Humans have been fascinated by light. Light is everywhere around us and important to both plants and humans. The light we see on Earth is natural light and a form of energy from the sun. It takes just over 8 minutes for light to reach Earth. If your child shows interest in science, natural phenomenon, they may want to learn about light and its source. How about you teach them about light in a simple yet interesting way. Here we bring you some interesting information and facts about light that you can tell your kids.
What Is Light?
Light, as we see it on Earth, is a form of energy waves emitted by the sun. The sun produces a huge range of electromagnetic radiation, and the energy that reaches the Earth arrives as solar radiation. To the human eye, each wavelength appears as a separate colour. The seven colours of a rainbow actually cover the entire spectrum of visible light.
The wavelengths other than red, orange, yellow, green, blue, indigo and violet can be seen only through special cameras or instruments. Wavelengths below red are known as infrared, and higher than violet is called ultraviolet that cannot be seen by the human eye. Our eyes receive the light, and our brain translates it into the colour spectrum. Light exists in tiny packets called photons and shows the properties of both waves and particles, like a particle, light moves in a straight line. When its path is blocked by an object, it creates shadows. Light arrives on our planet from the sun. The speed of light depends on the medium it is travelling in. Light travels the fastest when in a vacuum, and the speed drops as the density of the medium increase. Light is identified with life. It facilitates food chains both on land and in the sea. It acts as a key stimulant during photosynthesis in plants and provides nourishment for the survival of plankton in the oceans. These two forms of herbal life become an important source of food for many species, including human beings. And it is one of the reasons why ancient civilisations worshipped the sun as the giver of light/life.
Who Invented the First Electric Light?
Humphry Davy invented an electric battery after experimenting with electricity to make the first electric light in 1802. After connecting the wires to the battery and a piece of carbon, the carbon glowed, emanating light. This invention was known as the Electric Arc lamp.
Sources of Light
There are numerous sources of light that can be divided as per their categories:
- Natural light – Its sources are the sun, moon, and stars
- Artificial Light – Its sources are bulbs, tube lights, etc.
- Luminescence Light – Its sources include neon light, fluorescent light, bioluminescence light, an incandescent light source, fire.
Uses of Light
- Light is used to make food
- It is used for drying and evaporation
- It is used for heat and temperature
- Light is used for regulation of physiology
What Are Northern Lights?
The Northern lights or aurora borealis, appear in many forms like patches or scattered clouds of light to streamers, rippling curtains to arcs or shooting rays that light up the night sky as a dazzling natural phenomenon. This ethereal display happens due to the interaction between Earth’s magnetic field and charged particles emitted by the sun. As the solar wind approaches the Earth, its charged particles or ions collide with the air molecules in the Earth’s magnetic field, causing the molecule atoms to become excited. The energy released during these collisions causes a colourful glowing halo around the poles, commonly known as the aurora. As electrically charged particles enter the Earth’s upper atmosphere at high speed, the lights of the aurora can extend from 80 kilometres to as high as 640 kilometres above the earth’s surface. The best places in the world to see the Northern lights are mostly closer to the Arctic Circle, including Iceland, Alaska, Canada, Norway, Greenland, Finland, and Sweden. The Northern Lights itself is not harmful to humans, but the electrically charged particles produced by it could have some potentially negative impact on technology and infrastructure.
Other Interesting Information About Light for Children
- The sun is the main source of natural light.
- White light can be broken down to give a range of colours like blue, red, green, orange, yellow, violet and indigo.
- Sir Isaac Newton saw a rainbow of colours when sunlight passed through a glass prism. He also noticed that the light was bent and split into seven colours called the light spectrum.
- A magnifying glass refracts light giving an enlarged view of an object.
- Forensic scientists use UV light to show footprints, fingerprints, and blood traces that cannot be seen with the naked eye.
- Light is the only form of energy that humans can actually see with their naked eyes.
- The laser is a manmade light that is used to cut all kinds of metal and materials. They can make accurate cuts through think layers of cloth.
- One can see light before the occurrence of thunder as light travels faster than sound.
- Plants convert light energy from the sun into food by the process called photosynthesis.
- Light waves vary in sizes. The distance between two wave peaks is known as wavelength.
- A coloured object reflects only certain wavelengths of light. The reflected light is the colour the object appears to be. So a red apple reflects the red light after absorbing the rest of the colours of the light.
- Some animals and insects can see parts of the spectrum (ultraviolet light) that humans cannot see.
- There is no light in space as there is no object that can bounce back the light. We can see the moon because it reflects the light of the sun.
- Laser lights are used in medical surgeries, television, CD and DVD players, and bar code readers at the store and telephone signals that carry laser light over special cables.
- A mirror has a smooth surface. When it reflects a ray of light, the angle of incidence is always equal to the angle of reflection. Therefore rough surfaces do not produce clear images.
For centuries, light has been a tremendous subject that has transcended all boundaries, including geographic, age, culture, and more. The study of light is known as optics, which, along with photonics, is an important area of research in modern physics. We hope the information covered in this article will help you teach your child about light and stimulate their curiosity to search more and learn more about this topic.