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Category: STEM (Page 2 of 11)

Science, Technology, Engineering, Medicine

Coronavirus Covid-19 Quizzes

In the interest of getting more information on the Covid-19 virus out and in easily digested form, I’ve developed three educational quizzes. Those quizzes have been added to my existing quiz web site.

The Covid-19 virus is new and much is being learned. New discoveries are made and our knowledge refined every day. There are changes in what’s known every day. In compiling information for these quizzes, I found many examples where information published a week or two ago is already obsolete. These quizzes are based on the best information I could find as of March 18, 2020.

I will do my best to keep these quizzes up to date. Please comment here on this blog post with any updates or incorrect information you may find. Ideas for additional questions or additional quizzes are welcome. In fact, this blog post exists so that you have a place to leave comments.

Click here to go to the quizzes.

Consistent Forecast Temperature Error

A weather forecasting question:

For the past two months we’ve had one heat wave after another here in West Virginia. It’s been awful. High temperatures in the low 90s (Fahrenheit) with humidity giving a heat index around 100F. These conditions are 15 to 20 degrees above normal. Sometimes, it goes on for four or five days at a time without a single break. Then, there’s a one or two day break in the 80s, and then another heat wave. It’s now the middle of September, almost fall, and it continues. The forecast shows another heat wave next weekend, after the first day of fall.

An odd new thing I’ve never seen before that’s happening this summer is that forecast temperatures, both highs and lows, are consistently four or five degrees lower than the temperature actually reached. The forecast says 90, but it reaches 95. The forecast is 87, but it reaches 92. An error the other way around never happens.

As an engineer, I know that true errors are like noise and vary randomly to either side of the correct value. If the error is consistently to one side or the other, then there’s a systemic problem or calibration error.

Here’s the question. As an amateur meteorologist for over 50 years, this got me thinking. Long ago, before the powerful computer weather models of today, the historical average temperature was factored into a weather forecast. I don’t know if that’s still the case today. Might it be that I’m observing one of the effects of climate change? The climate is changing, today’s temperatures are above normal, and the historical weather data is biasing the forecast several degrees too low? Is that what’s going on?

I invite anyone who might know the answer to comment below. Thank you.

Those Tiny Bubbles When You Boil Eggs


If you’ve ever boiled eggs, you’ve surely noticed tiny streams of microscopic bubbles coming from various points on the eggs as the water heats up. I figured this was dissolved air in the water and there were tiny “flaws” on the shell that formed nucleation sites for the bubbles. This is a nice explanation but totally wrong. I’m an engineer, not a zoologist. The correct answer is quite amazing, even mind-blowing to an engineer.

Basic structure of an egg

The truth is that bird egg shells are fabricated with microscopic breathing holes so the chick can breathe while it breaks its way out of the shell. Those tiny bubbles are air trapped inside the egg that expands when heated and streams out of the breathing holes. For me, learning this was kind of stunning because when I was a child long ago I wondered how the chick manages without air while it’s alive and breaking out of the shell. Magic? Nope, just Mother Nature’s engineering.

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