Building Blocks of the Universe

When the people who proposed the metric system originally created the measurements used in many countries and in most scientific work, they created standard lengths and measures against which other measuring devices would be tested. There was a standard meter stick, a standard kilogram weight, and so on.

But as science advanced, the need for even more precision in measuring arose -- and the standards themselves were not as unchanging as people once thought. Though protected as much as possible from outside interference -- wouldn't do to have someone drop the kilogram and nick a piece off of it, for example -- the regular processes of atomic decay and other physical transformations continued. The meter stick looked the same to the naked eye and every meter stick measured against it could be calibrated well enough to do every day measurements, but it had altered enough that some of the very smallest measurements that scientists needed to make could not be made accurately enough using it.

So new standards were created, that relied on unchanging physical phenomena, such as wavelengths of certain radiation. But the standard kilogram is still measured against a physical object. Since 2010, scientists have suggested defining the standard kilogram in terms of the Planck constant, and the measurements for that are supposed to be finished this year. That constant, labeled h, is the smallest division or quanta into which physical action can be divided. Since it's so small, defining h can require some very precise measurements.

Or, as this article in Physics World suggests, you can do it at home with Legos. The actual machine that measures the constant is called a watt balance, and it can be built with the famous plastic blocks. While the Lego version of the watt balance will not have the precision of the multi-million dollar device constructed in a lab, it can do it well enough for almost any measurement used in everyday life.

Except for measuring the pain of stepping barefoot onto a Lego brick at night. That cannot be quantified with current technology, and it may never be.