Water - Class 7 Science Revision Notes

• Water pollution.
  • Causes of Water Pollution
  • Effects of Water Pollution.
  • Controlling Water Pollution.
• Conservation of Water
  • Ways of Conserving Water.

Water Pollution

This involves making water impure or contaminating it.

Causes of Water Pollution

• Floods
• Human and animals waste
• Oil spillage
• Waste from industries.
• Uncontrolled use of farm chemicals.
• Acid rain

Effects of Water Pollution.

• Blocking the root hair.
• Acidic rain causes harm to plants since they cannot grow well in acidic rain.
• Dissolved chemicals substances and fertilizer may cause harm to animals.
• Oil spillage prevents entry of oxygen in water leading to suffocation and death.

Controlling Water Pollution.

• Practising proper hygiene.
• Practising farming methods.
• Drawing water for animals instead of taking them to water sources.
• Controlling the dumping of industrial waste into water sources.
• Clearing accidental oil spills as soon as they happen.
• Controlling the use of farm chemicals.

Conservation of Water

Conservation means proper care and use of water sources.

It ensures water isused sparingly and conserved for future use.

Ways of Conserving Water.

• Harvesting rain water.
• Recycling water.
• Re-using water.
• Using water sparingly.
• Mulching and shading.
• Construction of dams