The luster of the surface of the aluminium utensils in the house is lost after a few days. Why does this happen?

Sometimes, yoghurt becomes bitter and froths up. Why does this happen?

Answer the following questions In the case of refraction og light through a glass slab, the emergent ray is parallel to the incident ray , but it is displaced sideways. Why does this happen?

You must have seen or read the news of dead fishes or oily water accumulating at the sea coasts. Why does this happen ?

Observe your mother while she elephant's foot (Amorphophallus) or arum leaves. Your hands may also begin to itch if you try to cut these leaves. Why does this happen? Try to find out. Ask your mother what she does to prevent the itching.

You may have seen how a drunken person struggles to maintain his body balance. An excess of alcohol in the body causes one to lose control over it. Why does this happen? Find out the reason with help of the internet.

Use your brain power Sometimes, yoghurt becomes bitter and froths up. Why does this happen ?

Explain the following: When a copper coin is dipped in silver nitrate solution, a glitter appears on the coin after some time, Why does this happen? Write the chemical equation.

Give reasons : It is easy to cut vegetables , fruits with a sharp knife . A blunt knife does not work here . Why does this happen ?

You must have read the news about many deaths due to poisonous liquor. Why does it happen?

Write answers to the given question in your own words: On pouring water in an oil cladded dish,water does not spread but forms small round drops.Why does this happen?