Solid geometry word problems

Manuel bought a balloon (that is a perfect sphere) with a radius of $2 \text{ cm}$2, start text, space, c, m, end text. He wanted his balloon to be bigger, so he blew $2$2 big breaths of air into the balloon. Each big breath increased the balloon's radius by $1 \text{ cm}$1, start text, space, c, m, end text.

What is the ratio of the current volume of the balloon to the original volume of the balloon?