This is one of the most popular and well known whisks. It is quite likely you have one (or many) in your kitchen as you read this.
The reason that the balloon whisk is popular is because it functions as a general purpose whisk that does the job well.
Balloon vs French Whisk
The two most common whisks in use are called the "Balloon" and the "French". This page is about the balloon whisk. Comparing them is a great way to illustrate what a balloon whisk is and how it got its name.
Note the wide round profile of the balloon whisk and the narrow skinny profile of the french whisk.
How to use a Balloon Whisk
Gather your tools and ingredients.
Place whisk into bowl.
Move whisk vigorously side to side until what you are mixing is the desired consistancy or fully combined.
Use whisk in some clear water for easy pre-cleaning.
What to look for when you buy:
While all balloon whisks share the common shape, there are many different sizes and materials used.
Mini: 0 to 4 inches. Mini whisks are often toys or decorative.
Cocktail: 6 to 12 inches. With very small "heads" that will fit into a drink glass.
Small: 8 to 10 inches. These are the sizes loved by very small hands.
Average: 11 to 14 inches. These are the sizes found in most kitchens
Large: 14 to 48 inches.
Whisk Materials / Surfaces
Stainless Steel: Balloon whisks are most often made of stainless steel wire tines.
Silicone: These are also made using silicone, creating colorful and softer tines. It should be noted that the silicone whisks are more bendy and floppy than the stainless steel wire ones.