• Why is the sky blue?
  Sunlight is white - which means it contains all the colors of the ...

• What is an incident ray?
  When scientists talk about reflections, they distinguish between the ...

• How is energy conserved?
  Energy can be neither created nor destroyed. When energy is converted ...

• Why can’t you see ultraviolet?
  Ultraviolet light is light with wavelengths too short for the human ...

• What is energy efficiency?
  Some machines waste a great deal of energy, while others waste very ...

• How does a prism split colors?
  Prisms split white light into separate colors by refracting (bending) ...

• How are energy and mass linked?
  Energy is a form of mass; mass is a form of energy. In nuclear ...

• What is infrared?
  Infrared is light with wavelengths too long for the human eye to ...

• What’s absolute zero?
  Absolute zero is the coldest possible temperature, the temperature at ...

• Who wrote in pictures?
  Mayan and Aztec scribes. The Mayans invented the first writing in ...