EVERYDAY SCIENCE

Detailed explanation-1: -The Mohs scale is a mineralogically derived hardness scale. It is defined on the premise that every material with a specific Mohs hardness number will scratch all materials with lower Mohs hardness numbers and can be scratched by all materials with higher Mohs hardness numbers.

Detailed explanation-2: -Scratch hardness is measured with a sclerometer. Attempting to scratch a surface to test a material is a very old technique. The first scientific attempt to quantify materials by scratch tests was by mineralogist Friedrich Mohs in 1820 (see Mohs scale).

Detailed explanation-3: -The Mohs Hardness Scale is used as a convenient way to help identify minerals. A mineral’s hardness is a measure of its relative resistance to scratching, measured by scratching the mineral against another substance of known hardness on the Mohs Hardness Scale.

Detailed explanation-4: -The three most commonly used are the Brinell test, the Vicker’s Diamond test, and the Rockwell test. All three methods involve indentation of the material. The hardness is calculated by measuring the force applied and comparing this to some geometrical aspect of the indentation such as the surface area or depth.

Detailed explanation-5: -A skin prick test, also called a puncture or scratch test, checks for immediate allergic reactions to as many as 50 different substances at once. This test is usually done to identify allergies to pollen, mold, pet dander, dust mites and foods. In adults, the test is usually done on the forearm.