What role does glycerin or sugar play in bubble formula?

Question

From: http://bubbleblowers.com/homemade.html

Exploratorium Bubble Formula from the Exploratorium web site 2/3 cup Joy dishwashing soap 1 gallon water 2 to 3 tablespoons of glycerin (available in pharmacies or chemical supply houses)

Cyndi's Bubble Recipes from the Nathan's Wish web site 1/2 cup of dishwashing liquid (Dawn or Joy) 2 cups of water 2 teaspoons of sugar

What role does glycerin or sugar play in bubble formula? Are sugar or glycerin better than each other in some way w.r.t this formula?

Answer 1

From:

https://www.scientificamerican.com/article/bring-science-home-best-bubbles/

The solution with only water and detergent probably made smaller, shorter-lived bubbles compared to the solutions with glycerin or corn syrup. Bubbles burst when the layer of water molecules between the detergent molecules evaporates. But Glycerin and corn syrup form weak bonds with the water molecules and slow down the evaporation process, thus improving the life span and durability of the bubble. Glycerin makes stronger, longer-lasting bubbles, but corn syrup is often substituted in bubble solutions because it is cheaper. Can you find other substances around the house that can be added to water to make a bubble solution? If you try products such as shampoo or liquid hand soap, you can check their ingredients to see what might be helping to make the bubbles form.