What Things Use Light?

Light is a form of electromagnetic radiation that allows us to see the world around us. Visible light makes up only a small portion of the entire electromagnetic spectrum, ranging in wavelength from about 400 to 700 nanometers. Without light, life as we know it would not exist. Light enables plants and other organisms to undergo photosynthesis, converting light energy into chemical energy. It also allows animals, including humans, to see and visually perceive their surroundings. In addition, light has numerous technological applications that have shaped modern society.

Light is essential for vision, energy production, communication, scientific research, and much more. In this article, we will explore some of the key ways that various technologies, living organisms, and natural processes utilize light.


One of the most important uses of light is vision. Human and animal eyes use light to see the world around them. The eyes contain light-sensitive cells called rods and cones that detect light and convert it into electrical signals. These signals are sent to the brain, which interprets them as visual images.

Light enters the eye through the cornea and pupil. It then passes through the lens, which focuses the light onto the retina. The retina contains the rods and cones that detect light and transmit signals to the optic nerve. The optic nerve carries these signals to the visual cortex of the brain.

Rods are sensitive to light intensity and motion, while cones detect color. By processing the signals from the different rods and cones, the brain is able to perceive images, depth, and color. The amount, wavelength, and quality of light entering the eye determines what we are able to see. Without light, vision would be impossible.


Photosynthesis is the process plants use to convert light energy from the sun into chemical energy. During photosynthesis, plants use sunlight, carbon dioxide, and water to produce sugars and oxygen. This process is vital for life on Earth.

Plants have special structures called chloroplasts that contain chlorophyll, a pigment that absorbs light. When light strikes the chloroplast, it excites the electrons inside, providing energy to combine carbon dioxide and water to form carbohydrates. Oxygen is released as a byproduct.

Photosynthesis allows plants to harness the sun’s energy to fuel their growth and development. It also replenishes oxygen to the atmosphere, which most living organisms depend on for respiration. By harnessing light as an energy source, photosynthesis forms the basis of almost all life on Earth.

Solar Power

Solar power harnesses the sun’s energy and converts it into electricity using photovoltaic cells, commonly known as solar panels. When sunlight hits these cells, the photovoltaic material absorbs the photons, causing electrons to break free and flow through the material to produce electric current. This conversion of light into electricity is called the photovoltaic effect.

Solar panels contain a number of solar cells wired together. The more light that hits the solar cells, the more electricity that is generated. Solar panel systems can range from small-scale panels on rooftops that provide power for homes and businesses to large utility-scale solar farms containing thousands of panels spread over many acres.

Solar energy offers a clean and renewable way to generate electricity that does not create any emissions or toxic waste. Once solar panels are installed, they provide decades of service with very little maintenance required. Solar power’s potential as an alternative energy source continues to improve as technology advances and production costs decrease.

Fiber Optics

Fiber optic cables are thin glass or plastic cables that transmit data over long distances using light. Inside the cable is an extremely thin strand of very pure glass or plastic called the core. The core acts like a pipe or waveguide to keep the light contained and direct it down the length of the cable.

Lasers or LEDs at one end of the fiber optic cable produce pulses of light to represent data. This light enters the core and bounces off the walls of the core as it travels down the cable. Even though the core is very thin, typically around 10 microns wide (a human hair is 50-100 microns wide), it can carry thousands of pulses of light per second.

Fiber optic cables can transmit data over much longer distances than copper cables, with some cables transmitting data over hundreds of kilometers. They also have faster transmission speeds and suffer less signal loss over distance compared to copper cables. This makes fiber optic cables ideal for use in telecommunications networks, the internet backbone, and for connecting countries and continents.

Because fiber optic cables use light rather than electricity, they are not susceptible to electromagnetic interference like copper cables. This helps keep the data transmission secure. Fiber optic cables are used extensively in the modern information age to meet the world’s growing demand for fast, reliable data transmission.


Cameras are one of the most widely known uses of light. At their core, traditional cameras contain a light-sensitive material that captures an image when exposed to light. This allows photographers to record visual scenes from the world around them.

In modern digital cameras, an image sensor chip serves the same purpose as traditional light-sensitive films. The sensor contains millions of light-sensitive pixels that record color and brightness when exposed to light. This data is processed into a digital image file. Digital cameras allow photographs to be viewed immediately on screen and easily shared.

