Here's a quick video in which I show you how to make a movable hole in soap film
You could call it an anti bubble
You'd be wrong, but you could call it that I'm gonna call it that in the title
For the clicks and hear the clicks
It's quite surprising when you first see it and then you think about it for a bit and it kind of makes sense
But it's also a really useful metaphor for a cell membrane. I'll get to that in a minute
I'll first of all show you how to do it
All you need is some kind of frame I've used thick copper wire you then dunk that in some
soapy liquid to get your membrane you then drop a loop of thread onto the membrane and then you pop
the bit of soap film that's inside the loop and
The loop of thread suddenly jumps out into a perfect circle. Why does it form a perfect circle?
Well, the soap film is under tension because it's elastic. It's also fluid so it can move around and
energetically it's going to move in such a way as to minimize its area in the same way that when you
Open up a balloon the elastic membrane of the balloon will
minimize its area by
blowing air out of the balloon. When you introduce a hole into the soap film the soap film will minimize its area by
maximizing the area of the hole and you may know that for any
Given fixed perimeter like the fixed length of the loop of thread the maximum possible
Area is if you form that perimeter into a circle and that's why this wibbly-wobbly
Loop of thread suddenly pops into this perfect circle.
I came across this trick when I was doing some research for a kids book called the bacteria book
Soap bubbles are actually a really good metaphor for cell membranes like the membrane of a bacterial cell
Cell membranes and soap bubbles are both made of amphiphilic molecules
Which are molecules that have of hydrophobic end and a hydrophilic end and in the case of cell membranes their?
Phospholipids so look at one end. You've got these two
hydrocarbon chains and that's the same structure as oil and as you know oil and water don't mix so this is the
Hydrophobic end the end that doesn't mix with water
This ends got a hold of our stuff going on and it's polar so it does
Dissolve in water it's soluble in water. And this is very similar to the structure of soap
So you've got one end that will mix with the grease on your dinner plate
and you've got another end that will mix with the water in your sponge making it easier for you to
Remove the grease from your dinner plate
What's really cool is if you put some phospholipid molecules in water, then the hydrophobic ends will
Attempt to avoid contact with the water by facing each other and you end up with what's called a phospholipid
Bilayer like this soap film is very similar except
It's the hydrophilic ends that point inwards and there's a layer of water
sandwiched between the two and the metaphor doesn't end there here are some things that they have in common so both cell membranes and
soap film are
Fluid as you can see this hole is moving around and you get a similar thing with cell membranes you have these
molecules that float around
Within that phospholipid bilayer and these complex molecules have hole in them and it's for cell transport
It's to allow different molecules in an hour. Finally viruses often have this phospholipid
envelope around them
So from the outside
They look a bit like teeny tiny cells and it's believed that these envelopes are used to
Evade detection by immune systems because they just look like normal cells
and in fact
These virus envelopes are stolen from the host cells and actually you can demonstrate that happening with this
Model here. Imagine my breath is a virus pushing its way through a cell brain. They go look imagine
There's a virus inside that little bubble
This video was supposed to coincide with the release of my kids book the bacteria book, but I'm incredibly disorganized
This book's been out for over a year now. And in fact another book by me is out it came out last week
It's called Sciences magic. So I have three books for kids now in total the other one thing how to be a scientist
I'm not gonna bang on about these for too long
I will just say how to be a scientist and science is magic are both full of experiments that you can try at home
I worked really hard to make sure it wasn't just the bog-standard experiments you get in books like this
So there's loads of stuff in these books that you won't find anywhere else. I'm also really proud of the bacterial book
It's all about microbial life and the little characters and the illustrations and stuff done by DK
I just love them and I hope that you would too therefore kind of 5 to 11 ish years old
So I appreciate that's not really my YouTube demographic
But you know
maybe you have nieces and nephews that you keep forgetting to buy birthday presents for
Just get one of these or stick it in a cupboard and then you you're good to go
If you're interested in that and you feel like being generous then there are affiliate links in the description
You can have a look at and yeah, that's it
I hope you enjoy them and I hope you enjoyed this video
If you did, don't forget to hit subscribe, and I'll see you next time