All the Fancy Measuring Devices Used in Science Rely on Two Stone-Age Techniques

Humans quantify everything they can, from everyday devices to scientific instruments. Science uses models, such as equations, to explain how the world works, and then checks those models by measuring real-world values. Measurement with advanced tools still reduces to two basic methods: comparing things side by side or counting discrete units. Length can be measured by placing an object next to a ruler and reading the result, which depends on the ruler’s accuracy. A famous example of comparison measurement occurred in 1958 when MIT undergraduates used a person’s height as a unit to estimate the length of a bridge over the Charles River.

"Physicists build models to explain how the world works. It might be an equation, like the ideal gas law: PV = nRT. This tells us, for example, that if you double the temperature (T) of a gas, all else equal, its gas pressure (P) will double. But to see if the model is legit, or at least useful, we need to get some real-world values and check whether the equation holds. Modeling and measuring, measuring and modeling-that's science in a nutshell."

"With all of our cool tools, measurement still comes down to either comparison or counting. In that sense, it hasn't changed much since Noah built his ark from a spec sheet in cubits-the length of a human forearm from elbow to fingertip. Let me show you what I mean. Measuring length, for example, can be done by laying an object next to a standard and reading off the result."

"What you're doing here is comparing the length of a pencil and the length of a ruler side by side. (Of course this brings up another issue: How do you know if that ruler you bought online is accurate? That's a whole other discussion about standards. We can save that for another day.) The nuttiest comparison measurement ever took place in 1958 when a group of MIT undergrads set out to find the length of a bridge over the Charles River."

"They had the shortest member of their group, Oliver Smoot (5′7″, or 170 centi..."

Read at WIRED