GHSGT Review

Day 2 –

Describe the Properties of a Wave

What is a wave?

Echos and Reflections

Sound waves that are reflected can cause an echo.

Mirrors can reflect light waves to give us reflected images.

Properties of a wave

Wavelength – the length of a wave from peak to peakFrequency – the number of wave peaks that occur in a unit of time (measured in hertz, Hz)

As the wavelength increases the frequency decreases.

What do you know about light?

Electromagnetic spectrum – made up of visible and invisible

waves of transverse energy waves, ranging from low frequency to very high

frequency, which can travel at the speed of light in a vacuum.

Light waves are part of the electromagnetic spectrum. The frequency of a light wave determines its color.

Why is a sunset more red?

We could use mirrors to manipulate light waves…

• A flat mirror is a smooth shiny surface that reflects light. Light travels in a straight line as it is reflected from a surface. – The incident ray is the light ray that strikes

the surface. – The reflection ray is the light ray that reflects

off the surface. – The Law of Reflection states that the angle

of reflection equals the angle of incidence.

REFLECTIONBouncing a ray or wave off a surface

REFRACTIONis the bending of a wave or light by the

change in density of the medium

Using lenses to bend light

 Images in convex Images in concave mirrors are always                       mirrors are always smaller.                                          bigger.

Just a few more terms to review…

• Interference - the superposition of two or more waves resulting in a new wave pattern

•Diffraction - the bending and spreading of waves when they meet an obstruction.

Special things to know about sound…

• cannot travel through empty space or a vacuum.

• Sound travels faster through solids than through liquids or gases.

• When temperature increases, the speed of sound increases.

• When the air becomes more humid, the speed of sound increases.