### Video Transcript

Many chemistry conferences have held a 50-trillion angstrom run. How long is this run in meters? One angstrom is equal to one times 10 to the minus 10 meters.

The angstrom is a unit that is commonly used in 𝑥-ray crystallography for crystal spacings or 𝑥-ray wavelengths. This is because, by using angstroms, the numbers are in the range of one to 10, so they’re easy to handle. One angstrom is also equal to 0.1 nanometers and 100 picometers. So, it is sometimes used in the context of bond lengths. Our job is to work out how many meters our chemists have to run in the 50-trillion angstrom run.

One trillion is the same as one followed by 12 zeros or can be written as a power of 10, as 10 to the 12. So, 50 trillion angstroms can be written as 50 times 10 to the 12 angstroms. If you liked, you could simplify this to five times 10 to the 13.

We’ve been given the conversion factor between angstroms and meters. So, to get the length in meters, we multiply 50 times 10 to the 12 angstroms by one times 10 to the minus 10 meters per angstrom. This gives us a final value of five times 10 to the three meters, which is the same as 5000 meters, or five kilometers, which is a decent distance for a chemist to run.

So, just one question remains. Why do chemistry conferences use a unit that’s totally inappropriate for the length of distance? 5000 meters is definitely much easier to say than 50 trillion angstroms, and it’s definitely easier to write. Well, the truth is, it’s all in good fun, and it’s not meant seriously. And it means that we get to practice our conversion skills. We’ve proved that a 50-trillion angstrom run is the equivalent of 5000 meters.