LAB TEST NOTES and the EYE

Question 1

What is the eye?

Answer 1

The eye is the receptor organ for visible light waves.

Question 2

Describe the process that occurs in the eye.

Answer 2

Eye receives a stimulus - Light
Eye transforms light into nerve impulse
Nerve impulse is carried by the optic nerve and cranial nerves
Light enters the place in the brain responsible for visual processing

Question 3

What is the sclera?

Answer 3

The external membrane of the eye, white of the eye
Helps the eye hold its shape.
Acts as protection

Question 4

What is the cornea?

Answer 4

Transparent layer.
Lets light through.
Bulges out of the front of the eye.

Question 5

What is the choroid?

Answer 5

Dark brown
Many layers of blood vessels
Supplies the eye with blood, oxygen, and nutrients

Question 6

What is the iris?

Answer 6

Choroid becomes the iris in the front of the eye
Made of muscle that contracts to close the pupil when exposed to too much light.
Seperate muscles contract ton open the pupil when there is not enough light.

Question 7

What is the lens?

Answer 7

Located behind the iris
Biconvex shape
Flexible
thick - close
thin - far
Lens brings images to focus on the retina.

Question 8

What is the aqueous humour?

Answer 8

Liquid part of the eye
Mostly water
Acts as protection
Provides nutrients and oxygen
Eliminates waste

Question 9

What is the vitreous humour?

Answer 9

Clear gelatinous liquid
Back of the eye
Exerts pressure on the eye to help it keep its shape and hold the retina and lens in place.
Eliminates waste
Provides nutrients and oxygen

Question 10

What is the retina?
Remember r and c

Answer 10

Membrane composed of receptor cells that are sensitive to light
Converts light inton nerve impulse using rods and cones
rods - shape
cones - colour

Question 11

Objective

Answer 11

What are you being asked to do? Refer to the context.

Question 12

Variables

Answer 12

Independent - causes changes
Dependent - reacts to independent

Question 13

Hypothesis

Answer 13

If–independent–then–depenedent–because—explanation

Question 14

Materials

Answer 14

Bullet points
Good vocabulary

Question 15

Procedure

Answer 15

• No personal pronouns
• starts with a verb
• no data! just steps
• step-by-step, numerical order
• detailed
• don’t say ‘record results’, be specific (temp. conductivity, time, voltage, colour, etc.)
• Vocabulary
• Materials

Question 16

Data and results

Answer 16

Titles, units and calculations

Question 17

Analysis

Answer 17

connect theory to data
answer question and refer to context

Question 18

Conclusion

Answer 18

Answer the question!
Relate to context!

Question 19

Refraction

Answer 19

Refraction is a phenomenon by which light rays deviate when they pass from one medium to another with a different density. Light deviates from its path because it changes speed when it enters a different medium.

Question 20

When a light ray hits a different material

Answer 20

it is called an incident ray

Question 21

When a ray penetrates a different material,

Answer 21

it is refracted (bent).

Question 22

The normal line

Answer 22

is the line that is perpendicular to the surface. It crosses the point where the incident ray hits the surface.

Question 23

The angle of incidence is formed by

Answer 23

the ray and the normal.

Question 24

The angle of refraction is formed by

Answer 24

the refracted ray and the normal.

Question 25

What is myopia?

Answer 25

A person suffering from myopia, also known as near-sightedness can see objects that are close, but has difficulty seeing images that are farther away. This is due to an elongated eyeball, or lenses that are too thick. Their lenses bend the light too much, therefore the image is focused before the retina rather than directly onto it. This problem can be corrected with a divergent lens or biconcave lens, which will spread out or diverge the light rays so that they focus directly on the retina.

Question 26

What is hyperopia?

Answer 26

A person suffering from hyperopia, also known as far-sightedness, can see distant objects clearly but nearby objects appear blurry. This defect is caused by a shorter eyeball or by a lens that is not curved enough. The lens is unable to converge the light onto the retina and the image is focused behind the retina. This problem can be corrected by a convergent or biconvex lens, which will bend the light more, bring the light rays closer together, focusing the image on the rentina.

Question 27

What are biconcave lenses

Answer 27

Also known as divergent lenses. This type of lens causes light rays moving through it to diverge or split apart. It order to find the focal point of a divergent lens, you have to extend the refracted rays until they meet: this is actually called a virtual focal point.

Question 28

What are biconvex lenses

Answer 28

Also known as convergent lenses. This type of lens causes light rays that move through it to converge to go closer together. The rays will always converge to a precise point, we call this the focal point of a lens.

Question 29

Light rays under normal conditions

Answer 29

In a normal eye, not subjected to either myopia nor hyperopia, light enters the eye and is refracted so that the image is projected directly onto the retina which then transmits the light (stimulus) into a nerve impulse carried by the optic nerve and processed by the brain.
In other words:
Stimulus (light wave) - Recipient (eye) - Transformer (Retina) - Conductor (optic nerve) - Analyser (brain))