Isaac Newton and Physics for Kids

This is a book for kids in middle elementary school to introduce them to Isaac Newton and basic mechanics. There is a brief review of it on Wired.

This year I asked Chicago Review for a review copy of their book Isaac Newton and Physics for Kids. Even though my kids are beyond the target age, I thought it might be a useful reference for our physics homeschool studies this year. (Tip to homeschooling parents: If you want to bone up quickly on a topic, try reading a high-quality middle-grade book. Most times you’ll get all the information you need to get started, without overwhelming amounts of detail.) What I found was an excellent biography on Newton that touched on his physics discoveries but didn’t really focus on them. Nonetheless, it is an excellent book for those who want to read about this eccentric and brilliant thinker.

Zz.

Newton and the Apple

It appears that the Royal Society has released documents regarding the fabled counter between Newton and the apple. I didn't put that statement in a more definite form because I have not been able yet to get to the Royal Society webpage that contains the scanned document. Either their webpage has been overwhelmed by all the publicity, or they have a server that sucks.

In any case, the conclusion seems to be consistent with the one I reported earlier of an account by William Stukeley.

Zz.

April 15, 1726: Apple Doesn't Fall Far From Newton

This is a rather interesting account of the fabled Newton's apple. It appears that on this day in 1726, Newton talked to William Stukeley on how he came up the idea of his gravitational law. That's when the apple came up, so to speak.

It was occasioned by the fall of an apple, as he sat in contemplative mood. Why should that apple always descend perpendicularly to the ground, thought he to himself. Why should it not go sideways or upwards, but constantly to the earth's centre.

Newton (like Ben Franklin and his kite more than a century later) may have indulged in some self-mythologizing here. Surely, the puzzle was not that things fell down rather than sideways. Isn't that what the concepts "fall" and "down" are about?

Newton's breakthrough was not that things fell down, but that the force that made them fall extended upward infinitely (reduced by the square of the distance), that the force exists between any two masses, and that the same force that makes an apple fall holds the moon and planets in their courses.

Still, it is almost definite that his inspiration did not come from an apple dropping onto his head. That is a myth.

Zz.

Seasons Greetings

Happy Holidays to everyone! If you are traveling, hope you have a safe and hassle-free trip, especially if you're in the areas affected by the nasty weather here in the US. With the new administration about to take office, let's hope that 2009 will be a better year for physical science funding even with the current economic problems.

If you are not going to celebrate the season for to religious reasons, then maybe you could celebrate it as part of the 10 Days of Newton. Isaac Newton was thought to have been born on Christmas Day under the Julian calendar.

All very jolly — but then, ’tis the season. Yet things are not so simple. It turns out that the date of Newton’s birthday is a little contentious. Newton was born in England on Christmas Day 1642 according to the Julian calendar — the calendar in use in England at the time. But by the 1640s, much of the rest of Europe was using the Gregorian calendar (the one in general use today); according to this calendar, Newton was born on Jan. 4, 1643.

Rather than bickering about whether Dec. 25 or Jan. 4 is the better date to observe Newton’s Birthday, I think we should embrace the discrepancy and have an extended festival. After all, the festival of Christmas properly continues for a further 12 days, until the feast of the Epiphany on Jan. 6. So the festival of Newton could begin on Christmas Day and then continue for an extra 10 days, representing the interval between the calendars.

So maybe we can add another "holiday" to this time of the year. :)

Zz.

Newton's Second Law Tested Even More!

You wouldn't think that there's any reason to continue testing one of the most widely-used theory in physics, would you? But people do still test F=ma, and this time, it has been tested up to 5 x 10^-14 m/s^2. Take that! It appears that this came out of a similar technique from the University of Washington that also verified the Newtonian gravitational laws up to the micrometer scale.

The report in the link listed a couple of reasons why we continue to test the range of validity of this law. The most important one is with regards to the issue of dark matter/dark energy, and the possible tie-in with the anomalous acceleration of the Pioneer spacecraft. So this test isn't just "for the fun of it".

More info and exact citation to the paper can be found here. A news review from Science can be found here.

Zz.