# Weekly Roundup 79

When it comes to the sciences it is hard to say that any are closer to maths than physics. Being able to model physical systems with a series of equations and then solving them to find out the result is one of the key aspects of physics. This almost completely sums up the work of a theoretical physicist and some may not be able to see the difference between physics and applied mathematics. For me, the key difference lies in the acceptance of uncertainty. First let’s imagine you’ve somehow got hold of the absolute metre stick, the metal rod that used to define the metre, and put perfect graduations down to the millimetre on it. If you were to measure the length of something, the chance that it falls perfectly on a graduation is almost impossible. You would probably look at the nearest millimetre and say this was the length, but you actually only know the length to within half a millimetre on either side (once the visual length passes half a millimetre either side you would start to record it as part of the next millimetre increment). In real life, uncertainties will be even bigger than this as you won’t have a perfect ruler to measure things with. Taking two rulers of two different makes and putting them next to each other (with both zero points next to each other) is quite interesting. You will be able to see how far along one begins to deviate from the other. It is the advantage of the mathematician to know their values to infinite decimal places and absolute certainty, but since physics has always stemmed from a scientific approach, these uncertainties have to be included in all measurements.

Until tomorrow, goodnight.