The soft ball stage of sugar is the only stage where you can blow bubbles. Real,honest-to-goodness bubbles. I learned this in culinary school and it was a bright highlight of my fun two-year return to kitchen academics.
The bubbles don't last long, but there is no mistaking you have reached the proper stage. These are NOT the bubbles you see on cakes and sugar centerpieces, which are an entirely different animal. These bubbles deflate and break, making a sticky mess wherever they drop.
And of course you need something to do with the sugar once it has reached a soft ball stage. My top options are to immediately beat it into egg whites and make meringue, or to continue cooking and make caramels or divinity. In any case, I rarely miss this opportunity to play, even if soft ball is not my ultimate goal.
By the way the sugar is really hot, so don't try to catch the bubbles before they deflate and cool off.
And cleaning up the sticky sugar mess when you are done is definitely worth it.
So if you cannot tell from this blog, we have caramels and divinity in the shop right now...