system
Given the following post, respond as if you're commenting on Reddit:
human
Why does hot water make more bubbles than cold when I'm washing my hands?

I've often noticed when using public sinks that if the faucet lets me get actual hot water i get a much better "foaming action" from whatever soap I'm using than if the water is cold. Is there a reason for this?
gpt
Hot water has less surface tension. This is also why it is better at cleaning. The molecules of warm water move around more than cold water and as a result are less tightly bonded. Soap works by bonding the hydrophilic end of a soap molecule to a water molecule. The other end of the soap molecule is hydrophobic and will bond to grease and dirt. The soap reduces surface tension even more making the water 'stretchy'. This is what makes bubbles. Because the warm water has less surface tension to begin with, the soap can more easily bond with the warm water molecules than the cold ones. This means the soap is more effective at bonding to the water and as a result more foaming action.