How do physicists measure the mass and weight of impossibly small matter?

Answer 1

Mass does two things:
i) it provides resistance to accelerations
ii) it couples to gravitational fields
- note that according to the equivalence principle of general relativity these two things could actually be the same thing.

To measure mass you measure one of those two effects. For example you strongly accelerate a small particle (eg by strong magnetic field) and measure the velocity it reaches in a given time. This measures its resistance to acceleration, hence its mass. Or you measure how it moves in a known gravitational field and infer its mass from that.


Hope this helps!
The Chicken

Answer 2

They do it with charged particles. They know the charge of an electron so they know the force a charge will have in a given magnetic field.

In a mass spectrometer they send it through an section that has an electric and a magnetic field so that the force is the same for only particles going a certain speed.
Next they send it into a magnetic field that turns the particle.
The bigger the particle the more time it takes to turn and the bigger an arc it makes.
There are other ways to do this, but they use the same principles.

For more info look up mass spectrometer in Wikipedia
http://en.wikipedia.org/wiki/Mass_spectrometer

Answer 3

Those people are wrong, I am sory. You can use energy. E=MC^2. So you measure the energy of the particle which has a specific mass associated with it!

Answer 4

It is all based on the gram.
For example, there is the nanogram.
1 nanogram = 0.000000001 grams

Look at the table in this link.

Answer 5

they don't....they estimate the number of particles in a given piece of mass and just divide.