Tell Me why

Science is not only about studying theories and equations,its basically understanding how things work. We come across certain intresting facts almost everyday but seldom to we give them a thought.

Why when milk is boiled does it raise up unlike water?
Milk contains 87 per cent water, 4 per cent proteins and 5 per cent lactose (milk sugar). When we boil milk, the fat, sugar, proteins and minerals get separated. Since they are lighter than milk they get collected on the surface in the form of cream. During heating water gets converted to vapour and rises up but is trapped by the creamy top layer and on expanding gives rise to foam on the top. On further heating ,more amount of water gets converted into vapours giving rise to pressure which in turns lifts the creamy layer to the top.

Why, when you boil a pan of milk, does the steam rise from it only when you remove it from the heat and not before?
Boiling point of water is 100 degrees where in the water gets converted into gas which is actually invisible. When cooled below 100 degrees some of the gas condenses back to form drops which is being scattered by light which we see as steam which is nothing but water particles suspended in the air that are scattering light. Milk has a higher boiling point and hence when heated one cannot see the water particles but can see them when its cooled cause to see the steam the temperature has to be below 100 degrees.

Do you get shocks during winter?

The shocks that you experience is nothing but transfer of charges. During winter due to climatic conditions our body gets charged (static charge). On touching any conductor like metal,water the charge from our body is transfered,giving rise to shock.

Its safe to sit inside a metal car during lightning.How?

The metal car get charges during lightning, this charge spreads on the surface of the car forming an electrostatic sheilding (In an elctrostatic shielding the charge inside is zero).Hence the one sitting inside the car is safe.