"It's about as long as my foot." "It's as heavy as a watermelon." Back then, without the need for precision, these measurements were acceptable. Things were initially measured arbitrarily. Of course, the world didn't start out using standards. Things are measured based on comparison to standards. Measurement must depend on rules called standards. Other ways need to be devised if you want to measure the mass of the sun, for example, through indirect measurement. An example for this is the weighing scale: it approximates the standard for mass. Whether it be a hydrogen atom or an apple or the sun, there needs to be ways to measure their mass based on that standard. If we have the standard for mass, we would need to work out a way to find out how heavy something is based on that standard. There needs to be ways of measuring based on the standard. Having a standard is not the end itself however. It also means that if something is three meters today, it would be three meters after ten years if nothing has changed about it. People have different lengths of feet, so what would be one foot for one person would not be one foot for another person.īut why is invariability important? Invariability is important because it allows for universal communication: what is three meters here will be three meters there, and thus anyone from any place can read about three meters and know how long it is. If instead we measured distance based on how long a person's foot was, it would be convenient, but it wouldn't be consistent. An important part of defining standards is invariability. For example, physicists have defined the meter as the distance travelled by light in a certain fraction of a second. People have agreed to define standard units to allow consistency. An example is the meter for measuring length. ![]() ![]() A unit is the standard chosen to which other things are compared to. The rules that are set in place are called standards. Measurements allow us to recognize three hours and see how it's shorter than five hours, without having to observe the hours passing by themselves. Measurements are an important part of comparing things, as they provide the basis on comparing objects to other objects. Scientists measure and create things to meet standards and measurements to extreme accuracy so that measurements can be found out precisely. Measurement is not arbitrary however: it is based on units. As measurements are important, rules are set in place to ensure that measuring is consistent. The need for measuring and comparing things is a very important part of physics.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |