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  • This interactive looks at the electromagnetic spectrum1. To use this interactive, move your mouse or finger over any of the labelled boxes and select to obtain more information.

    Select here for a transcript and copyright information.

    interactive image map that looks at the electromagnetic spectrum

    The electromagnetic spectrum is a classification of the Sun’s radiation2. Scientists have identified solar energy3 as a spectrum of many different wavelengths of electromagnetic rays. They have called this the electromagnetic spectrum.

    Click on each wavelength4 to learn more about the waves that make up the spectrum.

    Transcript

    Radio

    Radio waves5 have the longest wavelengths in the electromagnetic spectrum. They are used to transport information through the atmosphere6 without wires. They carry signals to your radio, television and mobile phone.

    Astronomers like Melanie Johnston-Hollitt use radio telescopes that receive radio waves emitted by planets, stars, galaxies, and nebulas to study the far reaches of the universe7.

    Image acknowledgement: Galaxies show as small radio emissions in this telescopic image by Melanie Johnston-Hollitt

    Microwave

    Microwaves8 have wavelengths that can be measured in centimetres. Microwaves are widely used in modern technology. They are used for diverse applications like heating food in a microwave oven, garage door openers, particle9 accelerators and for transmitting information from one place to another. Shorter microwaves can be used for radar10, like the Doppler radar used in weather forecasts11.

    Image acknowledgement: Andriy Popov, 123RF Ltd

    Infrared

    Infrared12 light has a range of wavelengths. ‘Near infrared’ has shorter wavelengths and is used for devices such as night vision goggles. ‘Far infrared’ has longer wavelengths and is used for things such as thermal imaging. In the thermal image above the left hand cup holds a hot drink and the right hand cup a cold drink. The coolest parts are dark blue and the hottest parts have been coloured white to signal a temperature13 of 55° Celsuis and beyond.

    Infrared can also be used for some short range ‘line of sight’ communication, such as TV remote controls.

    Image acknowledgement: University of Waikato

    Visible light

    Visible light waves are the only electromagnetic waves we can see. We see these waves as the colours of the rainbow14. Each colour has a different wavelength. Red has the longest wavelength, and violet has the shortest wavelength. When all the waves are seen together, they make white light.

    Image acknowledgement: Delcreations, 123RF Ltd

    Ultraviolet

    There are several regions to ultraviolet light in the electromagnetic spectrum, ranging in wavelength between 10 and 400 nanometres. Too much exposure to UV light15 (such as that emitted from our Sun) can cause harmful effects like sunburn. However, ultraviolet light has been used for things such as UV lasers, fluorescent lamps and disinfecting wastewater.

    Image acknowledgement: University of Waikato

    X-ray

    X-rays have one of the smallest wavelengths in the electromagnetic spectrum. They have higher energy than ultraviolet light, but longer wavelengths than gamma rays. X-rays16 are primarily used for diagnostic radiography. They are formed through ionizing radiation, and too much exposure (the radiation is too intense and/or you are exposed for too long) can be dangerous.

    Image acknowledgement: University of Waikato

    Gamma

    Gamma rays have the smallest wavelengths in the electromagnetic spectrum. They have the most energy of any wave. The waves are generated by radioactive17 processes such as in nuclear explosions. Like other areas of the electromagnetic spectrum, they can be used to kill living cells, such as cancer18, but can provoke DNA19 alteration by interfering with the genetic20 material of the cell21.

    Image acknowledgement: A nuclear test conducted by the United States in 1953 in the Nevada Desert. Public domain.

