It is difficult to burn a heap of green leaves but dry leaves catch fire easily. Explain.
It is difficult to burn a heap of green leaves but dry leaves catches fire easily because green leaves contains a lot of water. That water cools the leaves and the temperature becomes below its ignition temperature. This prevents the burning of green leaves. But in dry leaves, there is no water present. So, as the temperature raised above the ignition temperature, the leaves catches fire easily.
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.
What is a constellation? Name any two constellations.
Describe the construction of a kaleidoscope.
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 is a constellation? Name any two constellations.
Complete the cross-word puzzle using the hints given below
Across
1. The process of the fusion of the gametes.
6. The type of fertilization in hen.
7. The term used for bulges observed on the sides of the body of Hydra.
8. Eggs are produced here.
Down
2. Sperms are produced in these male reproductive organs.
3. Another term for the fertilized egg.
4. These animals lay eggs.
5. A type of fission in amoeba.
Arrange the following boxes in proper order to make a flow chart of sugarcane crop production.
Give two examples of each.
(a) Kharif crop
(b) Rabi crop
Make a sketch of the human nerve cell. What function do nerve cells perform?
Suppose you are in a dark room. Can you see objects in the room? Can you see objects outside the room. Explain.
Do all the stars in the sky move? Explain.
In case of a fire, before the firemen use the water hoses, they shut off the main electrical supply for the area. Explain why they do this.
Fill in the blanks with appropriate words:
(a) Synthetic fibres are also called ______ or _______ fibres.
(b) Synthetic fibres are synthesised from raw material called ________.
(c) Like synthetic fibres, plastic is also a __________ .
Explain how soil gets affected by the continuous plantation of crops in a field.