Objects either emit or reflect light
Some objects emit their own light and some reflect light from other sources
The classification of light energy and sound energy depends on their properties
Light travels in a straight path from its source and does not need matter to be transmitted
Light can be absorbed, reflected or refracted when it hits another medium
How different objects and materials interact with light and sound energy, eg. prisms separate light into colors; voices echo off mountains; sound travels further in water than air
Advancements in light and sound technology help people to remain safe and can improve their quality of life
Devices that make use of properties of light and sound, eg. telescope, microscope, motion detector, street lights, microphone, hearing aid, telephones, light and sound pollution
People measure sound and light intensity
Ways people protect themselves from light and sound hazards, eg. sun protection, headphones and earplugs, reflective material on clothing, bicycle bell, vehicle back up signals, street lights, fire and lightning alarms
The classification of light energy and sound energy depends on their properties
Sound travels in a straight path and needs matter to be transmitted
Sound can be absorbed or reflected and sound can be modified by loudness or pitch
How different objects and materials interact with light and sound energy, eg. prisms separate light into colors; voices echo off mountains; sound travels further in water than air