Sometime, a crackling sound is heard whi | Class 8 Science Chapter Some Natural Phenomena, Some Natural Phenomena NCERT Solutions

Describe with the help of a diagram an instrument which can be used to detect a charged body.

Sketch larynx and explain its function in your own words.

Arrange the following boxes in proper order to make a flow chart of sugarcane crop production.

Make a labelled diagram of a candle flame.

What is metamorphosis? Give examples.

The following Table shows the total power shortage in India from 1991– 1997. Show the data in the form of a graph. Plot shortage percentage for the years on the Y-axis and the year on the X-axis.

Make sketches of animal and plant cells. State three differences between them.

Describe the construction of a kaleidoscope.

What is a constellation? Name any two constellations.

Complete the crossword with the help of clues given below:
Across
1. This is necessary for photosynthesis.
3. Term for component present in the cytoplasm.
6. The living substance in the cell.
8. Units of inheritance present on the chromosomes.

Down
1. Green plastids.
2. Formed by collection of tissues.
4. It separates the contents of the cell from the surrounding medium.
5. Empty structure in the cytoplasm.
7. A group of cells.

What are antibiotics? What precautions must be taken while taking antibiotics?

Phases of the moon occur because

(a) we can see only that part of the moon which reflects light towards us.
(b) our distance from the moon keeps changing.
(c) the shadow of the Earth covers only a part of moon’s surface.
(d) the thickness of the moon’s atmosphere is not constant.

Explain why sportsmen use shoes with spikes.

A pendulum oscillates 40 times in 4 seconds. Find its time period and frequency.

Fill in the blanks :
(a) Phosphorus is very _________ non-metal.
(b) Metals are ________ conductors of heat and ________ .
(c) Iron is __________ reactive than copper.
(d) Metals react with acids to produce _________ gas.

Lightning and thunder take place in the sky at the same time and at the same distance from us. Lightning is seen earlier and thunder is heard later. Can you explain?

List sources of noise pollution in your surroundings.

What is the difference between noise and music? Can music become noise sometimes?

Which of the following voices is likely to have minimum frequency?
(a) Baby girl (b) Baby boy
(c) A man (d) A woman

Explain why a charged body loses its charge if we touch it with our hand.