is high-energy light
  • 00:02:59
    we see as blue.
  • 00:03:01
    If light shines on us
  • 00:03:02
    that has an energy our retina can't measure,
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    we won't be able to see it.
  • 00:03:07
    Light that is too short wavelength or high energy
  • 00:03:09
    gets absorbed by the eye's surface
  • 00:03:11
    before it can even get to the retina,
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    and light that is too long wavelength
  • 00:03:16
    doesn't have enough energy
  • 00:03:17
    to stimulate our retina at all.
  • 00:03:19
    The only thing that makes one kind of light
  • 00:03:21
    different from another is its wavelength.
  • 00:03:24
    Radio waves have long wavelengths,
  • 00:03:26
    while x-rays have short wavelengths.
  • 00:03:28
    And visible light, the kind you can actually see,
  • 00:03:30
    is somewhere in between.
  • 00:03:33
    Even though our eyes can't detect light
  • 00:03:35
    outside of the visible range,
  • 00:03:37
    we can build special detectors
  • 00:03:38
    that are stimulated
  • 00:03:39
    by these other wavelengths of light,
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    kind of like digital eyes.
  • 00:03:43
    With these devices,
  • 00:03:44
    we can measure the light that is there,
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    even though we can't see it ourselves.
  • 00:03:50
    So, take a step back and think about
  • 00:03:51
    all of this for a moment.
  • 00:03:53
    Even though they seem different,
  • 00:03:54
    the warmth you feel from a crackling fire
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    is the same as the sun shining on you
  • 00:03:58
    on a beautiful day,
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    the same as ultraviolet light
  • 00:04:01
    you put on sunscreen to protect yourself from,
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    the same thing as your TV,
  • 00:04:05
    your radio,
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    and your microwave.
  • 00:04:09
    Now, those examples are all things here on Earth,
  • 00:04:11
    things you experience in your everyday life,
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    but here's something even more amazing.
  • 00:04:16
    Our universe gives off the full spectrum of light, too.
  • 00:04:20
    When you think of the night sky,
  • 00:04:22
    you probably think of being able
  • 00:04:24
    to see the stars shining with your own eyes,
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    but that's just visible light,
  • 00:04:28
    which you now know is only a tiny part
  • 00:04:30
    of the full spectrum.
  • 00:04:31
    If we had to draw the universe
  • 00:04:33
    and could only use visible light,
  • 00:04:35
    it would be like having only one crayon --
  • 00:04:37
    pretty sad.
  • 00:04:39
    To see the universe in its full spectrum,
  • 00:04:41
    we need to have the right eyes,
  • 00:04:43
    and that means using special telescopes
  • 00:04:45
    that can help us see beyond visible light.
  • 00:04:48
    You've probably heard of the Hubble Space Telescope
  • 00:04:50
    and seen its beautiful pictures
  • 00:04:51
    taken in visible and ultraviolet light.
  • 00:04:54
    But you might not know
  • 00:04:55
    that there are 20 space telescopes in orbit,
  • 00:04:58
    missions that can each see part
  • 00:05:00
    of the full spectrum of light.
  • 00:05:02
    With telescopes acting as our virtual eyes,
  • 00:05:04
    both in space and here on Earth,
  • 00:05:06
    we can see some amazing things.
  • 00:05:09
    And the coolest thing of all,
  • 00:05:10
    no matter the wavelength or energy,
  • 00:05:13
    the light that we see out in the distant universe
  • 00:05:15
    is the same thing as the light
  • 00:05:17
    that we can experience and study here on Earth.
  • 00:05:19
    So, since we know the physics
  • 00:05:20
    of how x-ray,
  • 00:05:22
    ultraviolet light,
  • 00:05:23
    or microwaves work here,
  • 00:05:25
    we can study the light of a distant star or galaxy
  • 00:05:28
    and know what kinds of things
  • 00:05:29
    are happening there too.
  • 00:05:31
    So, as you go about your daily life,
  • 00:05:33
    think beyond what your eyes can and can't see.
  • 00:05:35
    Knowing just a little bit about the natural world
  • 00:05:38
    can help you perceive the full spectrum
  • 00:05:40
    around you all the time.
Tags
  • light spectrum
  • visible light
  • electromagnetic radiation
  • wavelength
  • cones and rods
  • retina
  • invisible light
  • space telescopes
  • universe
  • radio waves