Without the ability of cameras to harness light, the art and science of photography would not be possible. Light is fundamental to capturing split-second moments in time or telling visual stories through images. Photographers carefully use qualities of natural and artificial light, like direction, color, and brightness, to compose their photographs. The history of photography and camera technology shows an endless pursuit to find new ways to manipulate light and improve the recording of images.


Microscopes are optical instruments that use lenses and light to produce magnified images of small objects. They allow us to see microscopic structures that are too small to observe with the naked eye. There are several different types of microscopes, but they all rely on light in some form.

The most basic optical microscope uses visible light and a system of lenses to magnify an object up to about 1,000 times its actual size. The lens closest to the object is called the objective lens and it produces a real, magnified image that is further magnified by the eyepiece lens. Most modern microscopes also use electric lighting to properly illuminate the sample being observed.

light allows us to see the world around us.

More advanced microscopes, like electron microscopes and scanning probe microscopes, use electrons or a physical probe instead of light to produce images. But even these sophisticated microscopes require some form of illumination to function. The development of microscopes revolutionized science by enabling the study of microorganisms, cells, and microscopic structures. Today, microscopes continue to be indispensable tools in many scientific fields. Their ability to use light to reveal the microscopic world plays a vital role in research and discovery.

Light Therapy

Light therapy, also known as phototherapy, is a medical treatment that utilizes light for a variety of conditions. It is emerging as an effective therapy for combating depression, sleep disorders, skin conditions and more.

One of the most common uses of light therapy is to treat seasonal affective disorder (SAD), a type of depression related to changes in seasons. SAD is associated with reduced sunlight in the winter months. Light therapy counteracts this by exposing people to artificial bright light that mimics natural outdoor light. This can greatly improve mood and energy levels.

Another application of light therapy is for skin disorders like psoriasis and eczema. Exposing skin to UV rays under medical supervision can significantly reduce inflammation and redness caused by these conditions. The controlled UV exposure allows diseased skin cells to die off and healthier skin to regenerate.

Light therapy shows promise for other autoimmune disorders as well. Some studies indicate it may help treat rheumatoid arthritis by reducing inflammation and pain in joints. The mechanisms still require further research but the results are encouraging.

In infants, light therapy is used to treat newborn jaundice. The light helps break down bilirubin deposits in the blood, which cause jaundice. This makes it a simple and non-invasive treatment.

Overall, light therapy provides a way to harness the therapeutic benefits of light for better health and wellbeing. More applications are still being researched and discovered.

Display Screens

Screens emit light in order to display images, videos, text, and other visual information. From smartphones to computer monitors to televisions, screens utilize light emission technologies like LED (light emitting diodes), OLED (organic light emitting diodes), LCD (liquid crystal display), plasma, and CRT (cathode ray tube) to produce light and color that our eyes perceive as the picture.

Pixels on the screen emit red, green, and blue light in different combinations to create the millions of colors we see. The pixels are so small and close together that they appear to blend into one coherent image to our eyes. Display technology has advanced dramatically in recent decades to produce brighter, sharper, and more vibrant images on thinner and more energy efficient screens. High dynamic range, high refresh rates, 4K and 8K resolution, and features like OLED with true blacks and vibrant colors provide ever more stunning visuals.

Screens enable us to enjoy visual entertainment, do work, communicate face-to-face from a distance, pursue creative hobbies, learn through multimedia content, and much more. The light emitted by our screens connects us with information, art, people, and new experiences. Display technology will likely continue improving in line with our insatiable appetite for brighter, crisper, and more immersive visual media.


Light has an incredibly wide range of uses that enable many critical aspects of our lives. This article explored various categories where light is instrumental, from biological functions like vision and photosynthesis, to technological applications like solar power and fiber optics, to creative outlets like photography and display screens. Light makes the natural world visible, powers sustainable energy, transmits data rapidly, reveals microscopic details, treats mood disorders, and displays information and artistic works. After reviewing the myriad applications of light, it is clear that light is foundational to biological flourishing, technological progress, creative expression, and human knowledge. Harnessing properties like illumination, energy, data transmission, and therapeutic effects expands what is achievable across industries and endeavors. From photosynthesizing plants to gazing up at stars to reading words on an electronic screen, light facilitates connections on scales from the microscopic to the cosmic. Whether natural or artificial, light enables life and discovery in a profound way.

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