You must have come across the word part per million, it is not the same as one in million. “Part per” is the usual way scientists talk about contents or concentrations of the chemical in air or water. Part per million counts the number of units of one substance per one million units of another. This technique allows the measurement of very small amounts of particles which make huge differences.
But it is hard to visualise what a part per million looks like. Here are a few ways to wrap your head around this.
32 seconds out of a year.
- A credit card lying in the middle of a football field.
- One step, on a 914 km walk.
- 1 key out of 11,363 piano keys.
- A single granule of sugar out of 273 sugar cubes.
- 1 second in 11 and half days.
- Out of 10 million bricks in the Empire State Building, only 10 would be one part per million.