Why does light travel in straight lines

Light fills up all of the space before it hits the object, but the whole region between the object and the surface is in shadow. Once light has hit another surface or particles, it is then absorbed, reflected bounces off , scattered bounces off in all directions , refracted direction and speed changes or transmitted passes straight through.

Rainbows and prisms can split white light up into different colours. Experiments can be used to show that each of these colours has a different wavelength. At the beach, the wavelength of water waves might be measured in metres, but the wavelength of light is measured in nanometres — 10 -9 0. In , Albert Einstein proposed that light is made of billions of small packets of energy that we now call photons. These photons have no mass, but each photon has a specific amount of energy that depends on its frequency number of vibrations per second.

Each photon still has a wavelength. Shorter wavelength photons have more energy. The photoelectric effect is when light can cause electrons to jump out of a metal. These experiments confirm that light is made of these massless particles called photons. Newton identified seven colours in the spectrum on his study wall: Physics Narrative A small disagreement about colour Teaching Guidance Misconceptions Light, Sound and Waves Some students may consider light as only a property of large conspicuous luminous objects Number of Resources 2 Number of References 1 Number of Diagnostic Resources 0.

Light, Sound and Waves Some students consider darkness as important a concept as light e. Some students may intuitively link vision with brain activity but some may not Number of Resources 1 Number of References 4 Number of Diagnostic Resources 0. Since the wavelength of light is less than a micron a thousandth of a millimeter , it acts like a ray in the many common situations in which it encounters objects larger than a micron. For example, when light encounters anything we can observe with unaided eyes, such as a mirror, it acts like a ray, with only subtle wave characteristics.

We will concentrate on the ray characteristics in this chapter. Since light moves in straight lines, changing directions when it interacts with materials, it is described by geometry and simple trigonometry. This part of optics, where the ray aspect of light dominates, is therefore called geometric optics. There are two laws that govern how light changes direction when it interacts with matter. These are the law of reflection, for situations in which light bounces off matter, and the law of refraction, for situations in which light passes through matter.

A straight line that originates at some point is called a ray. The part of optics dealing with the ray aspect of light is called geometric optics. Light can travel in three ways from a source to another location: 1 directly from the source through empty space; 2 through various media; 3 after being reflected from a mirror. Refraction is the bending of light it also happens with sound, water and other waves as it passes from one transparent substance into another.

This bending by refraction makes it possible for us to have lenses, magnifying glasses, prisms and rainbows. Begin typing your search term above and press enter to search.

Press ESC to cancel. Skip to content Home Philosophy Why do light travel in a straight line? Ben Davis September 19, Why do light travel in a straight line?