MASS CARRIES LOT OF WEIGHT.

   

 In our daily life, we usually measure mass.  What is mass exactly?  Put a small child on a swing and push it.  You can easily do it.  Seat a 80 kg man on the swing.  It is difficult to push him.  Hence, mass is the measure of resistance given by the body to change its state or for its acceleration(inertia).  Mass can also be termed as a 'measure of inertia'.  

    But a weight is force on the body due to earth's gravity.  A body of 1 kg mass experiences 9.8 newton gravitational force.

f = mg
f = 1*9.8 newton
Hence its weight is 9.8 newton.

1. A mass remains the same everywhere but the weight depends on gravity.  A man weighs less on the moon but very heavy on the Jupiter due to gravity.

2. When gravity zero, weight is also zero.  That is why astronauts feel weightlessness and float in the space.  But still they carry mass and inertia.

3. When a thing moves in very high speed, its mass increases according to Einstein.

4. Mass can be converted into energy and vice versa.  This is the principle of atom bomb.
  In the sun, hydrogen atoms combine to form helium.  In this fusion process, there is a loss of mass which is converted into heat and light energy.

5. High frequency electromagnetic waves(like light waves) behaves like particle (mass). example: photon.

6. The mass of earth is 6 followed by 24 zeros in kg( 6*10^24).  The mass of electron is 9 preceded by 31 zeros after the decimal point(9*10^-31 kg).  Electron carry very less mass and hence less inertia.  So it can be easily sped up in the electrical wire.  But the earth has huge mass and inertia.  So even the atomic explosion does not disturb the earth's rotation.

7. In Apollo-15 mission, astronauts carried a hammer and a feather.  They dropped both of them on the moon simultaneously from the same height(no air on the moon).  Both reached the lunar surface at the same time.  It proves the old principle:  All the bodies are equally accelerated by the planet's gravity irrespective of their masses.

8. Latest news:  The particle called Higgs boson (god's particles) said to give mass to all the matter  in the universe. 

So the simple concept mass is really difficult one.