One of the highlights for SAS was a tip from cage fighter Alex Reid, who told The Sun tabloid newspaper in April that he “reabsorbs” his sperm to prepare for a big fight.

“It’s actually very good for a man to have unprotected sex as long as he doesn’t ejaculate. Because I believe that all that semen has a lot of nutrition. A tablespoon of semen has your equivalent of steak, eggs, lemons and oranges. I am reabsorbing it into my body and it makes me go raaaaahh,” he said.

I think my favorite part is the specificity.  Steak, eggs, lemons, and oranges.  A combination that I’m sure will be known as the Ejaculate Platter when Mr. Reid retires from the cage and opens his line of signature restaurants. (Actually — per a google search that I never suspected I would type — it looks like he is a reader of Vice Magazine. (maybe NSFW) You don’t need to read the whole article, just scroll down and you’ll see what I mean.)

From now on, whenever I encounter people engaging in the fallacy of thinking that just because someone is successful that makes them generally worth listening to, I am going to imagine that they are earnestly telling me that a man having unprotected sex is one of the most nutritious of all possible activities.

An aside: I don’t recall having been explicitly introduced to the idea that the density of a black hole decreases as its mass increases before.  In fact I’m not sure that black hole density ever came up at all in my modern physics class, which is the only place I  worked with Swarzschild radii.  It’s obvious once presented, but when I got to that part of the video I was shocked to find I had been completely unaware of such a fundamental characteristic of black holes.

CreatureCast Episode 1 from Casey Dunn on Vimeo.

And here is the best video I was able to find of some of the actual behavior discussed by the interviewed scientist.  It is a different species of squid, but I think the same principles are in evidence.

I thought this was a very clever idea, and did a quick back-of-the-envelope estimate of what the energy saving should be.  For ease of approximation, I make the following assumptions:

• Assume a standard 40-gallon (151 liter) electric water tank, set to warm to 120°F (48.9°C).

• Assume that I use water in such a way that all the water in the tank has time to completely warm to the air temperature before I draw it into the water heater.  (Otherwise it would be necessary to model usage, flow rate, bring in Newton’s law of cooling, etc.)

• The table at the right gives the median ground water temperature in the United States as about 55°F (12.8°C).  I will use this as temperature of the water going into the heater without the uninsulated tank.

• Finally, assume that the ambient air temperature around the uninsulated tank is a constant 72°F (22.2°C) year round.  This is almost certainly a net underestimate where I live, a net overestimate in some places, and probably pretty close to correct if your water heater is in an air conditioned room (but then the energy use of the whole system is more complicated to calculate).

The specific heat of water is 4186 Joules/kilogram, so without the uninsulated tank the energy to heat one water-heater-full is (4186 J/Kg°C)(151 Kg)(48.9-12.8 °C)= about 22.8 million Joules.  With the uninsulated tank in the system, the equation changes to (4186 J/Kg°C)(151 Kg)(48.9-22.2 °C)= about 16.9 million Joules.  The difference is 5.9 million Joules, or about 1.63 kilowatt hours.  Assume that I use one full tank of water per day.  The current average price of electricity is 11.47¢/kWh, which amounts to a savings of $5.60 per month.

This is a really rough estimate, but it is enough to convince me that this alteration to home water heating is probably in the class of improvements that will pay for themselves in reasonably finite time.  Good on you, clever radio call-in man.