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(futuristic instrumental music)

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- Hi, I'm Julie from the Exploratorium.

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You've probably heard
that washing your hands

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with soap and water is
the most effective way

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of preventing the spread of coronavirus.

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Now the question is,

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why is soap so helpful?

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And the answer is due to the biology

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and the structure of the virus itself.

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Now many viruses, including coronaviruses

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are surrounded by a membrane.

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And this membrane is exactly the same

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as the one that surrounds our own cells.

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The membrane is made of molecules

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that have a really special property.

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They have one side that I've
represented in blue here,

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that likes water, it's a water-loving end,

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and then their other half
of them dislikes water,

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it's a water-hating end.

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It likes fats a little bit more.

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Now these molecules assemble together

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so that they have actually
two layers of them.

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One side lines up so the
water's facing on this end,

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and the other side lines up

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so the water's facing on that.

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And basically, a ribbon of
these surrounds the virus.

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Now the trick to inactivating this virus

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is to disrupt the membrane.

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Soap molecules have
very similar properties.

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They have one side that likes water,

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and an other side that's attracted to fat.

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That's why they're really helpful

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when you're washing your greasy dishes.

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If you can get a soap molecule

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into the virus membrane,

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it'll disrupt the
structure of the membrane,

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and that inactivates the virus.

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The other thing that soap is handy for,

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is it can help us investigate
the behavior of membranes.

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I have a tray of soapy water here,

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and a string that I've
threaded through two straws.

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If you wanna try this at home,

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we have instructions and a
recipe for it on our website.

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You can see that when
I pull up the straws,

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that a film forms.

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This is a soap film.

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And this membrane has the same behavior

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as the membrane around the virus.

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If I touch it with my dry hand,

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you'll see that it pops.

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And in fact, when the
coronavirus is on a surface,

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all it needs to do is eventually dry out,

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and it will be inactivated.

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However, if I now wet my finger,

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you'll see that my wet finger

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does not disrupt the membrane.

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You've probably heard that the virus

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travels in respiratory droplets.

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It needs these droplets of water

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to keep its membranes intact.

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Another thing you've probably heard

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is that if you don't have
soap and water available,

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hand sanitizers that
have 60% or more alcohol,

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are also effective in
inactivating the virus.

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I have some 70% rubbing alcohol here,

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and this time I'm gonna
pull up my membrane,

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and I have my finger
covered in the alcohol.

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And the moment I touch
the membrane, it pops.

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And so alcohol is another
way to inactivate the virus.

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Now alcohol tends to evaporate,

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and maybe that happens
before you've gotten it

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into all the crevices of your hands,

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so soap and water is
really the best choice.

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So keep washing your hands,

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and celebrate our hero: the soap molecule.

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(futuristic instrumental music)

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