    Rights: The University of Waikato Te Whare Wānanga o Waikato Published 29 July 2008, Updated 7 March 2018 Size: 130 KB Referencing Hub media
    1. electromagnetic spectrum: The complete range of electromagnetic radiation from the shortest waves (gamma rays) to the longest (radio waves).
    2. radiation: Energy that is transmitted (radiates) from a source in the form of rays or waves or particles.
    3. solar energy: The energy received by the Earth and from the Sun. Also called solar power.
    4. wavelength: The distance between two successive points of a wave (from one peak or crest of a wave and the next peak or crest). Usually refers to an electromagnetic wave, measured in nanometres (nm).
    5. radio waves: An electromagnetic wave having a wavelength between 1 millimetre and 30,000 metres. Radio waves are used for transmitting radio and television signals. Many celestial objects, such as pulsars, emit radio waves.
    6. atmosphere: 1. The layer of gas around the Earth. 2. (atm) A non-SI unit of pressure equivalent to 101.325 kPa.
    7. universe: All matter and energy, including the Earth, the galaxies and the contents of intergalactic space, regarded as a whole.
    8. microwaves: Invisible electromagnetic waves with wavelengths ranging from 1 mm to 1 m. Microwaves occur between radio and infrared waves on the electromagnetic spectrum.
    9. particle: A tiny piece of matter. A particle may refer to an atom, part of an atom, a molecule or an ion.
    10. radar: A method of detecting distant objects and determining their position, speed, or other characteristics by using very high frequency radio waves reflected from the objects’ surfaces.
    11. weather forecast: Using data to predict daily or short-term conditions such as temperature, cloud cover, precipitation and wind affecting a certain area or the estimate of a future weather event or series of events.
    12. infrared: Invisible electromagnetic radiation with a wavelength between approximately 0.75 micrometres and 1 millimetre. Infrared occurs between the red end of the visible light spectrum and microwaves. All things over a certain temperature (absolute zero) absorb and emit infrared radiation. Infrared radiation and observing technologies are used in many industries from medicine to finding people buried under rubble and by the military and others in night-vision goggles.
    13. temperature: A measure of the degree of hotness or coldness of an object or substance. Temperature is measured with a thermometer calibrated in one or more temperature scales. Kelvin scale temperature is a measure of the average energy of the molecules of a body.
    14. rainbow: When the sun shines on tiny droplets of moisture in the Earth’s atmosphere, a spectrum of light (the colours of the rainbow) appears in the sky in the form of a single arc.
    15. UV (ultra violet) light: Light that is invisible to the human eye and at a wavelength between 300–400 nanometres. UV light is what causes sun burn and can cause some types of cancer.
    16. X-ray: A form of electromagnetic radiation with a wavelength of 0.01 to 10 nanometres. X-rays are used in medical fields as an imaging technique.
    17. radioactive: Giving off energy as a result of the breaking up of nuclei of atoms. Something undergoing radioactive decay, the process by which an unstable atom emits radiation.
    18. cancer: The term for a group of more than 100 diseases in which abnormal cells divide and multiply uncontrollably.
    19. DNA: Deoxyribonucleic acid (DNA) is a molecule that contains the instructions needed for an organism to develop and function. These instructions are stored as a code made up of four chemical bases: adenine (A), guanine (G), cytosine (C) and thymine (T).
    20. genetic: Of, relating to, or determined by genes.
    21. cell: 1. Building block of the body. A human is made of millions of cells, which are adapted for different functions and can reproduce themselves exactly. 2. A simple electrolytic device that enables chemical energy to be transformed into electrical energy.
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        electromagnetic spectrum

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      2. The complete range of electromagnetic radiation from the shortest waves (gamma rays) to the longest (radio waves).

        wavelength

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      4. The distance between two successive points of a wave (from one peak or crest of a wave and the next peak or crest). Usually refers to an electromagnetic wave, measured in nanometres (nm).

        universe

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      6. All matter and energy, including the Earth, the galaxies and the contents of intergalactic space, regarded as a whole.

        radar

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      8. A method of detecting distant objects and determining their position, speed, or other characteristics by using very high frequency radio waves reflected from the objects’ surfaces.

        temperature

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      10. A measure of the degree of hotness or coldness of an object or substance. Temperature is measured with a thermometer calibrated in one or more temperature scales. Kelvin scale temperature is a measure of the average energy of the molecules of a body.

        X-ray

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      12. A form of electromagnetic radiation with a wavelength of 0.01 to 10 nanometres. X-rays are used in medical fields as an imaging technique.

        DNA

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      14. Deoxyribonucleic acid (DNA) is a molecule that contains the instructions needed for an organism to develop and function. These instructions are stored as a code made up of four chemical bases: adenine (A), guanine (G), cytosine (C) and thymine (T).

        radiation

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      16. Energy that is transmitted (radiates) from a source in the form of rays or waves or particles.

        radio waves

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      18. An electromagnetic wave having a wavelength between 1 millimetre and 30,000 metres. Radio waves are used for transmitting radio and television signals. Many celestial objects, such as pulsars, emit radio waves.

        microwaves

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      20. Invisible electromagnetic waves with wavelengths ranging from 1 mm to 1 m. Microwaves occur between radio and infrared waves on the electromagnetic spectrum.

        weather forecast

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      22. Using data to predict daily or short-term conditions such as temperature, cloud cover, precipitation and wind affecting a certain area or the estimate of a future weather event or series of events.

        rainbow

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      24. When the sun shines on tiny droplets of moisture in the Earth’s atmosphere, a spectrum of light (the colours of the rainbow) appears in the sky in the form of a single arc.

        radioactive

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      26. Giving off energy as a result of the breaking up of nuclei of atoms. Something undergoing radioactive decay, the process by which an unstable atom emits radiation.

        genetic

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      28. Of, relating to, or determined by genes.

        solar energy

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      30. The energy received by the Earth and from the Sun. Also called solar power.

        atmosphere

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      32. 1. The layer of gas around the Earth.

        2. (atm) A non-SI unit of pressure equivalent to 101.325 kPa.

        particle

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      34. A tiny piece of matter. A particle may refer to an atom, part of an atom, a molecule or an ion.

        infrared

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      36. Invisible electromagnetic radiation with a wavelength between approximately 0.75 micrometres and 1 millimetre. Infrared occurs between the red end of the visible light spectrum and microwaves. All things over a certain temperature (absolute zero) absorb and emit infrared radiation. Infrared radiation and observing technologies are used in many industries from medicine to finding people buried under rubble and by the military and others in night-vision goggles.

        UV (ultra violet) light

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      38. Light that is invisible to the human eye and at a wavelength between 300–400 nanometres. UV light is what causes sun burn and can cause some types of cancer.

        cancer

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      40. The term for a group of more than 100 diseases in which abnormal cells divide and multiply uncontrollably.

        cell

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      42. 1. Building block of the body. A human is made of millions of cells, which are adapted for different functions and can reproduce themselves exactly.

        2. A simple electrolytic device that enables chemical energy to be transformed into electrical energy.