Warning: Disgustingness lies ahead

So I've been coughing a bit, sore throat and 'viral infection' and all.

This morning, I had a pretty nasty coughing fit. I rushed to the bathroom and spat out the gob of phlegm into the toilet bowl. To my surprise I noticed that the phlegm floated on the water like a water lily.

This led to the question, is phlegm less dense than water? Google couldn't give me an answer, so I assume that no one has researched this topic.

Or it could just be that I have a phlegm-buoyant cough (rimshot!)

Don't say I didden warn you.