When it comes to measuring the "hardness" of a material, most tests are distinctly low-tech and basically involve pressing a diamond tip into the surface and measuring the size of the dent produced.

Real particles are lumps of energy that can be "seen" or detected by appropriate instruments; this feature is what makes them ...

Work close workEnergy transferred by a force. Work done = force × distance moved in the direction of the force. is done when energy is transferred from one store to another. Work is also done when a ...