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Timelapse of Boulder’s Flagstaff Fire

Colorado has some pretty intense wildfires “of epic proportions1” going on right now. It seems fortunate in that only one person has died thus far (from what I’ve been able to determine) and about 600 homes have been destroyed, but almost 150,000 acres of land have been burned in five separate fires that are still ongoing.

The sunset/nighttime/sunrise sections2 of this timelapse video by Dustin Henderlong are a wonderfully poignant view of the Flagstaff wildfire in Colorado, which is about 30 minutes north of my alma mater.

via Devin Reams

  1. to paraphrase Colorado Springs Fire Chief Rich Brown describing the Waldo Canyon Fire, but really could be applied to all the fires in Colorado ↩

  2. starting at 1’32” and 3’45” ↩

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Vaporizing Lake Washington

Sometimes I wonder about interesting things, such as how much energy would it take to boil all the water of Lake Washington:

  • The volume of Lake Washington is 2.89 km31
  • The average lake temperature is 9.71°C2
  • It takes 4.19 Joules to raise the temperature of 1g of water by 1°C: \frac{4.19 \mathrm{J}}{ 1 \mathrm{g^{\circ}C \: _{H_{2}O}}}3
  • The density of water is \frac{1 \mathrm{g}}{1\mathrm{cm^{3}}}

Putting all that together, we get:

2.89 \mathrm{km^{3}} \times \left ( \frac{1000\mathrm{m}}{1\mathrm{km}} \right )^{3} \times \left( \frac{100\mathrm{cm}}{1\mathrm{m}} \right )^{3} \times \frac{1\mathrm{g_{_{H_{2}0}}}}{1\mathrm{cm^{3}_{H_{2}0}}} \times \frac{4.19 \mathrm{J\:} }{\mathrm{g^{\circ} C _{H_{2}O}}} \times \left ( 100^{\circ} \mathrm{C} - 9.71^{\circ} \mathrm{C}\right )= 1.093\times10^{18}\mathrm{J}

For comparison, the energy that hits Earth from the Sun in one second: 1.74 \times 10^{17} \mathrm{J}4

Basically, if we could focus all the energy from the sun that hits the earth, it would take…\frac{1.093\times10^{18}\mathrm{J}}{1.74 \times 10^{17} \mathrm{\frac{J}{s}}} = 6.281 \: \mathrm{seconds} …to vaporize Lake Washington5.

This is a vast oversimplification of the forces and energies involved, but I think it’s still a pretty good estimate.

Update: Apparently I missed one critical element, enthalpy/heat of vaporization \Delta{}H_{\mathrm{vap}}6. “This energy breaks down the intermolecular attractive forces, and also must provide the energy necessary to expand the gas (the PΔV work). For an ideal gas , there is no longer any potential energy associated with intermolecular forces. So the internal energy is entirely in the molecular kinetic energy.”7

What we have above is the energy required to bring it up to 100°C, but not to vaporize it. To actually vaporize water that’s already at 100°C, we need to add an additional \Delta{}H_{\mathrm{vap}} = 2260\mathrm{\frac{J}{g}}8

Running this number back through our calculations, we now get:
2.89 \mathrm{km^{3}} \times \left ( \frac{1000\mathrm{m}}{1\mathrm{km}} \right )^{3} \times \left( \frac{100\mathrm{cm}}{1\mathrm{m}} \right )^{3} \times \left (2260\mathrm{\frac{J}{g}} + \frac{1\mathrm{g_{_{H_{2}0}}}}{1\mathrm{cm^{3}_{H_{2}0}}} \times \frac{4.19 \mathrm{J\:} }{\mathrm{g^{\circ} C _{H_{2}O}}} \times \left ( 100^{\circ} \mathrm{C} - 9.71^{\circ} \mathrm{C}\right ) \right ) = 7.625\times10^{18}\mathrm{J}

This is still within one order of magnitude from my original answer and really only takes slightly longer for the sun to actually vaporize Lake Washington \frac{.625\times10^{18}\mathrm{J}}{1.74 \times 10^{17} \mathrm{\frac{J}{s}}} = 43.82 \: \mathrm{seconds} 9.

  1. http://wldb.ilec.or.jp/Lake.asp?LakeID=NAM-09&RoutePrm=0:;14:load;14:load; ↩

  2. Average of all temperature data for 2011 for the Lake Washington buoy: http://green.kingcounty.gov/lake-buoy/Data.aspx ↩

  3. http://www.merriam-webster.com/dictionary/calorie ↩

  4. According to Wolfram Alpha ↩

  5. ROM estimate ↩

  6. this is why I’m not a chemist ↩

  7. http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/phase2.html#c3 ↩

  8. http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/phase.html ↩

  9. still a ROM estimate ↩

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Pixar Story Rules

In an effort to improve my story telling, I’m leaving this link here as a reference for my future self. I’m a big fan of #19: Coincidences to get characters into trouble are great; coincidences to get them out of it are cheating.

I’ve always hated stories that fall back on deus ex machina1. I don’t want to write like that. There’s also come really good stuff in hear that I want to try out.

via Kottke

  1. “god from the machine“ ↩

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Stolen Plates

Got a friendly knock on my door this morning from the police. Someone stole the plates off my car in the middle of the night. Who does that? Apparently car thieves who needed clean plates for the white Subaru they stole last week.

At least they only took my plates, a trip to the License Plate office and $29.75 gets me new plates. Frustrating, but doable.