The number one thing on my son's Christmas list this year is a big book of science. He's not talking about a particular book, he just wants to look things up ten times a day. I tried searching on amazon, but somehow Harry Potter kept coming up (we already own all four). He's 11 and his recent interests have been to make a hover board like the one in "Back to the Future 2" out of six vacuum cleaner engines (he researched vacuums on the internet for a month) and now he seems to be letting that idea go in favor of a sort of hang glider. We go through a fair amount of vinegar and baking soda because mixing it is just too fun. It seems like he would eat up Bill Nye the Science Guy right about now, but his show doesn't seem to be around anymore. Anyhoo ----- any suggestions on a book?
Oh yeah, he asked me the other day how magnets were made for compasses before there was electricity. I told him I wasn't sure, but since electricity is what is used today, maybe lightning hitting a piece of iron would do the trick and then somebody would just have to discover that piece of iron. Was I close?
Was I close? I don't recall that being a primary source of natural magnets, but it seems like it could work. I believe the main natural source is iron-containing ores. Long ago when they were molten, the atoms were freer to move about, and since they were subjected to the Earth's magnetic field, they tended to orient themselves a certain way in response. (Much like a bunch of little compasses.) As the lava cooled, the atoms got locked in these configurations. So now when you pick up a piece of such ore, you've got a natural magnet. Pretty weak compared to what we can induce with electricity, but still detectable. (Float a lodestone on a piece of cork, and you can see it tend to orient itself with the earth's magnetic field.) It was also possible to create manmade magnets without electricity. Take an iron rod, point it north, and hit it hard with a hammer along the axis. The vibrations temporarily free up some of the atoms, a little - and they have an opportunity to reorient themselves a bit, which again they'll tend to do according to the earth's magnetic field. So when the vibrations die down, the reoriented atoms are locked into their new positions. And again, you've got a magnet. Pretty weak - but you can improve the process by heating the rod, and using multiple strikes. And if you've already got other magnets, you can create a stronger magnetic field than that provided by the earth, which will make your next magnet even stronger... [ December 12, 2002: Message edited by: Jim Yingst ]
Talking about magnets: I gave my kid a compass a few weeks back. The red end now points SOUTH. That's my boy! How on earth did he do that? -Barry
Joined: Jan 30, 2000
How on earth did he do that? Perhaps using one or more of
a powerful electromagnet
a very hot oven
a red felt-tip marker
Joined: Aug 03, 2002
Well, the compass is a plastic sealed liquid orienteering compass. So he did not use a hammer because there are no fractures, the plastic would melt in an oven, and the damping liquid is still in the housing, so he did not use a felt tip. So it's got to be the loud speakers or the television/computer screen. Which end of a television is South? -B
Joined: Aug 03, 2002
Still on compasses: Another interesting phenomenon is obtained after shuffling around the apartment with wooly socks on. Take the compass in one hand, and with one finger of the other hand make a small circular motion just above the compass. The compass needle follows the finger around the circle, and reverses direction when the finger reverses direction. Nice example of moving charges generating magnetic fields - or for convincing Mum that you've got Harry Potter's power. -B
The how stuff works is very cool. I mentioned the same thing to a scientist friend and he said to look for "Van Nostrands Scientific Encyclopedia" - two volumes. Apparently it has the authoritative word on all that is scientific. Anybody familiar with it? Compasses: I found out that compasses don't always work well around my house because the ground is rich in uranium.
Joined: Jan 30, 2000
I found out that compasses don't always work well around my house because the ground is rich in uranium. Errr... I hope that's the only thing that doesn't work well as a result... [ December 13, 2002: Message edited by: Jim Yingst ]
Paul: I cannot let this question pass without my comments (Sorry for the delayed response) When I was 12 I asked my parents for a TELESCOPE. I already had gotten the chemistry and biology kits/sets from GILBERT Co. The telescope opened a new view of the Universe (even at that age) for me. One thing is looking at static pictures of things... Another is seeing the:
moons of Jupiter
rings of Saturn
phases of Venus
phases of Mercury
craters of the Moon "up close"
all this, as it is happening at the moment in real time (OK; minutes before but I digress... ) I went off to graduate #1 in Physics from the Univ. of PR much later.
Tony Alicea Senior Java Web Application Developer, SCPJ2, SCWCD
Originally posted by Jim Yingst: It was also possible to create manmade magnets without electricity. Take an iron rod, point it north, and hit it hard with a hammer along the axis. The vibrations temporarily free up some of the atoms, a little - and they have an opportunity to reorient themselves a bit, ...
What is being shown at Primary School and then at high one being explained. McGyver used to save himself making magnets on-the-fly in that way.
Originally posted by Jim Yingst: I believe the main natural source is iron-containing ores.
They are called magnetic anomalies. Magnets are quite crazy in those places as well as over any big metal deposits even not natural. I recall that electromagnetic cranes do magnet metals only as far as there is electricity. The reason is very simple you cannot have strong (and controllable) magnetic field from "natural" magnets.