Visible Light vs Infrared: What Is the Difference?

visible light vs infrared

Visible Light vs Infrared: What Is the Difference?

Last year, NASA launched its new flagship telescope. With the ability to view the universe in the infrared (IR) spectrum, the James Webb Space Telescope can peer through space dust and has the longest range in history. However, without visible light, we’d have no idea what those celestial objects looked like. 

Comparing visible light vs infrared can prove challenging; while they share similar qualities, they do wildly different things. Continue reading for everything you should know about these two electromagnetic frequencies.

Visible Light vs Infrared: Side-by-Side Comparison

Visible LightInfrared
Discovery Date16651800
Discovered BySir Isaac NewtonWilliam Herschel
Frequency790 to 400THz300Ghz – 400THz
Wavelength380 (violet) – 700nm (red)780nm – 1mm
Energy Level3.3 to 1.7eV1.2meV – 1.7eV
ApplicationsA variety of lighting solutionsNight vision, tracking, heating and cooling, communications, meteorology, astronomy
Possible HazardsDetriment to sleep quality with certain wavelengthsDamage to the eyes

Visible Light vs Infrared: What’s the Difference?

Visible Light Origin

While researchers were experimenting with the theory of visible light as early as the 13th century, it wasn’t until 1665 that it was physically tested. Using a glass prism, English physicist Sir Isaac Newton discovered that some sunlight, when directed at it, would pass through and split into separate colors.

He theorized that each color made up white light and that they traveled at different speeds when traveling through the prism. Solidified as part of the whole spectrum of electromagnetic waves in 1802, visible light is emitted from objects as they heat up.

This occurs when an object’s composition activates, causing its atoms to activate. Regarding the visible light spectrum, researchers can use the color of the light to tell how hot an object is.

Visible Light Spectrum

visible light vs infrared
Visible light is electromagnetic radiation that can be perceived by the human eye.

The visible light range is found between IR and ultraviolet on the electromagnetic spectrum. Similar to its radiant neighbors, visible light is typically measured using its wavelength. Sometimes, however, researchers will refer to it by its frequency.

This portion of the EM spectrum is the smallest by a large margin; the wavelength that we can see with our naked eye only ranges from about 380 (violet) to 700nm (red). This correlates with a frequency of 790 to 400 THz and an energy level of 3.3 to 1.7eV. For reference, the average wavelength of visible light measures the thickness of a bubble’s membrane. 

Visible Light Applications

Due to its incredibly short range, the use of visible light frequencies is pretty limited. However, that’s not to say it’s not important; without the visible light spectrum, we wouldn’t be able to see.

As such, this type of radiation presents itself in a variety of lighting applications. Additionally, researchers can use this spectrum to associate temperature with certain objects.

Visible Light Dangers

Alongside its lack of applications, the concise range of visible light doesn’t open it up to producing adverse effects. Currently, scientists at Harvard Health are studying the relationship between blue light and the health of our eyes.

Some studies show that exposure to blue light can cause problems sleeping. This is a common factor to consider as our phones and computer screens emit this frequency.

Infrared Origin

The first “heat wave” was discovered in 1800 by German-British astronomer William Herschel. The researcher used a prism, the same as Newton’s, to display each color of light. Using a piece of cardboard with a slit, he was able to measure the temperature of each color.

When testing the temperature outside of the red frequency, Herschel discovered that it continued to rise. This led him to believe that temperature wasn’t caused by illumination but by waves. Based on the astronomer’s experiments, IR radiation comes from objects that produce heat.

The heat-creating objects are less hot in this range compared to visible light, but because the wavelengths are longer, their temperature is more noticeable. In fact, it doesn’t require a lot of heat to produce infrared; the radiation can be emitted from any object with a thermal temperature as low as minus 450 degrees Fahrenheit.

Infrared Spectrum

visible light vs infrared
Infrared light is electromagnetic radiation with wavelengths longer than those of visible light.

As mentioned above, IR finds its place on the electromagnetic spectrum adjacent to the red portion of visible light. However, its frequencies are quick enough to differentiate from radio and microwaves. Researchers tend to refer to IR based on its frequency, and wavelengths due to its low energy.

This type of radiation typically ranges from 780nm – 1mm in wavelength. This correlates with a frequency range of 300Ghz – 400THz and an energy level of 1.2meV – 1.7eV. Compared to visible light, IR is much longer; the average wavelength measures the diameter of a human hair.

Infrared Applications

Unlike visible light, infrared radiation has a wide range of frequencies that allow it to be applied to several functions. Most prominently, IR is known for its use in night vision goggles, which paint a visible image based on different wavelengths.

More commonly, this type of radiation is found in several household objects. This includes your toaster oven, television remote, and garage door opener.

Infrared Dangers

Despite its frequency range, infrared light is also pretty safe. IR radiation is not powerful enough to ionize like other portions of the EM spectrum. And while they’re often associated with heat, they won’t cause burns. In some cases, however, focused exposure to high-frequency infrared can cause damage to the retinas in your eyes and even result in blindness.

Visible Light vs Infrared: 5 Must-Know Facts

  1. Infrared and the red portion of visible light share similar frequencies.
  2. While these two types of radiation are located next to each other, infrared is not visible to the naked eye.
  3. Without visible light, we would not be able to see the objects in front of us.
  4. Both of these frequencies are non-ionizing, making them relatively safe in typical exposure.
  5. The James Webb Space Telescope uses infrared to view as far back as 13.6 billion lightyears into the universe.

Visible Light vs Infrared: Which One Is Better?

Comparing visible light vs infrared is a little more subjective than some other frequencies. Both of these types of radiation share similar wavelengths and energy levels. Neither of them is so intense that they’ll cause significant harm. Therefore, the biggest difference comes from their applications.

Counting the sheer number of uses, IR light takes the cake; with functions in several areas including thermal imaging, heating and cooling, and communications, IR technology helps us out over a much wider range. However, we could not see the objects in front of us without visible light. As far as magnitude goes, this type of radiation makes a good claim for better frequency.

Visible Light vs Infrared: Further Reading

As close as these two frequencies sit on the electromagnetic spectrum, it’s essential to know the differences between visible light vs infrared. While they have similar qualities, these types of radiation bring entirely different qualities to the table. For more on how the electromagnetic spectrum influences us, check out the articles below.

Frequently Asked Questions

Is infrared stronger than visible light?

Comparatively, infrared has a longer wavelength and a lower photon energy level than visible light. This makes IR less powerful than visible light.

Is infrared considered visible light?

While infrared shares similar frequencies with the red portion of visible light, it is invisible to the naked eye. Therefore, IR is not considered visible light.

Can infrared see through the dark?

Using sensors that look for infrared frequencies, night vision goggles can paint a picture of an object even in the dark.

Can infrared see people through walls?

While infrared is useful for seeing in the dark, its frequency is not strong enough to pierce through objects. Therefore, it won’t see people through walls.

What is infrared used for?

Infrared is used in a variety of applications, including thermal imaging, heating and cooling, communications, astronomy, and more.

How do we use visible light?

Because of its incredibly short frequency range, visible light is not widely used. However, it does find application in many different lighting solutions.

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