| Author | Message | ||
     Ben |
Is their another way to create some kind of rotating device? A motor that doesn't depend on magnets and eltromagnets? I'm trying to construct a more effecient way of rotating an axle in a small robot | ||
| Simon Quellen Field (Sfield) |
Do a Google search for "mousetrap cars". Wind-up toys are another source of power not to be taken lightly. For a small device, steam turbines are probably out of the question, but compressed CO2 into a turbine or model steam engine can be done. Rubber bands are also quite effective. | ||
| Anonymous |
hi guys- i'm trying to construct a larger, demo model of the "drinking bird". some dumb questions: i need to vacuum seal a glass seam. you say in your book that indium will stick to (ie, seal?) glass. will an alloy containing a significant amt of indium, like field's metal, also solder to glass or does the indium have relatively pure? as you say, raw indium is way expensive. i'm willing to try indium as a sealer, mainly out of desperation. i'm trying to construct the bird using methylene chloride, pretty nasty stuff. it destroys everything i've tried so far to use as a sealer. seems to eat anything except glass and metal - i've tried silicones, rubber, various epoxies, everything i can think of. can i add something to gallium to raise the melting pt and use that instead? how will gallium react to the meth/chlor? i'm a little nervous because my meth/chlor supplier says i can't store it in an aluminum container, due to potential violent reaction, implying that i have to be careful about what kind of metal i expose to the chemical. i hope to avoid any exploding birds.  thanks much for your advice | ||
| Simon Quellen Field (Sfield) |
Gallium and indium will probably react with the chlorine in the solvent. Tin and steel will be OK. I was going to use copper tubing and ordinary solder in a similar project, where I did not need the device to be transparent. I was going to build six of them in a wheel, powered by sunlight falling on half the wheel, with the other half shaded. See if it dissolves PVC or CPVC. Teflon will probably be OK. Methylene chloride is nice because of its low boiling point and nice vapor pressure. However, water or alcohol will also work, you just need a higher temperature. | ||
| lysdexia Unregistered guest |
Minto's wheel? | ||
| Twors (Twors) Junior Member Username: Twors Post Number: 10 Registered: 7-2006 |
Hey I don't understand conservation of energy. Why does a lever obviously do more work than just my bare hand? What is the source of the extra energy input if the output is the same as the input? oh and do same size gears together act like a bunch of levers and so provide more torque than one of them by itself? | ||
| Simon Quellen Field (Sfield) Senior Member Username: Sfield Post Number: 1543 Registered: 12-2004 |
Apparently, not many do. You can lift a heavy thing a small distance, or a light thing a long distance, and use the same energy. The lever lets you make that trade-off. To lift fifty pounds up a foot, you push down with a force of ten pounds for a distance of 5 feet. |
