Wave Behaviour Vocabulary

Words That Describe Waves

Waves have special words that help scientists talk about them. Here are some you can use too.

Amplitude is how tall a wave is, measured from the middle to the top of a crest. For a sound wave, a bigger amplitude means a louder sound. A whisper has a small amplitude, and a shout has a big one.

Frequency is how many wave cycles pass by each second. A sound wave with a high frequency sounds high pitched, like a bird tweet. A low frequency sounds deep, like a big drum.

Wavelength is the distance from the top of one wave to the top of the next wave. Long wavelengths and short wavelengths behave differently when they meet materials.

When a wave loses some of its energy as it travels, its amplitude gets smaller over time. Scientists call this damping. It is why a sound gets quieter as it moves farther away from you.

Words About Light and Spectra

Light can be split up and soaked up, and there are science words for each of these things.

A spectrum is the range of colors or wavelengths that light is made of. When white light splits into a rainbow, you are seeing its spectrum.

A continuous spectrum has every color blended smoothly together, with no gaps. Sunlight gives us a continuous spectrum.

An absorption spectrum is a spectrum with dark lines in it. Those dark lines show the exact colors that a material absorbed, or soaked up, on the way to your eyes.

Dispersion is what happens when white light bends by different amounts for each color. Each wavelength bends a little differently, so the colors spread out. This is why a prism can turn a beam of white light into a rainbow. Refraction is the bending itself, and dispersion is the spreading of colors that the bending causes.

How Fast Sound Travels

Have you ever watched a firework explode far away? You see the flash of light first, and then you hear the boom a moment later. That is because light travels much faster than sound. Sound moves through the air at about 343 meters every second, while light is almost a million times faster.

Sound travels as a wave, and like all waves it has a frequency and a wavelength. The frequency tells you the pitch of the sound, and together with the wavelength it sets how fast the wave moves through the air.

Sound needs something to travel through, like air, water, or a solid wall. It moves faster through water than through air, and faster still through solids. That is why you can hear a train coming if you put your ear near the metal rail before you hear it through the air.

When sound waves hit a hard surface like a cliff or a wall, they bounce back. That bouncing is called reflection, and the sound that returns to your ears is an echo.

How Sound Waves Become Sound

Sound travels through the air as a wave, and your ears are built to catch those waves.

Two wave words matter a lot for hearing. The first is amplitude, which is the size of the wave. A sound wave with a large amplitude carries more energy, and your brain hears it as a louder sound. A small amplitude sounds quiet.

The second word is frequency, which is how many wave cycles arrive each second. Your brain hears frequency as pitch. A high frequency wave sounds like a whistle or a bird song. A low frequency wave sounds like a tuba or thunder.

Your outer ear funnels sound waves inside, where they make a tiny flap of skin called the eardrum vibrate. Those vibrations pass through tiny bones and into a spiral shaped part of the inner ear filled with fluid. The moving fluid bends little hair cells, and they send signals to your brain. Your brain then tells you what you are hearing, how loud it is, and whether the pitch is high or low.

Light Behaves Like a Wave

Light is a kind of energy that travels as a wave. It zooms through empty space incredibly fast, at about 300 million meters every second. Nothing in the universe travels faster.

Because light is a wave, we can describe it with wave words. The wavelength is the distance from one wave crest to the next. The frequency is how many wave cycles pass by each second. These two are connected: light with a short wavelength has a high frequency, and light with a long wavelength has a low frequency.

Different wavelengths of light look like different colors to our eyes. Red light has a longer wavelength, and violet light has a shorter one. Together, all the colors make up the visible spectrum.

There are also many kinds of light our eyes cannot see, like radio waves with very long wavelengths and X-rays with very short ones. All of them are the same kind of wave, just with different wavelengths and frequencies.