Waves in the Creek

Waves in the creek.
Waves in the creek.

We talked about waves today down at the creek. The water was fairly calm so we could make some nice surface waves using floating leaves to show the up-down/side-to-side motion as the waves passed. I gave them 10 minutes to “play”, and more than one team tried to make a tsunami.

Creating a large wave.
Creating a large wave.

Since it’s allergy season, one student who could not go outside, read the chapter on the characteristics of waves and prepared a short–5 minutes–presentation for the rest of the class when we came back in.

Annotated image highlighting the crests of the waves and the wavelength.
Annotated image highlighting the crests of the waves and the wavelength.

The Apiary is in Business

Placing the nukes into the hives.
Placing the nukes into the hives.

As of this Saturday, we have two bee hives. With bees. Ms. Mertz and Mr. Deitrich received a pair of nukes (bees with a queen in a box) that were driven up, overnight, from Louisiana. They let them acclimatize for a few hours, with the nukes sitting on top of their respective hives, before putting them in. The nukes seem healthy; we were able to identify two queens and the bees were out foraging immediately. Ms. Mertz is happy.

Looking for the queen.
Looking for the queen.

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.

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.