Why does a ship made of iron float while a piece of iron sinks in water?

Why machine parts becomes sticky in winter ?

Why do we wear white or light colour clothes in summer and dark colour clothes in winter ?

Why there is smog during winter season?

Why it is better to wear cotton clothes in summer ?

Why clouds are seen to be of white colour ?

Some varieties of wheat are known as spring wheat while others are called winter wheat. Former variety is sown and planted in spring and is harvested by the end of the same season. However, winter varieties, if planted in spring, fail to flower or produce mature grains within a span of a flowering season. Explain, why?

You may have seen the trick where a tablecloth is jerked from a table, leaving the dishes that were on the cloth nearly in their original positions. What do you need to perform this successfully? Which cloth should we use? Is it cloth made of thick cotton or thin silk? Should the dishes possess large mass or small mass? Is it better to pull the cloth with a large force or pull it with a gentle and steady force?

When a tiny circular obstacle is placed in the path of light from a distant source, a bright spot is seen at the centre of the shadow of the obstacle. Explain why?

Answer the following questions: (c) When a tiny circular obstacle is placed in the path of light from a distant source, a bright spot is seen at the centre of the shadow of the obstacle. Explain why?