Grade Six Science
Hello Boys and Girls,
Have you been keeping safe? Remember to do all the things that will keep you and your family safe. We are now in a new month — the month of May. Time is going by very quickly so you must continue to work even harder. You must remain focused and constantly revise. These two things are the keys to success.
This week we will look at the senses and their organs.
The pictures above represent the sense organs. Can you name them and tell what each does?
We can sense and know about our environment through our senses. List the five senses again.
Let’s look at our eyes. Use a mirror to observe your own eyes. Look at another person’s eyes.
Now draw a picture of your eye to show
The the eyelids and eyelashes the white part the coloured part the inner black circle
eyes are the sense organs of sight through which we find out many things about our surroundings.
How many eyes do persons usually have? Why do we need Discuss this with your friend.
two
eyes?
Each eye is shaped like a small ping-pong ball. Since the eye itself is shaped like a ball, it is called the eyeball. Only a small part of each eyeball can be seen in front. Most of it is surrounded and protected by a deep, rounded space in the skull bone, called the socket.
Each eye is held in place by six muscles. These muscles move the eyes so that you can look at things all around you.
Let’s look at the parts of the eye more closely.
The skin which is used to cover the eye is called the eyelid – upper and lower. Look at the coloured part. It is called the iris. What colour is the iris of your eye? Your friend’s eye? When we refer to the colour of someone’s eye, we are really referring to the iris. The muscles of the iris control the amount of light entering the eye.
The pupil is a hole or opening in the centre of the iris. It allows light to enter the eye. The size of the pupil can change. The muscles of the iris regulate or control the size of the pupil. In dim light, the pupil gets larger allowing much light to enter, and in bright light it gets smaller, allowing a small amount of light to enter the eye.
The whole front surface of the eyeball is covered by a thin, clear layer. This is the cornea. It protects the front of the eyeball and makes it look shiny like glass. Behind the pupil is the lens through which light passes on to the retina. Find the parts discussed in the diagram below.
How do we see?
Light comes into the eye from an object. The lens help to make the image on the retina. The image is upside down and smaller than the object. When the image is formed on the retina, messages are sent along a nerve (the optic nerve) to the brain. The brain turns the image the ‘right – way up’ and helps us to understand what we are looking at.
Let’s find out how much you know about the eye. Answer the questions which follow.
1. 2. 3. 4. 5. 6. 7.
Draw and label the side view of an eye.
The eye is the organ associated with ……….
Describe how light enters the eye.
List two functions of the iris.
On which part of the eye is the image of objects formed?
How does the brain affect the image seen?
How should you care for your eyes? List at least two ways.
Until next week, goodbye Boys and Girls and do care your eyes!