How does pocket penetrometer work?

Answer 1

Using a newtonian spring. Simply put, the force applied by the spring is equal to the spring constant times the displacement. Therefore to achieve 1 ton/sq ft, the spring must be displaced a specific distance and because the area of the tip is known, it is easy to calculate the force. The equation would look like this:

Z = (x*K)/A

Z - Pressure

x - Displacement

K - Spring constant

A - Area of the Penetrometer tip

Because the spring is carefully selected the K is known or, at the very least, can be tested analytically to "calibrate" the gauge using a known force.

Answer 2

A pocket penetrometer is a handheld device used to measure the consistency of soil by exerting pressure on the surface. When the penetrometer is pushed into the soil, the resistance encountered is displayed on a scale, giving an indication of the soil's compactness or density. The higher the reading, the denser the soil.