Ordes van grootte

In physics, we come across a vast range of objects, from quarks, the smallest thing that exists in the universe, to the sun, the largest thing we can see.

It is difficult to get a feel for the largeness or smallness of such objects. To express such quantities, we use the concept of orders of magnitude, or powers of ten method.

Here, all numbers are approximated to the power of ten closest to the given quantity. For example, the radius of the iron nucleus is 4.6 femtometers; this is not the exact value of the radius, but rather just an order of magnitude approximation.

4.6 femtometers can be written as 4.6 times 10 to the power negative 15; so, the radius of the nucleus has an order of magnitude of minus fifteen.

Orders of magnitude helps in making certain assumptions and simplifies calculations.

For instance, when calculating acceleration due to gravity on an object falling from a building, the building height is neglected, as it is few orders of magnitude less than the earth's radius.