Week 5

• Natural light


  Light that comes from nature, examples: sun, moon, stars, lightning
• Artificial light


  Any light source that is made from human, examples: LED bulbs, flashlights, candles, lamps, fire
• Light is needed by all living things including humans, animals, and plants. It is used to make plant food, warm bodies, and for survival in humans and animals, as well as for recreation, energy at home and in workplaces, and to help us restore energy that will sustain humans and animals alike.
• Light


  Energy that functions as both a wave and particles, and moves in a straight line
• Classification of light


  • Transparent: able to see objects inside a container because it allows light to pass through it

  Opaque: does not allow light to pass through, examples: bricks, wood, stone, metal

  Translucent: cloudy and allows part of the light to pass through, examples: frosted glass, wax paper, sunglasses, tinted window car
• Shadow


  The dark form created when certain objects block the light
• Clear and dark shadows are created by opaque objects. The shadows are continually changing during the day - they are the longest in the early morning and late afternoon, and tiny or small at noon when the sun is directly overhead.
• The sun is the main source of energy on our planet. Our living things depend on the sun's heat and light.
• Beneficial effects of the sun's heat and light


  • Warms the earth allowing plants, animals, and humans to survive

  Dries laundry, fish, and crops

  Allows for recreational activities
• Harmful effects of the sun's heat and light

  • Sunburn or excessive heat exposure can irritate the skin

  Dehydration or too much perspiration

  Heat stroke

  Drought

  Temporary blindness from looking directly at the sun
• Light


  Moves in a straight line from the source, since it reaches our eyes we can see the object
• 
  

  Tissue paper - is translucent, allowing some light to pass through
• Shadow


  Created when an object blocks out light. At noon, shadows are shortest, and at the start and end of the day they are longest.
• Wood and cardboard - are opaque, they do not allow light to pass through
• Glass - is transparent, it lets light pass through