Light Facts

We see light from the sun every day.

Light is measured in ‘waves’ and the light that we can see is only a small portion of the types of light.

They are measured in the ‘electromagnetic spectrum’.

The human eye sees specific areas of the spectrum, but other animals and insects can actually see parts of the spectrum that we can’t.

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Light Facts for Kids

  • People need light so we can see
  • Light is a beam of energy that travels in a wave.
  • Plants turn light energy from the Sun into food. This is called photosynthesis.
  • Light travels at 300,000 km/second
  • It takes 8 minutes and 20 seconds for light from the Sun to reach Earth
  • White light a mixture of all colors red, orange, yellow, green, blue, indigo, and violet.

Light is an energy

Light is an energy beam that moves in wavelengths.

It is made up of tiny photons, each contains a lot of energy.

The strength of the light depends upon the amount of energy each photon contains.

How fast is light?

Light doesn’t travel as fast when it has to pass through mediums that are different, such as air, water or glass.

These mediums cause the light to ‘refract’ and that slows the light down.

The refractive index of glass is 1.5, slowing the speed of light down to 200,000 km per second (124,000 miles per second).

Water has a refractive index of 1.3 and the refractive index of air is 1.0003. Air slows light down only a small amount.

Can you control Light?

Light can be controlled and produced in so many ways.

A camera can control the amount of light that comes into the camera lens.

We also use light in televisions, medical systems, copy machines, telescopes, and satellites.

Light gives life

Light is used by plants to convert the light into energy as their ‘food’.

The process is called ‘photosynthesis’ and converts carbon dioxide through the energy of the light.

Light from the Sun

Light from the Sun contains red, orange, yellow, green, and blue light rays and many different shades of each of these colors. But, this also depends on the energy and wavelength of the rays (also known as electromagnetic radiation).

If a light ray has a long wavelength, it has less energy, and likewise, a short wavelength can produce more energy.

What did Isaac Newton find out?

Isaac Newton

Isaac Newton studied light as it hit a glass prism.

When he saw the light expand into the different colors (ROYGBIV or Roy G. Biv):

  • Red
  • Orange
  • Yellow
  • Green
  • Blue
  • Indigo
  • Violet

He realized that light refracts and each color traveled through glass (or other materials) at varying speeds.

We can see the same thing happen when we see light through a prism or even when we see a rainbow.

Each color within light has a different wavelength.

Each type of light has a varying length of ‘wave’.

Some animals can see ultraviolet light (UV) but the wavelength is not available for the human eye to see.

Scientists have developed technology so that we can view UV light.

Who was Galileo Galilei

Galileo Galilei

Galileo Galilei was an Italian scientist that developed a number of scientific discoveries.

One of them was the creation of a telescope that was thirty times the magnification of other telescopes.

He used his telescope to look at many of the planets and discovered four of the largest moons that were orbiting around Jupiter.

These four moons were called ‘Galilean satellites’.

Who invented the light bulb?

Thomas Edison

An American called Thomas Edison is credited with inventing the lightbulb in 1879. However, Humphry Davy invented the first electric light in 1802. But Edison was the first to file a patent for his design.

Over the years, the lightbulb has evolved from the frosted lightbulb, power beam bulbs for car headlamps, neon lighting, halogen light bulb, Long life bulbs, and LED lightbulbs

Northern Lights

The Northern Lights, also known as the Aurora borealis, can be seen in the northern hemisphere. It is a naturally occurring phenomenon that depends on the solar activity on the Sun.

There is no particular time of year that is ideal to see the northern lights. Aurora’s can occur throughout the year, but generally, the summer months make them more visible to the human eye.

This Sun goes through a solar cycle every 11 years. Therefore there is more activity towards the end of this solar cycle when the last solar maximum occurring in June 2014.

Other Facts

  • A light wave is made up of energy in the form of magnetic and electric fields. These fields have a right angle vibration to the wave direction of movement and at right angles to each other.
  • Light will travel in a completely straight line until it hits an object that will bend it. The light that is in a straight line are called ‘light waves’.
  • The study of the behavior and properties of light is known as ‘optics’. This is a scientific branch of physics.
  • Light travels in a vacuum at 300,000 km per second (186,000 miles per second).
  • Space does not have any light. We can see things in space due to light bouncing off of the objects in space.
  • Infrared light has a wavelength that is too long for the human eye as well.
  • The speed of light is incredible. For light to get from the earth to the moon it takes only 1.255 seconds.
  • Light that we see from the sun actually left the sun ten minutes before we see it.
  • Sunlight is pretty powerful. Light from the sun can reach 262 feet (80 meters) in the ocean.