What is Light?
Light is made of electric and magnetic energy. This energy travels as a wave with both frequency and amplitude. The waves vibrate in the direction perpendicular to that of the motion. These are called transverse waves.
Unlike sound, light can travel without a median. It does not depend on compressions and rarefactions.
The wavelength of light is the distance between two peaks. If you multiply the wavelength by the frequency, you get the speed of the wave.
Light is measured in Joules.
Light is also a particle as well as a wave. How can it be both? Scientists did experiments that showed it had particles of both. They concluded that it was a particle and a wave.
Particles of Light
The particles of light are called photons. A photon is a bundle of energy through which light travels. Photons also have frequency. If a photon has a higher frequency, it has more energy. However, photons usually have very little energy.
Types of Objects that react to Light
When light hits an object, photons bounce back. This is called scattering light. Sometimes a photon is absorbed in an object. The object gains energy, which is usually converted to thermal energy. Darker objects absorb more photons.
It is also possible that light can pass through objects.
How Light Pass objects
- Lets most light pass
- Light blurs when passes through
- No light passes through
How do shadows form?
When an opaque object is between light and another object, the light does not pass through the opaque object, and leaves a certain spot of the other object dark.
How angles affect the Shadow
If the sun is low, a smaller angle is formed. It takes longer for the light to reach the ground. A longer shadow is made. As the angle becomes bigger, the shadow becomes shorter.
How does light Bounce off Mirrors?
Light bounces off mirrors like sound bounces off a cliff. There are two types of mirrors: flat mirrors and curved mirrors.
- The light bounces off of the object without changing the appearance of the object
- There are two types of curved mirrors
- Concave Mirrors
- Curved inwards
- All light is focused on a main point
- Convex Mirrors
- Curved outwards
- All light is spread out
- Concave Mirrors
How does Light Refract off lenses?
Refraction is the bending of waves as it goes through an object.
Lenses let light go through them with different angles. There are three types of lenses: flat concave and convex
Flat Lenses let light go through them without changing the image.
Concave Lenses work like convex mirror; they make things look smaller.
Convex Lenses work like concave mirrors; they make things look bigger.
Why do we see colors?
Our eye sees light with different wavelengths, which is because they are different colors. Light with longer wavelengths look red. Light with smaller wavelengths look purple.
What is a Spectrum?
A spectrum is a band of colors that we see that is from light passing through a prism.
A prism is a piece of clear glass in a form of a geometric shape.
Why are opaque and translucent objects colored?
An opaque object is the same color that scatters off it or gets absorbed into it. A translucent object is also the same color as the light that passes through or gets absorbed.
Light that is not visible
Light travels in electromagnetic radiation. There are forms of light with large wavelengths like radio waves and infrared rays, and also light with smaller wavelengths like ultra violet rays, X rays, and gamma rays. None of the forms of electromagnetic radiation that was stated can be seen by the naked eye. All these forms travel at the speed of light and can move through a vacuum. The sun can produce all the forms of electromagnetic radiation.