Question

What's the difference between direct and indirect measurements? and which is better

Answer 1

Direct measurement are those in which measurements of objects are taken directly using some instrumemts directly like that of using scale, verenir calliper, inch tape for measuring length depending upon diffrent scale required which give magnitude with instrument unit also called as absolute measurement

EXAMPLE: weighing a cuboidal metal on a weigheing machine, measuring height of a building using some meter sacle instrument.

Where as indirect measurements method are those in which measurements are taken through diffrent process or experiment which will lead to desired result and scale like for measuring wind speed i would be using wind mill with power it produces i will do a reverse calculation and get speed of wind.

More example: measurring weight by calculating volume and multiplying it by density will give exact weight, measuring height of building using throwing ball from height calculating time of reach and then using equation of motion to get distance travelled or optical experiment of laser, light could be used

As in direct measurement most of the things involve instrument which may produce a error due to calibaration or some other,like we can have a thing so long that measuring it with instrument would be not posiible in once so again and again going for using short instrument will take a long time and more scaling error..

Whereas if we use measuring experiments of optics, kinamatics, work energy conservation laws with precise calculations to find it wil give a better and a sooner asnwer using indirect method that's why it is better than direct measurement.