American Culture

Conversion rates in science writing

by Djerrid

Here’s a math word problem that will give you painful flashbacks to the 7th grade:

According to, a proton moving at 99.9999991% of the speed of light has the energy of seven mosquitoes.

Also according to that site, three-hundred trillion protons moving at that speed has the energy of a 200 tonne train running at 200 kph.

Using this information, how many mosquitoes would it take to push a one kilogram ball to a speed of one kilometer per hour?

Science reporters for news outlets have an interesting job; some of the smartest people in the world have dedicated a lifetime of work to the most complex phenomena this universe has to offer and these reporters have to distill it down to a few hundred words at an 8th grade reading level. Many of us gripe at the quality of reporting with these restrictions, but it is not an easy thing to do.

One of the tricks of the trade is to convert some of these mind-boggling concepts into things you deal with every day. How many microscopic objects are compared to the width of a human hair? A common analogy has the Earth as the size of a basketball with the moon the size of a tennis ball 24 feet away. Or if you scoop up a teaspoon-worth of a neutron star, it would weigh the same as all the people on earth put together. Everyone can picture mosquitoes buzzing around our heads. But who would have thought of it as a unit of energy?

That’s where some of these crazy conversion rates can get these writers can get into trouble. Take the problem above. If my math is correct, it should take the energy of over 52 million mosquitoes to move a couple of pounds to less than walking speed. That’s over a hundred pounds worth of mosquitoes. With all of these big numbers there are a lot of zeros flying around and its easy for both sides of the equation to not balance out at the end.

So, I guess the moral of the story is to take these scientific analogies with a grain of salt – which, by the way, is the same size as the space those 300 trillion protons would fit into if it were a gas.

12 replies »

  1. Heh. Those 300 trillion protons as a gas would fit into whatever volume was available – that’s the defining characteristic of a gas, after all.

    Drawing analogies is a pain, but sometimes it’s worth the effort. Sometimes it’s not.

  2. “How many protons are there in each beam? About 300 trillion. But if you were to slow them down and allow them to form a gas at normal temperature and normal pressure, the gas would occupy a space about one hundredth the size of a grain of salt.”

    Hey, don’t question the science man! It looks like normal temperature and normal pressure are the key words here. And that’s from the original link.

  3. Oh, Great Google! What is the Answer?

    one kilometer per hour = 4,800 furlongs/fortnight

  4. Djerrid – in that case, the writer still screwed up, just differently (my apologies for disparaging you, though – I thought you’d made the error, not the original source).

    The volume that the 300 trillion protons would have to be contained within in order to produce average pressure at average temperature (average temperature of what? The sun? The Earth? Room temperature? And would that average room temp be 25C or 20C, since both are “standard” room temps?) would be about 1/100th the size of a grain of rice.

  5. Now wait just a damn minute. The energy of 7 mosquitoes traveling at what speed (max., min., just crusing?) and on what vector relative to the object at hand? And do these mosquitoes crash into the ball at maximum velocity with their entire mass, thereby dashing their little brains out, or do they push gently against the ball and increase their push slowly. And if they do all crash into the ball, how do they manage to do that simultaneously so that the ball immediately accerlerates to terminal velocity?

    And what sort of surface is the ball on? Is the rolling friction equal to that of the train?

    I think you’d better rethink the calculations.

  6. Geeks never run down, E. We’re too amped up on energy drinks, coffee, mate, Mountain Dew, and our cola of choice to run down.

    Why do you think geeks party so hard? It’s because of all the booze needed to cancel out all the caffeine.