Science p.1

• What is the speed of light?

  300,000 km/s
• what is reflection?


  it is when light bounces off an object
• What is refraction?


  bending of a light ray
• Why does refraction occur?


  when light travels from one medium to another
• From a less dense medium to a more dense medium...


  light bends towards the normal
• From a more dense medium to a less dense medium...


  light bends away from the normal
• 3 characteristics of refraction from a plane mirror


  1. virtual image

  2. image is upright

  3. image is same size
• What is dispersion?


  when a prism is used to seperate white light into a spectrum
• what makes magenta?


  red and blue
• what makes cyan?


  green and blue
• what makes yellow?


  green and red
• why is an apple red?

  the apple absorbs all the other colors and reflects red to your eyes.
• why is an object black?


  because all colours are absorbed.
• whys an object white?


  because all colours are reflected.
• what are 3 characteristics of diffuse reflection?


  1. happens from a rough surface

  2. no image is formed

  3. angles are unequal
• what are 3 characteristics of specular reflection?

  1. happens from a smooth surface

  2. a clear image is formed

  3. the angles are equal
• function of cornea


  Refracts light into the eye
• function of the pupil

  allows light to enter the eye
• function of the iris

  Controls the amount of light entering the eye
• function of the retina


  turns light into electrical signals
• function of optic nerve


  carries impulses to the brain
• function of lens


  Focuses light onto retina
• function of ciliary muscle


  Changes the shape of the lens
• function of vitreous humor

  maintains the shape of the eye
• what is the reaction taken in a retina called

  photoreceptor
• What does the lens do?

  concentrates light rays when they pass through by refraction
• How does the eye work?

  1. light enters the eye through the cornea

  2. the pupil adjusts in response to the light

  3. the lens focuses light onto retina

  4. optic nerve transmits visual info to the brain
• how does a camera work


  The lens takes all the light rays and uses glass to redirect them to a single point, creating a sharp image
• Name the parts of a camera

  CCD, aperture, lens, sensor, shutter
• Carbohydrates function & food source


  provide energy e.g. pasta, potato
• Protein function & food source


  growth and repair e.g. meat, fish
• Fibre function & food sources


  for health & constipation e.g. celery, cereal
• Lipids function & food source


  Store energy e.g. red meat, butter
• What are nutrients?


  important substances to keep our body healthy
• How do you test for starch?


  Add a few drops of iodine solution to the food solution. If starch is present it will turn from an orange to a 'blue-black' colour.
• How do you test for lipids?


  Add a few drops of ethanol to the food solution. Shake, leave for 1 minute and pour the ethanol into a test tube of water. If lipids are present it will turn from a clear to cloudy substance.
• How do you test for sugar?


  Add a few drops of benedict solution to food solution. Heat in water bath, if sugar is present, it will turn from blue to an orange color.
• How do you test for proteins?


  Add 10 drops of biuret solution to the food solution. If protein is present it will turn from a blue to a purple solution.
• What is malnourishment?


  a deficiency to not have enough of something
• Problems of being underweight


  Poor immune system, lack of energy