Brainlag PlusHow small a nanoparticle is, nanometres in standard form, surface area to volume ratios, and the uses and risks of nanoparticles.
How small is nano?
1 nm (nanometre) = 1 × 10−9 m, a thousandth of a micrometre (μm).
Atoms are about 0.1 nm across.
- Nanoparticles: 1 to 100 nm across, a few hundred atoms.
- Fine particles (PM2.5): 100 to 2500 nm.
- Coarse particles (PM10, dust): 2500 to 10 000 nm.
- A particle is 45 nm across
- 45 × 10⁻⁹ m = 4.5 × 10⁻⁸ m
- 1 μm = 1000 nm, so 2.5 μm = 2500 nm
Before you compare two sizes, write both in the same unit, usually nm.
The rest of this lesson and its 9 practice questions are in Plus.
Screen 1 of 4, free to read.
- 9 exam-style questions, marked as you go, each with a worked solution
- Anything you get wrong is saved to your flashcards