DAV SCIENCE CLASS IV

Water Pollution D1.Name any two materials which can make rain water impure. Ans:Dust and smoke are the  two  materials which pollute the rain water D2.Name two human activities which can cause water pollution? Ans: Washing clothes  and bathing in river or pond pollute the water. D3.Which two pollutants are often dumped by factories into the river? Ans: Harmful chemical and solid waste materials are dumped into the river by the factories. D4.Name any two diseases that can be caused by drinking polluted water. Ans: Two diseases that may causes by drinking polluted water are jaundice and cholera. D5.Write the names of two types material, used by farmers to increase the production of crops. Ans: Pesticides and chemical fertilizer are the two types of material used by farmer   to increase the crop production. E1.How do wastes from factories and fields affect the aquatic animals? Ans: Agricultural and industrial waste increase the number of micro-organisms in water ,which increa

SAFE HANDLING AND STORAGE OF WATER D1.State the meaning of the term potable water. Ans: Water which is clean,germ free and fit for drinking is called potable water. D2.Name any two diseases that can be caused by drinking unclean water. Ans:Two diseases that can be caused by drinking unclean water are diarrhea and jaundice D3.Name the diseases which are spread by mosquitoes. Ans:The diseases spread by mosquitoes are malaria, dengue, chikungunya and filaria. D4. How does boiling help in making water safe for drinking? Ans:Boiling kills the germ present in water and make safe for drinking. D5.Name two methods of purification of water. Ans:Two methods of purification of water are boiling and chlorination. D6.Name any two ways of safe handling of drinking water. Ans:Ways of safe handling of drinking water are: i)Water should be stored in clean and covered container. ii)we should not dip our hand in water stored for drinking . iii)We should use ladle