The high school that I attended, less than a decade ago, was relatively highly regarded. Within the district, it was considered one of the two “best” schools … although I will add that this was a rural district, somewhat underfunded, and a place where “bad” teachers sometimes went to disappear after being shuffled out of city schools.

There were a few teachers who stood out as particularly bad at their jobs, but there’s one who illustrates my point excellently, so I’ll focus on him: the biology teacher.

This biology teacher was considered incredibly smart. He did research work in the summers, had an MA, published papers. But his particular field was plants: specifically, the reproductive systems of moss plants. And we spent the better part of two years worth of biology classes studying this subject, and this subject alone. The curriculum was given the barest glance — we spent only three classes on human biology — while his particular obsession was pursued. We were infuriated. My passion for zoology was completely skimmed over (we never got to do so much as dissect a frog), while my best friend (an aspiring doctor, who did go on to work in the medical field) raged at the lack of relevant material. But the teacher was lauded for providing us with long-term projects that included so much hands-on material. He was acclaimed. The board loved him and held him up as an example of “non-traditional” teaching methods being used to great success. He certainly had a deep understanding of his subject matter. But his obsession turned people away from science in droves. After one year of looking at moss under microscopes and cultivating it in jars and drawing pictures of spores and rhyzoids and archegonia and discussing haploid cells, most people never went back to take the advanced bio class. And without the advanced credit, no university course in a biology-related subject was possible.

It’s all well and good to say that science education has changed, that it’s moving forwards, that we’re not where we were 50 years ago, or even 20 years ago. But we’re not there yet. Students still aren’t getting “turned on” to science. So the problem remains a real one, and in many cases it DOES come down to teachers who simply don’t know how to teach their subject.

Gravity is a force. A force is an *interaction* between objects, not something that objects “have”. Think of it like a handshake-an interaction between people: you can interact with someone by shaking hands – you don’t, however, “have” handshakes stored up just waiting to be used on someone.

Sometimes I feel like I have handshakes stored up but yes, good point, I get that. Good point.

Jupiter and Saturn would exert less gravitational force on their moons if their atmospheres were stripped away; it is possible the moons would no longer be held in orbit.

That’s what I was thinking.

Interesting, and that may well be. The idea that some of this was children’s armor (for the growing noble) was told to be my the curator of an armor museum so I’m not going to throw that idea out yet, but the plate-placement issue seems to be a good idea as well.

Burg: that the earth “has” gravity

But wait … the Earth still has gravity, right? Or did they change that!

Gravity is a force. A force is an *interaction* between objects, not something that objects “have”. Think of it like a handshake-an interaction between people: you can interact with someone by shaking hands – you don’t, however, “have” handshakes stored up just waiting to be used on someone.

Is air affected by gravity? Yes. As you said, it’s made up of stuff and stuff has mass, and mass interacts with other mass through the gravitational force. Earth has enough mass to exert a large-enough force on molecules of air (N2, O2, etc) to keep them hanging around: our atmosphere. The moon does not, and so has no atmosphere. Though it also depends on the mass of the molecule: even on Earth, helium just floats off into space, pushed upward by the buoyant forces from the larger atmospheric molecules.

Jupiter and Saturn would exert less gravitational force on their moons if their atmospheres were stripped away; it is possible the moons would no longer be held in orbit.

Asserting that things “have” or “carry” force is fairly common. I believe Rhett Alain has written about ESPN Sport Science and others doing just that (sorry, I don’t know how to link to his blog); probably more eloquently than I can.

Also, “air” is atmosphere (as we usually think of it). How much less gravity would Jupiter or Saturn have if you totally removed the atmospheres from the planets?

I have an advanced degree in Physics, and currently teach at the college level — I’m not surprised the teacher didn’t know how to answer that question. It’s potentially a multi-faceted question, and depending on the age/grade level of the student could be quite difficult to answer in a satisfactory way.

Though, the quick, “lets convey no extra information or understanding to the student” answer would be “no”.