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Question
Collect data from your friends, neighbours and classmates to know more about “milk teeth".
Tabulate your data. One way of doing it is given below:
S.No. | Age at which first tooth fell | Age at which last tooth fel | No. of teeth lost | No. of teeth replaced |
1. | ||||
2. | ||||
3. | ||||
4. | ||||
5. |
Find out from at least twenty children and find the average age at which children lose the milk teeth. You may take help of your friends.
Solution
S.No. | Age at which first tooth fell | Age at which last tooth fel | No. of teeth lost | No. of teeth replaced |
1. | 6 year | 11 year | 20 | 30 |
2. | 6 year | 12 year | 20 | 28 |
3. | 7 year | 12 year | 20 | 28 |
4. | 7 year | 13 year | 20 | 32 |
5. | 7 year | 13 year | 20 | 28 |
To collect data about “milk teeth,” ask at least twenty children the following questions:
- At what age did your first tooth fall out?
- At what age did your last tooth fall out?
- How many teeth have you lost?
- How many teeth have been replaced?
Calculating the Average Age:
- Sum the ages at which the first tooth fell out for all twenty children and divide by 20 to get the average age for the first tooth loss.
- Sum the ages at which the last tooth fell out for all twenty children and divide by 20 to get the average age for the last tooth loss.
RELATED QUESTIONS
List out the food items for healthy mouth and teeth.
Tick (✓) the foods that are good for your teeth and cross (x) the food that is bad for your teeth.
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Differentiate the following.
Incisors and Canines
Name the types of teeth present in an adult human being. Mention the functions of each.
Match the Column I with Column II and select the correct option.
Column I | Column II |
i. Heterodont | a. Teeth embedded in separate sockets in jaw bone |
ii. Diphyodont | b. Four sets of teeth |
iii. Thecodont | c. Two sets of teeth in lifetime |
How do you take care of your mouth and teeth?
Teeth are rooted in separate ______ in between the ______.
Label the below given Figure 2.1 as directed below in (i) to (iv) and give the name of each type of tooth.
- The cutting and biting teeth as ‘A’
- The piercing and tearing teeth as ‘B’
- The grinding and chewing teeth as ‘C’
- The grinding teeth are present only in adults as ‘D’
Open your mouth, look into a mirror and try to count the different types of teeth in your mouth. Compare them with Figure 2.3 on page 13 of your NCERT textbook. Record your observations in the table below:
Type of teeth | Number of teeth | |
In my mouth | In the figure | |
Incisors | ||
Canines | ||
Premolars | ||
Molars |
- Did you observe any difference in the number of teeth? If yes, could you identify which type of teeth showed the difference?
- Compare the number and type of teeth in an adult (say your parents or cousins who have reached the age of 25-30 or more). Note your observation.
Write a note on the teeth of humans.