Giant soap bubbles

Blowing Bubbles

Dip your pipe and gently blow.
Watch the tiny bubble grow
Big and bigger, round and fat,
Rainbow-colored, and then
SPLAT!

Margaret Hillert
Yes, today we are going to play with giant soap bubbles.
Not much to say about them, just that they make children smile and adults dream ... give a child a bubble, and its like you are giving her/him the magic itself.

What we need:

• 2 cups of washing dish detergent,
• 3 cups of warm water,
• four ounces of glycerine, buy it at the drugstore, the secret ingredient,
• large bucket, preferably with a lid,
• "Hula Hoop",
• small stool,
• rubber pool, the hula hoop must fit

How to:

1. Mix all ingredients in the bucket, water, detergent and glycerine;
2. Upon mixing the solution pour it in the pool;
3. Put the bow in the pool;
4. Place the stool inside it;
5. Equip your restless with goggles, fins, swimming suit, and whatever else you can remember of;
6. Lift the Hula Hoop in order to cover the child, he will found himself inside a giant soap bubble!;
7. Now, let your restless try it, replace him/her in the pool.

For better results:
The weather must be warm, wet weather works best
Heavy water makes this demonstration more difficult

But what happen in a soap bubble?

Surface tension
H2O molecules are in red and white
Blue circle:
hydrophilic end of the soap molecule,
Black "tail":
hydrophobic end of sap molecule

The soap is the main ingredient on a soap bubble; moreover, if you want to try, brands and different types of dishwasher detergent give different results. Soap is made of molecules with two distinct ends, one hydrophilic and another one hydrophobic. The first one attracts the water, the second repels it.
If we could cut a bubble we would see something like the picture, a water layer surrounded by two soap layers, one inside the other outside the bubble.
The interaction between the soap bubbles pushes the water molecules away from each other relieving surface tension.
On the other hand glycerine bonds with hydrogen in water preventing evaporation.
 
But a question remains:
With the hula hoop we can make spherical giant soap bubbles, but if we use a square form can we make square bubbles?...
 
Answer
No
 
Why?
Because everything in Nature happens with the minimum possible energy spent. This is a basic fact of Nature.
Surface tension of the bubble "is going to shape" it in a form with the less possible area to contain that volume. That shape is the sphere- also called bubble- the most effective shape in universe when comes to energy saving. Look the Sun, the planets, the water drops, the berries, and I am sure you can remember a few more spheres

Et Voilá!
Who would say we can learn with sop bubbles?
 
Enjoy!