1)physicist and mathematician are given a task:
to boil some water in a tea pot. They are both
given empty tea pot.
So they both fill it up with water and then
put it on a stove and boil it.
Now the problem becomes more complicated:
The tea pot filled with water is standing
on the stove. The task is the same.
PHYSICIST: turns on a fire and heats the water.
MATHEMATICIAN: Pours out the water and the
problem is reduced to the previous one.