Author: Lensyl Urbano

Hailstorm

Hail falls on the back porch.
Hail falls on the back porch.

A long winter is coming to an emphatic end with a series of dramatic spring storms. This hailstorm from April 3rd was one of the most remarkable I’ve experienced.

Hailstone with a glove for scale.
Hailstone with a glove for scale.

There was a bit of discussion about just how big the hailstones were. After all, could we say that the hail was the size of golf balls if only the largest were? Or would it be more honest to go with some sort of median or modal size.

Mr. Schmidt and Dr. Hurwitz discuss the semantics and logic behind the qualitative reporting of hailstone size.
Mr. Schmidt and Dr. Hurwitz discuss the semantics and logic behind the qualitative reporting of hailstone size.

Mrs. F. brought out the calipers and a rule for a few of the larger stones.

Measuring hailstone diameter.
Measuring hailstone diameter.

And I will report that the hail was large enough to put small dents in the roof of my car.

Hailstones banging off the roof of the schoolhouse, and off the cars in the parking lot.
Hailstones banging off the roof of the schoolhouse, and off the cars in the parking lot.

The infra-red satellite image below shows the frontal system that dumped the hail on St. Louis.

Infra-red satellite image showing the clouds of the frontal system that affected St. Louis on April 3rd, 2014. Image from NOAA.
Infra-red satellite image showing the clouds of the frontal system that affected St. Louis on April 3rd, 2014. Image from NOAA.
Weather map for April 3rd showing the mid-latitude cyclone that produced the hailstorm.
Weather map for April 3rd showing the mid-latitude cyclone that produced the hailstorm. Image from NOAA HPC.

The Eggs have Arrived

After waiting an eternity (about two weeks) the Middle School business’ eggs have arrived.

Eight eggs in their packing.
Eight eggs in their packing.

We set up the incubator downstairs in the pre-school/Kindergarden classroom so Mrs. D’s kids will have the chance of monitoring them. The little kids will be responsible for turning the eggs, while the middle schoolers have set up a data logger and a couple temperature probes to keep track of the temperature in the incubator.

The incubator was provided by Ms. Mertz. It’s put together out of plywood with a 75 W incandescent light bulb as the heat source. Unfortunately there is a significant thermal gradient and although we salvaged a couple of computer fans for the purpose we did not get around to installing them –and more importantly testing them– in the incubator before the eggs arrived.

We’ll see how it goes.

Radiolab: The Extinction of the Dinosaurs

RadioLab has an excellent podcast featuring Jay Melosh, a geophysicist who specializes in impact craters, and who advocates the hypothesis that the entire extinction event that killed off the dinosaurs at the boundary between the Cretaceous and Tertiary (the K-T boundary) took place over a period of two hours. The asteroid impact vaporized the crust of the Earth where it hit (near the Yucatan peninsula) and blasted this rock gas into space. There it cooled down to create little glass particles that reentered the atmosphere. On reentry the glass burned up, but there was so much of it that it raised the temperature of the atmosphere by several hundred degrees Celsius. Anything near the surface (mostly the dinosaurs) was cooked, but anything living just beneath the surface could have survived.