water cycle and water purification

Question 1

water cycle

Answer 1

precipitation - infiltration- percolation- (evaporation ,exhalation , transpiration , surface runoff) - condensation

Question 2

water purification

Answer 2

smaller scale water purifications -
filtration using a muslin cloth (does not make water safe for drinking)
boiling - water must be brought to a boil for 10-20 minutes
chlorination- 50mh tablets can kill organisms in 20L of water
Larger scale water purification-
screening - water must pass through screening grid to remove large objects
sedimentation- the water is pumped to a settlement tank where fine suspended solids settle
filtration - clear water pass through filters containing microorganisms
chlorination - passes through chlorine to kill harmful microorganisms and then pumped into storage tanks

Question 3

testing water for bacteria

Answer 3

agar is a solution when hot forms a gel when cool and its nutrients allows bacteria to grow rapidly
steps- collected test of water , pour small amount of water onto agar plate and cover lid , incubate at 35*C for 24 hrs , count bacteria colonies

Question 4

human activities on water supply

Answer 4

harvest fresh water for agriculture, industrial and domestic use
release of harmful substances into bodies of water

Question 5

effects of contaminated water on humans

Answer 5

pathogens cause disease , pesticides cause malfunction in nervous system and endocrine system