Chapter 1 : The Wonderful Wolrd of Science

We are surrounded by science!

A)Have you ever asked these Question?

• Why do plants need water?                                       

• Where do clouds come from?

 

 B) Exploring Science

 To exploring and study science, we need to observe things around us. We need to see, smell, hear, touch, touch and taste to find out about them. We use our senses to help us.

i) Sight

Your eyes are at work from the moment you wake up to the moment you close them to go to sleep. They take in tons of information about the world around you — shapes, colors, movements, and more. Then they send the information to your brain for processing so the brain knows what's going on outside of your body.

ii)Hearing

When an object makes a noise, it sends vibrations (better known as sound waves) speeding through the air. These vibrations are then funneled into your ear canal by your outer ear. As the vibrations move into your middle ear, they hit your eardrum and cause it to vibrate as well. This sets off a chain reaction of vibrations. Your eardrum, which is smaller and thinner than the nail on your pinky finger, vibrates the three smallest bones in your body: first, the hammer, then the anvil, and finally, the stirrup. The stirrup passes the vibrations into a coiled tube in the inner ear called the cochlea.

 iii) Taste

Taste is the ability to respond to dissolved molecules and ions called tastants.
Humans detect taste with taste receptor cells. These are clustered in taste buds. Each taste bud has a pore that opens out to the surface of the tongue enabling molecules and ions taken into the mouth to reach the receptor cells inside.
There are five primary taste sensations:

• salty
• sour
• sweet
• bitter
• umami

 iv) Touch
While your other four senses (sight, hearing, smell, and taste) are located in specific parts of the body, your sense of touch is found all over. This is because your sense of touch originates in the bottom layer of your skin called the dermis. The dermis is filled with many tiny nerve endings which give you information about the things with which your body comes in contact. They do this by carrying the information to the spinal cord, which sends messages to the brain where the feeling is registered.





v) Smell
Have you ever wondered what you smell when you "smell the roses" in the spring time? What makes a smell is something that is too small to see with your eyeball alone. It is even too small to be seen with a microscope! What you smell are tiny things called odor particles. Millions of them are floating around waiting to be sniffed by your nose!
You smell these odors through your nose which is almost like a huge cave built to smell, moisten, and filter the air you breathe. As you breathe in, the air enters through your nostrils which contain tiny little hairs that filter all kinds of things trying to enter your nose, even bugs! These little hairs are called cilia and you can pretend that they sweep all the dirt out of the nasal cavity, which is the big place the air passes through on it's way to the lungs. After passing through the nasal cavity, the air passes through a thick layer of mucous to the olfactory bulb. There the smells are recognized because each smell molecule fits into a nerve cell like a lock and key. Then the cells send signals along your olfactory nerve to the brain. At the brain, they are interpreted as those sweet smelling flowers or that moldy cheese.





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