Waves

Waves

1. Reflection and Refraction

   • Reflection: The wave can bounce back, eg light on a mirror
   • Refraction: The wave can change speed and direction, eg light travelling from air into water.
   • Absorption: The waves can give up its energy, eg microwaves are absorbed by food.
   • Angle of incidence = Angle of reflection

2. Radiowaves

   • Communication
   • Can travel long distances
   • Not strongly absorbed by the atmosphere
   • Not harmful

3. Microwaves

   • Microwaves are not absorbed my dry objects, eg glass and ceramaics
   • Used to cook food
   • Short radiowaves

4. Infared

   • Cannot be seen by the human eye
   • They can be sensed by skin from the warmth
   • Police use infrared camera to track criminals at night