DELHI PUBLIC SCHOOL- ELECTRONIC CITY
SUBJECT: SCIENCE
FINAL TERM REVISION WORKSHEET-2
NAME: ___________ CLASS: VIII SEC: ____
TOPIC: - Reaching the age of adolescence, Materials: Metals and Non-Metals, Light,
Microorganisms: Friends and foe, Sound
1. Fill in the following blanks with suitable words:
a) Sexual maturity is reached at……………
b) Each normal body cell in humans contains…………….. pairs of chromosomes out of
which…………….. pair is of sex chromosomes.
c) Metamorphosis in amphibians is brought about by……. hormone.
d) A non-metal is used to make an antiseptic solution called tincture……………
e) Metals are……………. conductors of heat and………………
f) The angle of ……………. equals the angle of reflection.
g) A person 1 m in front of a plane mirror seems to be……… m away from his image.
h) Blue-green algae fix……………. directly from air to enhance fertility of soil.
2. Name six endocrine glands in the human body. Also name the hormones secreted by each
one of these glands.
3. What is meant by the ‘primary sexual characteristics’ in humans? State two primary sexual
characteristics in boys and two in girls.
4. Compare the Chemical Properties of Metals and Nonmetals in tabular form. (any three)
5. Name the part of the eye:
(a) which controls the amount of light entering the eye.
(b) which converges light rays to form the image.
(c) on which image is formed.
(d) which carries the image to brain.
(e) which changes the curvature (or thickness) of eye-lens to focus objects lying at various
distances.
6. What is meant by dispersion of light’? Name a natural phenomenon which is caused by the
dispersion of sunlight in the sky.
7. What are antibiotics? What precautions must be taken while taking antibiotics?
8. State the causative micro-organisms and modes of transmission of the following human
diseases:
(i) Tuberculosis
(ii) Measles
(iii) Polio
(iv) Typhoid
(v) Hepatitis B
(vi) Dengue
9. Draw a neat and labeled diagram of the human ear.
10. The sound from an insect is produced when it vibrates its wings at an average rate of 500
vibrations per second:
(a) What is the time period of the vibrations?
(b) What is the frequency of the vibrations in hertz?
(c) Can we hear this sound? Why or why not?
Answers
Answer:
1a)adolescent
b) 23 , 22+x or y
Answer:
(d) The changes occurring in body and mind during adolescence are a natural part of growing up. (e) The features which help us to distinguish between a mature boy and a girl are called secondary sexual characteristics. (f) The onset of puberty is controlled by hormones (g) The menstrual cycle in women is controlled by hormones (h) Each normal body cell in humans contains23 pairs of chromosomes out of which 1pair is of sex chromosomes. (i) X and Y chromosomes are called sex chromosomes. (j) Early marriage and motherhood cause health problems in the mother and the child (k) The protective foods are fruits and vegetables (l) Thyroid and adrenals secrete their hormones when they receive instructions from pituitary gland through its hormones. (m) Metamorphosis in amphibians is brought about by thyroxine harmone