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Natural sciences

Grade 4

Life and way of living

Module 5

The senses of smell and taste

Activity: To learn more about the senses of smell and taste [LO 2.1]

When you eat, the tongue tastes the taste of the food and your nose smells the flavour. This is how it works:

The openings of your mouth and nose come together in your throat, behind your mouth. The flavours of the food that you eat go to your nose from the back of your mouth. From there, nerves take a message to the brain and the brain tells you what you smell.

The tongue is rough and covered in taste buds to determine different tastes. Write down what the four tastes are that your tongue can identify:

Now pinch your nostrils together with your fingers to close your nose and drink some tea or cooldrink. Why is the taste different?

What have you noticed when you eat while you have a cold?

The sense of smell is very important in the animal world.

Write a proper sentence to say something about the sense of smell of each of the following animals.

Skunk:

Jackal:

Dog:

Antelope:

Rhinoceros:

Hoopoe:

Think of other ways in which animals are able to protect themselves because of their sense of smell.

Try this: Ask someone to mark a route with vanilla or vinegar, without you seeing it. Then try to follow the route by depending on your sense of smell!

Assessment

LEARNING OUTCOME 2: CONSTRUCTING SCIENCE KNOWLEDGEThe learner will know and be able to interpret and apply scientific, technological and environmental knowledge.

ASSESSMENT STANDARD 2.1: The learner is able to recall significant information.

Memorandum

a. sweet

b. salty

c. bitter

d. sour

When the nostrils are pinched together, scents cannot enter the nose, so you will only distinguish sweet, sour, salty and bitter.

In the case of a cold: the same as above.

The sense of smell in the animal world.

Skunk: Protects itself by spraying a strong smelling / pungent secretion in the direction of the enemy.

Jackal: Depends on its sense of smell when hunting. It also has scent glands that secrete scent as it goes along and helps it to find the way on its return.

Dog: Smells very well. Because of their well-developed sense of smell, dogs are used to sniff out drugs, explosives and even people in crowds. They also use their sense of smell when they are hunting.

Antelope: Uses its sense of smell to stay out of danger. If they smell an enemy, antelopes run off very quickly.

Rhinoceros: They also have scent glands underneath their feet to leave messages for other rhinoceroses.

Hoopoe: Birds usually keep their nests very clean, but not the hoopoe. Part of its defence mechanism is to not clean the nest so that the smell will keep predators away.

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Source:  OpenStax, Natural sciences grade 4. OpenStax CNX. Sep 18, 2009 Download for free at http://cnx.org/content/col11096/1.1
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