Characteristics of light
What is light?
a form of wave energy
Who was one of the first scientists to try to measure the speed of light?
Galileo
What do scientists call the waves that can move only through matter?
mechanical waves
What is the highest point of the wave above the rest position called?
The crest
How could you describe the path of light?
generally a straight line
What are two ways that light waves are different from other waves?
They travel through matter and through empty space. They also travel much faster than other waves, such as sound, do.
Who eventually made an accurate measurement of the speed of light?
Albert Michelson
What are longitudinal waves?
waves that move in the same direction as the matter is vibrating
What is the lowest point of the wave below the rest position called?
the trough
What two things about light may change?
its speed and direction
Why do we see lightning before we hear the sound of thunder?
Light travels faster than sound
What are two different ways scientists classify waves?
by whether or not the waves can move through empty space or by the direction in which the waves move
Which waves are longitudinal?
sound waves
What is the distance between two crests or troughs called?
the wavelength
What do we call the colors of visible light arranged in order by their wavelengths?
the visible spectrum
About how long does it take for light from the sun to reach the earth?
About eight minutes
What can light travel through?
matter and empty space
What are transverse waves?
waves that move perpendicular to the way that the matter is moving
What is amplitude?
the height of a wave from its rest position to its crest or trough
What is refraction?
the bending of light as it passes from one medium into another
Are light waves mechanical or electromagnetic?
light is an electromagnetic wave
What can electromagnetic waves travel through?
matter and empty space
Are light waves longitudinal waves or transverse waves?
transverse waves
Name four basic properties of waves.
wavelength, amplitude, frequency, and speed
What are the two ways that light can change its direction?
through refraction and reflection
What is frequency?
the number of waves that pass a certain point in one second
How is speed different from frequency?
Speed is the distance one wave travels in one second. Frequency measures the number of waves that pass a certain point in one second.
Define the rest position of a wave
The imaginary center line of the wave between the crest and the trough
What do all waves have in common?
the same basic properties, or characteristics
What kinds of objects refract light?
transparent objects and translucent objects