T&L Publications

You know what else is very interesting: Darwin had no idea about these tiny complex systems when he first came up with his theory. He looked at the whole and came up with a theory to explain that. Could he have been such a good guesser that his theory also applies to very small, tiny things like th...

I believe the "all parts must have been created at the same time" part for the flagella "motor" has been pretty well disproved. The various parts (proteins) are all very similar to other proteins with other functions. That implies that the various parts (or precursors to the vari...

Have you searched for just the part number without "schematic" (or similar words)? Often you can find the exact problem on the exact set. I've had luck finding things like how to fix bad vertical drive on a 15 year old set with details all they way down to which caps and which chip to repl...

Use current through a photocell to turn on a small motor. The motor must perform the next step Is that the exact wording of the challenge? Or do you just have to use a photocell + motor to do the next step? Could the photocell be used to stop an already running motor? That might be easier since you...

the hydrogen peroxide is the oxidizing catalyst Actually, it is the oxidizing agent and not a catalyst. The peroxide is consumed during the reaction, a catalyst is not consumed. Peroxide is a stronger oxidizing agent than oxygen (O2). Both are strong enough oxidizing agents to "rust" copp...

The heat of dilution for 30% H2O2 is pretty small, only about 0.2Kcal/mol. For 30% HCl it's more than ten times bigger at 2.7kcal/mol. So you need to add the HCl to the H2O2. http://www.h2o2.com/intro/properties/thermodynamic.html http://www.jsia.gr.jp/data/handling_02e.pdf For this particular etcha...

Always add the acid to the water . 30% HCl is pretty concentrated acid and will generate a fair amount of heat when mixed with water. The hydrogen peroxide is probably 3% so that basically water from a mixing standpoint. Any source that says to add the peroxide to the acid is wrong. Add the acid sl...

They work just fine, especially in a car environment where "fidelity" is really not all that important. You can also get corded versions that plug into the ear phone jack of your MP3 player then the cassette end goes into the car's player. They work fine as well. The fidelity is about the ...

As to ignition coils - The max output voltage read is not a practical test. First off, if unloaded, they may quite possibbly arc over and break down internally from abnormally hi voltage. One of the funniest kicks I get is to see JC Whitney, e.g. advertising 40 + KV coils. A normal spark plug will ...

Viewing the vibrating string with a strobing LED is certainly good for teaching people how a string instrument works. And how to visualize something that is moving periodically but too fast for the unaided eye to see. I wonder, what is the on / off time for a typical LED? Seems to me that that is go...

Those little igniters typically generate voltage spikes in the range of a few KV up to perhaps 10KV. If the gap(s) is(are) too big it won't work. You can try shortening the width of the gaps and see if that works. Gaps will also work better if one or both of the electrodes are sharp since spark's wi...

The only problem is that an electron isn't a particle. At least not when it is present in a conductor. It's a wave function. It doesn't exist at any particular place. "Drift velocity" requires the electron is located at a particular place at a particular time. This is an artifical construc...

IIRC, that method of calculating isn't correct. The speed of current through a conductor is basically the speed of light in that material. The electric field propagates at the speed of light. To get an electron "off the end of the wire" you push an electron onto the other end, the field pr...

Don't geiger counters count actual high energy particle impacts with the counter's detector? What about the person holding the geiger counter and background radiation? Certainly we have high energy particles zooming through our bodies all the time. Apparently there must be a safe limit, with some d...

An Electron-Volt is a pretty tiny hunk of energy! 100 million Electron-Volts wouldn't even tickle your tongue. But it may well cause cancer of your tongue. Like haklesup said, it depends on your point of view. 100 million Electron-Volts is about the energy of a single subatomic particle ejected fro...