Science C4

Question 1

aperture

Answer 1

the opening in a lens through which light passes to enter the camera; opens to different sizes to allow more or less light to enter the lens.

Question 2

camera eye

Answer 2

The ability to record or recall detailed impressions of what one sees with photographic accuracy.

Question 3

charge-coupled device (CCD)

Answer 3

the sensor used in digital cameras instead of film, used for serious astronomy; an electron device used for data acquisition; composed of many tine pixels, each of which records a buildup of charge to measure the amount of light striking it.

Question 4

ciliary muscle

Answer 4

a ring of smooth muscle in the eye’s middle layer that adjusts the shape of the lens to allow for focusing objects at various distances on the retina

Question 5

compound eye

Answer 5

• mostly in insects; use many small vision units called ommatidium. A tiny lens sits at the outside end of one end, touching a cone that directs light to the receptors within the tube walls.

Question 6

cones

Answer 6

-cones detect colour
-Cones can’t function in low light, so all you can see are shades of grey.
Humans have three types of cones, Birds have five different types of cones
Nocturnal animals have MORE rods than cones in their retinas.
Remember: Rods = light, Cones = colour & detail

Question 7

cornea

Answer 7

the transparent front part of the eye that covers the iris and pupil; helps refract light

Question 8

diaphragm

Answer 8

a device for varying the effective aperture of the lens in a camera or other optical system.

Question 9

far-sightedness

Answer 9

Farsightedness - cannot see close objects clearly

• lens is unable to refract light enough to focus on the retina
• image falls behind the retina
• corrected by converging (convex) lenses

Question 10

film

Answer 10

When light strikes the film, the film changes chemically, forming an image.

Question 11

iris

Answer 11

band of muscle in the eye that controls the size of the pupil and the amount of light entering the eye (similar to the diaphragm of a camera)

Question 12

lens

Answer 12

Lens (eye): a transparent biconvex structure in the eye that helps to refract light to be focused on the retina
Lens (1): a transparent biconvex glass lens that refracts light

Question 13

near-sightedness

Answer 13

Nearsightedness - cannot see distant objects clearly

• lens refracts light too much
• image falls in front of the retina
• corrected by diverging (concave) lenses

Question 14

nocturnal

Answer 14

Nocturnal Animal Eyes - animals are awake at night.
-The eyes of nocturnal vertebrates allow them to collect as much light as possible in 3 main ways:
Pupil size
Tapetum Lucidum
More Rods
Nocturnal animals have MORE rods than cones in their retinas.

Question 15

optic nerve

Answer 15

nerve that leads from the retina to the brain

- the optic nerve connects to the retina; this creates a blind-spot

Question 16

Rods

Answer 16

Rods are highly sensitive to light,
rods are sensitive to even small amounts of light, they can function in very low light.
Rods are far more sensitive to low levels of light than cones.

Question 17

phosphors

Answer 17

The phosphors in night vision googles glow green when the particles strike them. The person wearing the Goggles sees a glowing green image.

Question 18

Rods

Answer 18

Rods are highly sensitive to light,
rods are sensitive to even small amounts of light, they can function in very low light.
Rods are far more sensitive to low levels of light than cones.

Question 19

pixel

Answer 19

When a computer receives an image, it divides the picture up into small elements called pixels. Each pixel is assigned coordinates just like the row and seat numbers for a stadium seat. The resolution of an image refers to the number of pixels per unit area. Pixels are small elements that make up a picture.

Question 20

pupil

Answer 20

opening in the eye that lets in light (dim = large pupils [dilated]; bright = small pupils [constricted])

Question 21

resolution

Answer 21

Resolution: refers to the number of pixels per unit area
Imagine, two images are the same size
The one with more pixels will look best
More pixels = smaller sized pixels = Better Quality
= high resolution

Less pixels = larger sized pixels = Poorer Quality
= low resolution

Question 22

retina

Answer 22

special lining on the back of the eye; when light hits the retina, receptor cells send messages to the brain, which translates them into an image

• rods - very sensitive to light; used in low-light conditions
• cones - can distinguish color; cannot be used in low-light conditions

Question 23

shutter

Answer 23

lies behind the aperture. The shutter acts like a set of doors that open when you press the button to take a picture. The longer the shutter remains open, the more light enters the camera and strikes the film or sensor (CCD).

Question 24

tapetum lucidum

Answer 24

(nocturnal animals) They also have a layer inside their eyes called the tapetum lucidum, which acts as a mirror to reflect light inside their eye.
is a layer of tissue in the eye of many vertebrates. Lying immediately behind the retina, it is a retroreflector.

Question 25

Compare structures in the eye with the comparable camera structure.

Answer 25

Lens Lenses In camera, the lens moves closer/further from the film to focus. In your eyes, the lens changes shape to focus. Pupil Aperture Tiny muscles in the iris change the size of the pupil like the aperture of a camera to control the amount of light getting into the eye. The aperture is the hole. Iris Diaphragm The iris controls the size of the pupil and allows in certain amounts of light. The diaphragm is what controls the aperture size. Retina Film -When light strikes the film, the film changes chemically, forming an image. -When light hits the retina, receptor cells send messages to the brain, which translates them into an image Eyelid Shutter The shutter acts like a set of doors that open when you press the button to take a picture. The longer the shutter remains open, the more light enters the camera and strikes the film or sensor An eyelid is a thin fold of skin that covers and protects an eye.

Question 26

What are rods and cones and what are their similarities and differences?

Answer 26

Rods are highly sensitive to light, rods are sensitive to even small amounts of light, they can function in very low light. Rods are far more sensitive to low levels of light than cones. -cones detect colour -Cones can’t function in low light, so all you can see are shades of grey. Humans have three types of cones, Birds have five different types of cones Nocturnal animals have MORE rods than cones in their retinas. Remember: Rods = light, Cones = colour & detail Simular: -Rods and Cones are the photoreceptors of an eye. - Both absorb light (photon) at a different wavelength. - These are modified nerve cells. - The process of phototransduction is same in both the cells.

Question 27

Know the differences between near and far-sightedness and the types of lens required to correct each.

Answer 27

``` near = can't see things from far away, lens: concave far = can't see things close up, lens: convex ```

Question 28

Be able to describe how night vision goggles work and what type of particles are involved.

Answer 28

In night vision goggles, light is focussed onto an image intensifier. Inside the intensifier, the light energy releases a stream of particles. These particles then hit a phosphor coated screen. The phosphors glow green when the particles strike them. The person wearing the Goggles sees a glowing green image.

Question 29

In a digital image what is the photo image converted into?

Answer 29

pixels

Question 30

What are the advantages of digital imaging?

Answer 30

The advantage of digital imaging is how quickly it can be moved from location to location. When you digitize images the image is sent through the camera which will turn it into digits, so when you reopen the image it will still be there whether it's on a computer or camera. Another advantage of digital imaging is that digital cameras can be created to collect different parts of the electromagnetic spectrum.

Question 31

How are compound eyes different than camera eyes?

Answer 31

Camera Eyes vs COMPOUND EYES Are often found in insects Each eye is made up of many smaller units. Each individual unit is called an ommatidium

Question 32

Describe how fish/bird/cat/owl eyes are different than human eyes?

Answer 32

The insect compound eye is like having lots of little eyes looking in different directions, but each little eye doesn't see very well. The human eye can swivel, but it only looks in one direction at any given moment.