A certain critical mass of people with a highly spiritual consciousness will bring about a sudden change in the whole population.

The colloid initiated them when it reached a certain critical mass.

That cylinder volume holds equal amount of air which has a density and thus a certain mass.

I would guess that you must have a certain mass to keep the reaction going, but what is the minimum?

You wanna find out where a certain mass of friends are?

It is apparent that a certain mass of data is required for prosopography.

Dietary minerals are present in a healthy human being's blood at certain mass and molar concentrations.

"A certain mass is needed for the economics to make sense," Mr. Gray said.

One point has to be fixed, on a planet of a certain mass, but the other end is portable.

How would I go about finding the energy needed to melt a certain mass of polystyrene foam?