1)How will you show that air is present in lamp of soil?
2)Why do fish not survive easily in polluted water?
3)Why is rainwater harvesting necessary?
Answers
Answer:
1) Take soil and pour water over it and within few seconds you will see few bubbles. These bubbles came due to the air spaces in the soil particles. The water filled up the spaces which were earlier filled with air. Now these air particles rise up as bubbles as air is lighter than water.
pour water to soil. you will notice that air comes out. this is because the air which is trying to escape from soil when you pour water to the dry soil.
Pour water on soil and you can see the tiny air bubbles or mix some dry soil in the water, you will see the air bubbles in water which confirms the presence of air in dry soil.
2) When nutrients wash into waterways through storm runoff, they deplete oxygen in the water that fish need to survive. Nitrogen and phosphorus typically enter streams and lakes from fertilizers, dog waste, and other sources. Over time, these nutrients build up in the water and promote algae and water plant growth, and as they decay, they lower oxygen levels in the water. Algal blooms can be harmful to fish as they feed upon algae, toxins accumulate within the fish, and when a predator fish consumes that fish, they too are consuming higher toxin levels.
Pesticides and heavy metals that enter waterways can also harm or kill fish. Synthetic pesticides used for weed and bug control are toxic in even small amounts. Heavy metals created when fossil fuels are burned enter the atmosphere, eventually making their way into bodies of water. Exposure to heavy metals can impair a fish’s ability to smell, disrupting its ability to locate food and protect itself from predatory animals and fish.
3) to save water for our daily use and for our future generations.