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Adolescence: A Stage of Growth and Change - Physical activities

Grade 7CBSE

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

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Adolescence is the period of life between childhood and adulthood (roughly ages 1111 to 1919), characterized by rapid physical, mental, and emotional changes.

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Puberty is the specific stage within adolescence when an individual becomes capable of reproduction.

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Increase in Height: This is the most visible change. Growth occurs in the long bones of the arms and legs. While the rate of growth varies, it is influenced by genes and nutrition.

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Physical Activity: Engaging in outdoor games, yoga, and regular exercise is essential during this stage to build muscular strength, improve cardiovascular health, and maintain mental well-being.

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Nutritional Needs: Adolescents require a balanced diet containing proteins, carbohydrates, fats, vitamins, and minerals. Iron is particularly important for blood formation, represented as Fe2+Fe^{2+} in biological processes.

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Secondary Sexual Characteristics: These are physical features that distinguish males from females, such as the growth of facial hair in boys and breast development in girls, triggered by hormones like testosterone and estrogen.

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Personal Hygiene: Increased activity of sweat and sebaceous (oil) glands can lead to acne. Frequent bathing and cleanliness are vital to prevent bacterial infections.

📐Formulae

Calculation for full height (cm)=Present height (cm)% of full height at this age×100\text{Calculation for full height (cm)} = \frac{\text{Present height (cm)}}{\% \text{ of full height at this age}} \times 100

BMI (Body Mass Index)=Weight in kg(Height in m)2\text{BMI (Body Mass Index)} = \frac{\text{Weight in kg}}{(\text{Height in m})^2}

💡Examples

Problem 1:

A boy is 99 years old and is 135 cm135 \text{ cm} tall. If at the age of 99, a boy typically reaches 75%75\% of his full height, calculate his expected final height at the end of the growth period.

Solution:

Expected full height: 13575×100=1.8×100=180 cm\begin{array}{r} \frac{135}{75} \times 100 \\ = 1.8 \times 100 \\ = 180 \text{ cm} \end{array}

Explanation:

To find the full height, we divide the current height by the percentage of growth completed at that specific age (expressed as a decimal or fraction) and multiply by 100100.

Problem 2:

Calculate the Body Mass Index (BMI) of an adolescent who weighs 50 kg50 \text{ kg} and has a height of 1.5 m1.5 \text{ m}.

Solution:

BMI=50(1.5)2\text{BMI} = \frac{50}{(1.5)^2} BMI=502.25\text{BMI} = \frac{50}{2.25} BMI≈22.22 kg/m2\text{BMI} \approx 22.22 \text{ kg/m}^2

Explanation:

The BMI is calculated by dividing the weight (in kilograms) by the square of the height (in meters). It helps in determining if an adolescent's growth is within a healthy weight range.