The science behind hand washing
We found a fantastic video from Vox that explains how common soap works to destroy viruses.
Viruses like corona viruses are surrounded by a layer of fat that makes them waterproof, so washing with just plain water has little effect. Adding soap into the mix breaks down the fatty layer and destroys the virus completely.
But the process takes time so that’s why you are told to wash for a minimum of 20 seconds.