Question: How does a hair dryer/blow dryer take in air so fast?

Caitríona Sheridan answered on 19 Nov 2019:

If you look at the structure of a hair dryer it is wider at the back, where it takes in air, than at the front where the air comes out. The smaller vent compresses the air so it comes out quicker. Also as the air is heated this further increases the pressure to get out the smaller vent! If you have a look for Boyle’s law, which is a thermodynamic law this might also help! Thanks for an interesting question!