F2 Worksheet 11.2 answers

F.2 Integrated Science                         11.2    How we see

i      Words to know:

	English term	Write the words again	Chinese term
1	Cornea	Cornea	角膜
2	Iris	Iris	虹膜
3	Pupil	Pupil	瞳孔
4	Lens	Lens	晶狀體
5	Retina	Retina	視網膜

i      Label the diagrams:

Eye lid

Eye lashes

Cornea

Pupil

Iris

White protective layer

                                                                                                    Retina

Cornea                                                                                        White protective coat

Iris                                                                                              Yellow spot

Pupil                                                                                           Blind spot

Lens                                                                                           Optic nerve

i      Fill in the table with the following parts of a human eye:

Retina                Optic nerve                  Lens                        Cornea           White protective coat                    Pupil                      Iris

          

Parts of our eye	Functions
Cornea	Protects the eye and allow light to pass through; helps to focus light onto the retina
Iris	Controls the size of the pupil and hence the amount of light entering the eye
Pupil	Allows light to enter the eye
Lens	Allows light to pass through and focuses light onto the retina
Retina	Contains light receptors that can detect light and produce signals
White protective coat	Protects the eyeball and give it shape
Optic nerve	Carries signal to the brain

i      Fill in the blanks:

1        Yellow spot is the part on the retina which gives the clearest vision.

2        The optic nerve leaves the eye at blind spot.
           At this point, there is no light receptor.

3        Iris controls the size of the pupil.

4        In bright light, pupil becomes smaller so that less light is allowed to enter the eyes.

5        In dim light, pupil becomes larger so that more light can enter the eyes.

6       When light from an object enters the eye, the cornea and the lens focus the light onto the retina, forming an sharp image.

7        Light stimulates the light receptors on the retina to produce signals
           which are then travel to the brain through the optic nerve.

8        The brain interprets the signals to give us the sense of sight.