12 Uses of Light in Our life| Its Importance and significance

Light is a valuable resource present.

It is one of the most exciting things which has been surprising the scientists for long.

Even famous scientists like Albert Einstein and Newton were fascinated by the light so much.

Hence, Einstein proposed E=MC², and also studied the photon and wave nature of light to a large extent.

But many of us are not aware of it due to lack of direct knowledge about its use.

Of all the sources of light, sunlight is the most common so, we will discuss the uses of light in life from all the sources.

Uses of Light in Our life:

The significance of light kill in

1. Food: Photosynthesis is a concept in biology wherein food is synthesized by use of light. Light is the sole source of food generation for all living organisms on the earth. Except for a few chemotrophic bacteria? Almost all living beings depend on light for their food and energy.

Plants and other autotrophs synthesize their own food materials by use of light. The light which falls on the leaves and other greenish surfaces on plants are trapped. This trapped energy is converted to reserve energy in the form of food by a process known as photosynthesis. Here the light energy is used to synthesize carbohydrates. The autotrophs like plants use carbon-dioxide and water {CO2 +H2O= C6H12O6} to form carbohydrates in the presence of sunlight.

From these plants, animals get the required food materials and thereby needed energy for living.

These carbohydrates inside the body, break down and convert back into carbon dioxide and water releasing the energy from within after digestion.

So plants depend on sunlight for their food and animals depend on plants. Thus all the living beings are dependent on light for food.

This phenomenon is present both on the earth surface and also the marine environments.

Energy for bio-molecules synthesis: After food (carbohydrates) is consumed, it is broken down into energy. This energy is produced in the form of ATP (adenosine triphosphate). This ATP breaks down to ADP and AMP to release energy in cells and tissues.

This ATP is to build up the body proteins and maintenance of physiology. The cell and nucleus transcription mechanism uses this energy to form messenger RNA (m-RNA).

This m-RNA in the presence ATP again translates to produce desired hormones, enzymes, proteins and fats required for the body. Thus the light energy conserved in the food is used up to build and maintain the body.

2. For Vitamin D synthesis: Vitamin-D is a type of vitamin which is needed to be supplied from the external source. This is because it can be synthesized from ergosterol and cholesterol by irradiation with sunlight.

When the light fall on the skin, the ergosterol below the skin converts to vitamin-D. So if someone stays away from sunlight for long, he tends to develop the vitamin-D deficiency. Also to get a regular dose of vitamin D, it is important to expose to sunlight everyday. The best time would be in the mornings and evenings (before dawn).

3. Vision: All animals, birds are able to see the objects around them due to presence of eyes. But without light, these eyes might be of no use. Because of light, the eyes can receive the image of the objects and send the information to the brain. From this visual information we comprehend the objects. Hence we can notice that in darkness we could see nothing. So light makes us able to see objects around.

4. Colors: This whole world looks beautiful due to colors. But in darkness we see no colors. This is because all the colors in this world are possible only due to light. The light has many spectra. Each spectra has a color and these are broadly referred as VIBGYOR. In full form it is








All these color have different wavelengths and frequency. And when light falls on an object, it absorbs some spectra and reflects others. The reflected light falls on to our eyeball and passes the impression to brain making it look colorful. So it is the ability of the object to absorb some spectra of light and reflect the remaining makes it look colorful. We would not be able to see the color if the light is absent or our eyes are not functional.

5. Maintenance of temperature: Light is a form of energy. And sunlight has huge energy by which the temperature on the earth is maintained. Due to this, the life exists on the earth.

If you think why? Just imaged those areas of the earth without proper light in the whole year. Those areas are icy and even have heavy snowfall. If the sunlight is absent, the temperature of the earth can drop drastically such that the whole water on the earth gets frozen. If this happens, the animals especially homeotherms die instantly due to low temperatures. Even the poikilothermic animals may find it difficult to survive. So light is essential to maintain temperature on the earth and thereby life.

6. Maintains Body clock or circadian rhythm: Everyday light keeps plants and animals ticking with time.

There is a clock inside both plants and animals which keep them active during the day and relaxed at night. This clock is controlled by light.

Plants broaden their leaves during daytime starting from sunrise till sunset. Even we can notice leaves and few flowers like sunflower which bent towards light through the day.

Uses of Light

Also, the plants grow in the direction of light as auxin a plant growth hormone is regulated by light.

Birds, insects and other animals are also controlled by light. We can notice birds stop making noise at evening and start making noise early in the morning. This habit is controlled by light as it can tick their body clock. Even if we do not have a watch, the sunlight changes can make you fall asleep or rise regularly.

7. Drying and evaporation: Sunlight helps in the drying of the soil, forests, air and rocky surfaces due to its ability to heat up. Also, it helps water evaporate from oceans and water ponds. This drying is helpful in two ways to live on earth like

a) Water cycle: The water cycle is a way by which fresh water on the earth surface is kept recycled for drinking and irrigation. The water from land evaporates to form clouds. These clouds again cause rainfall to return the fresh water to the earth surface. So due to rains, there is fresh water to drink and also use for irrigation. Without water cycle, all the water on the earth would remain in the ocean so that no water is available to drink.

Or, the water on the earth surface would be so filthy such that it is unfit for drinking. So sunlight contributes to the water cycle and thereby maintains rainfall and water for human use.

b) Scavenging: Sunlight helps in keeping the nature clean. Due to drying, there is no growth of weeds, algae and other microbes keeping the environment clean and tidy. Even dead bodies and other waste material get dried and lose their mass and get degraded fast.

8. Sterilization: Light especially its ultraviolet component is an excellent sterilizing agent. Haven’t you noticed in a supermarket or hospital the use of UV lamps? These UV lamps are good sterilizers. The UV rays kill the microbes in the air keeping the area sterile. So UV light is classified under the dry method of sterilization.

Sunlight is an effective sterilizing agent. When blankets and other hospital mattress are dried in sunlight, all the microbes get killed.

9. Solar energy: Light from the sun helps to generate green energy or renewable energy.

Solar panels imbibe sun rays and convert it into electric energy which can be used for domestic needs.

Now we began to realize the importance of solar energy. It is one of the alternative energy or renewable energy which is safe for the environment. It generates no pollution and other harmful wastes.

Other means of energy generation by use of coal and atomic energy is responsible for global warming.

So if we shift towards this form of energy, we will be saving the environment.

10. Spectroscopy: Light is used for analysis of compounds by spectrophotometry. This spectroscopy can be used for both qualitative and quantitative analysis. There are many forms of spectroscopy which vary based on the spectra and wavelength of light used.

Some of them include colorimetry, atomic absorption spectroscopy. This spectroscopy is further extended to be combined with other analytical techniques like chromatography.

11. Light and plant development: Plants grow towards the sky as they are guided by light. The plant growth hormone namely Auxin is responsible for it. The hormone is present in the apical parts (tips) of growing regions. Based on the availability of light, it directs the growth. That is the plant grows towards the light. So you can notice some plants taking different turns when they are in between the other plants to reach the sunlight. But why plants need light? Because they need light to synthesize their own food.

12. Signal system: Light is the crucial visible signals. We use light as traffic signals, navigation signals, etc.

Even our TV remote use infrared light rays to give the signal to Television.

Thus light which appears to be a simple phenomenon of the universe has divers use to humans and life on earth.

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