Your hands up close are anything but smooth, with peaks and valleys, folds and rifts. 褶皱和裂痕。
There are plenty of hiding places for a virus to stick粘贴.
If you then touch your face, the virus can infect you.
But there are two extraordinarily simple ways that you can keep that from happening: soap water and hand sanitizer.
So, which is better?

The coronavirus that causes COVID-19 is one of many viruses whose protective outer surface is made of a lipid bilayer磷脂双分子层.
these lipids are pin shaped molecules whose heads are attracted to water, and tails are repulsed排斥 by it.
So in water-rich environments, lipids naturally form a shell like this with the heads outside and the tails inside.
Their shared reaction to water make the lipids stick loosely each other.
This is called the hydrophobic疏水性 effect.
This outer structure helps the molecular machinery of the virus break through cellular membranes and hijack our cells.
But it has thousands upon thousands of weak-points where the right molecules could pry窥探 it apart.

And this is where soap comes in.
A single drag of any brand of soap contains quadrillions百万的四次幂[乘方]之数,一千万亿 of molecules called amphiphiles which resemble biological lipids.
Their tails, which are similarly repulsed by water, compete for space with the lipids that make up the virus’s shell.
But they’re just different enough to break up the regularity of the virus’s membrane, making the whole thing come crashing down.
Those amphiphiles then form bubbles of their own around particles including the virus’s RNA and proteins.
Apply water, and you’ll wash that whole bubble away.

Hand sanitizers work less like a crowbar铁撬棍 and more like an earthquake.
When you surround a coronavirus with water, the hydrophobic effect gives the bonds within the membrane their strength.
That same effect also holds the big proteins that form coronavirus’s spikes in place and in the shape that enables them to infect your cells.
If you dry the virus out in the air, it keeps its stability, but now surround it with a high concentration of an alcohol, like the ethanol乙醇 or isopropanol异丙醇 found in most hand-sanitizers.
This make the hydrophobic effect disappear and gives the moloques room to move around.
The overall effect is like to removing all of the nails and mortar灰泥 from a house and then hitting it with an earthquake.
The cell’s membrane collapses and those spike proteins crumble崩溃.

In either method, the actual process of destroying the virus happens in just a second or two.
But doctors recommend at least 20 seconds of hand-washing because of the Intricate错综复杂的 of landscape that is your hand.
Soap and sanitizer need to get everywhere, including your palms手掌, fingertips指尖, outsides of your hands, and between your fingers, to protect you properly.

And when it comes to a coronavirus outbreak, doctors recommend washing your hands with soap and water whenever possible.
Even though the both approaches are similarly effective at killing the virus, soap and water has two benefits.
First, it washes away any dirt, which would otherwise hide virus particles.
But more importantly, its simply easier to fully cover your hands with soap and water for twenty seconds.
Of course, hand sanitizer is more convenient to use on the go.
In the absence of a sink, use the sanitizer as thoroughly彻底地 as possible and rub搓 your hands together until they’re dry.

Unfortunately, there are billions of people who don’t have access to clean drinking water, which is a huge problem at any time, but especially during an outbreak.
Researchers and aid groups are working to provide solutions for these communities.
One example is a devise that uses salt, water and a car battery to make chlorinated氯化的 water that kills harmful pathogens病原体 and is safe for hand washing.

So wherever possible, soap and water are recommended for a coronavirus.
But does that mean it’s best for every viral outbreak?
Now necessarily.
Many common colds are caused by rhinoviruses鼻病毒 that have a geometric几何图形的 protein structure called a capsid蛋白衣 instead of a lipid membrane.
The capsid doesn’t have nearly as many weak points where soap amphiphiles两性分子 can pry it apart.
So it takes longer for soap to be effective.
However, some of its surface proteins are still vulnerable to the destabilizing effect of hand sanitizer.
In this and similar cases, hand sanitizer may be more effective, especially if you then wash your hands to remove residual残余 particles.
The best way to know which way to use for any given outbreak is to do what’s best for all things illness-related.
Follow the advice of accredited官方认可的 medical professionals.