Light & sound

light

• travels in straight lines and travels around 300,000 kms per second

• faster than sound

luminous

an object that produces light

non-luminous

an object that reflects light

shadows

places where light is blocked

rainbow

white light is not a single colour; it is made up of a mixture of the seven colours of the ____.

filters

can be used to “block” out different colours of light

refraction

• the bending of light rays as they pass between two different media.

• occurs due to changes in the speed of light in different mediums

• different media slow down light by different amounts.

dispersion

this is the refraction of white light into seperate wavelengths (colours)

sound

• produced by vibration

• help us communicate, receive information, and entertainment.

• it requires a medium to travel from one place to another (solid, liquid, gas)

longitudinal

sound produces _____ waves (particles move along the direction of waves)

20Hz to 2000Hz

human can hear sound between ______

ultrasonic

Are considered sound waves with frequency more than 2000Hz

infrasonic

are considered sound waves with the frequency less than 20Hz

doppler effect

is the change in the frequency of sound waves due to relative motion of source and observer.