The Eye

The Eye

The Basic Structure
1. Cornea
  1. Transparent 'window' with a convex shape, and a high refractive index - cornea does most of the eyes focusing
2. Iris
  1. Coloured part of the eye
  2. Made of muscles that control the size of the pupil - the hole in the middle of the iris
    1. This controls the intensity of light entering the eye
3. Lens
  1. Change shape to focus light from objects at varying distances
    1. Connected to ciliary muscles by suspensory ligaments and when the muscles contract, tension is released and lens takes on a fat, spherical shape
      1. When they relax, the suspensory ligaments pull the lens into a thinner, flatter shape
4. Retina
  1. Images are formed on the retina - covered in light-sensitive cells
    1. These cells detect light and send signals to the brain to be interpreted
The eye can focus on objects between the near and far points
1. The far point is the furthest distance that the eye can focus comfortably
  1. Infinity for normal-sighted people
2. The near point is the closest distance that they eye can focus on
  1. 25cm for adults
3. As the eye focuses on closer objects, its power increases - the lens changes shape and the focal length increases
  1. Distance between lens and image stays the same
A camera forms images in a similar way to the eye
1. When you take a photo of a flower, light from the object travels to the camera and is refracted by the lens, forming an image on the film
2. 1 - The image on the film is a real image, because light rays actually meet there
3. 2 - The image is smaller than the object, because the object's a lot further away than the focal length of the lens
  1. Image is inverted
4. 3 - The same thing happens in our eye - a real, inverted image forms on the retina
  1. Our very clever brains flip the image so we see it the right way up
5. 4 - The film in a camera or the CCD in a digital camera, are the equivalent of the retina in the eye - they all detect the light focused on them and record it

Nächster

Beschreibung

Zusammenfassung der Ressource

Medienanhänge

ähnlicher Inhalt

	Erstellt von jadepalmer98 vor mehr als 12 Jahre