I use the dot multiplication symbol in units for clarity, so the abbreviation for meter-newtons would be [m⋅N], whereas millinewtons is [mN]. The dot can be hard to see sometimes, so it's probably better to stick with newton-meters [N⋅m].

Or we could just call it joules! [N⋅m] = [kg⋅m²/s²] = [J].

Bill Gates has his faults but the global vaccine and health initiatives funded by his wealth have saved far more lives than any other rich person's wealth and for that reason I give him a lot of latitude rather than blindly place him in a "billionaire=evil" bucket.

Cool. Today I learned that an automobile and a car are roughly equivalent in terms of weight and efficiency.

I remember as an undergrad going to my first research seminar. The student ended his presentation prematurely, or so it seemed. Someone asked, What were your results? Answer: We don't have any results yet. I've spent two years just trying to get the dumb machine to work properly. It was eye-opening.

I say in class, "The hydrogen really wants to bond with the chlorine - of course it doesn't really want anything because it has no feelings, but the laws of the universe work out just right so that it seems that the hydrogen really wants to do this."

I teach using both words with the understanding that they are not synonyms. A radial vector can be outward pointing or inward pointing, whereas a centripetal vector is always inward pointing (and I avoid the word "centrifugal" like the plaque, in intro classes).

"We see it moving away at just faster than light." This is misleading. The light that you are looking at from a distant galaxy is how the galaxy looked before it was moving away from you at greater than light speed. Light from a source that is moving away at v>c will never reach you.

That's fun. Note that with a strong enough handheld magnet, the diamagnetic response of non-ferromagnetic materials becomes significant, e.g. you can do this same demonstration with wood. So it doesn't necessarily prove that an object has a lot of iron.

youtu.be/gJeqriqRYYE?...

Does your university not have travel cards or procurement cards? You know, credit cards with your name on it but tied to the institution's accounts. Ask around because this may be available to you. Also, if requested, universities will often give advances to grad students/post docs for travel.

It depends on the type of tree. There is huge variability in trunk structure. Counterexamples that immediately come to mind are baobabs and pine trees.

I might be missing something here, but to determine the precision, you need multiple measurements and then you compare them to each other. It doesn't make sense to talk about the precision of a single measurement without referencing anything else.

Along these lines, I often have the students calculate the height from earth's surface to get a 50% reduction in weight. I think that it helps dispel the myth that gravity magically turns off just outside earth's atmosphere.

This is good news but keep in mind that inflation being down to normal levels does not mean that prices are down to pre-COVID levels. People whose salaries did not correspondingly increase along with the high inflation are still feeling the pinch of high prices from previous inflation.

I've seen this type of demonstration several times before but this is by far my favorite version so far!

Call me old-fashioned, but I still don't use GPS when driving (except for long trips to new places). I prefer memorizing maps and exploring. I'd rather know things then have a machine know them for me. Also, I think it's a little fun to get lost sometimes and explore until I'm not lost.