VIDEO EXPERIMENT : Soap vs Sanitiser

Published Mar 31, 2020



Despite the scientific appeal of hand sanitisers, plain old soap is better at eliminating Covid-19 from your hands, and it does not need to be anti-bacterial either.

Palli Thordarson, a chemistry professor at the University of New South Wales explains why normal soap is so effective at destroying Covid-19.

Thordarson likes to call Covid-19 “nano-sized grease balls” due to how the virus is constructed. The centre consists of genetic information that is encoded by ribonucleic acid (RNA) and it’s surrounded by a layer of fat and protein.

Thordarson explains that chemists call soap “amphiphiles”, the molecules of soap have two significantly different parts to it. On one side of the molecule, it’s attracted to water. And the other side is attracted to fats and proteins. Soap is, therefore, able to attach itself to water and the oil layer of Covid-19 which tears the virus apart when your hands are washed.

“It’s [soap] almost like a crowbar; it starts to pull all the things [Covid-19] apart,” Thordarson adds.

Now a perfect example to visualise this process is through the use of actual oil and water. Everyone knows how oil and water do not mix. But if you add soap, mix for longer than 20 seconds, the oil and water end up dispersing.

This is why soap is more effective than hand sanitiser. However, this process of pulling the virus apart is time-dependent. Soap needs a minimum of 20 seconds in order to achieve this.

Hand sanitisers work in a similar fashion although it has its limitations. It has to contain 60% alcohol and your hands cannot be wet or sticky. This will dilute the hand santiser and therefore be less effective.

So remember to wash your hands with soap for 20 seconds at least, and stay inside during the lockdown to reduce the speed the virus spreads. If everyone does their part, the country’s health system will be able to cope.

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