# Tag Info

52

The practice in the first half of the 20th century was to wrap wire in cotton cloth, resulting in something like a shoelace from https://www.vycombe-arts.co.uk/onlineshop/prod_3699705-Double-Cotton-Covered-Copper-Wire-Reels.html Alternately, pass your wire through wood resin, which will leave a fine insulating layer over your wire, good enough for low ...

51

Ok, so you say 'Harmonic Orbits', but actual Space-Talking-Dudes call that 'orbital resonance', and it's the solution to your problem. We've got an example of something ALMOST exactly like what you're talking about right here in our own solar system with Pluto and Neptune. As puppetsock rightly points out, their orbits don't actually intersect because of ...

42

The bullet will not go far It depends somewhat on the cross-section of the antimatter bullet. Let's assume that the bullet is slightly under 10mm in diameter, giving it a cross-section of 0.0000762 square metres. Passing through 1000m of air it will encounter head-on 0.0762 cubic metres of air, which conveniently is 3 moles. The molar mass of dry air is ...

37

Beeswax Expensive mind you, anything food related is, and you're cutting into the candle supplies of the wealthy, but beeswax is a good insulator, easy to work, and available in almost any historical period. Not suited for high temperature use. Cloth Also available in almost any period, though harder to work with for these purposes most cloths are ...

33

I have done this. I have an interest in old technology and I recreate crystal radios, telegraphs and mechanical television. When winding the solenoid you can seperate the windings by winding thread of similar diameter alternately with the wire (I used waxed sailmakers' thread). Once you get to the end of the coil former wrap a layer of paper (I used wax ...

30

You should have a look at Janus and Epimetheus. They are two moons of Saturn that exchange orbits every once in a while. This setup is probably not stable for more than a few billion years but it might do for what you want. Epimetheus orbits closer to Saturn, so has a shorter orbital period and eventually approached Janus from behind. As they get ...

24

NASA recently discovered a very interesting resonant pair in two moons of Neptune, Naiad and Thalassa. Their orbits (nearly <2000km) intersect and have periods of 7 and 7.5hrs respectively. Even though they are quite close at nearest pass (<4000km) they never actually collide because of this ”unprecedented” 69:73 resonance. This resonance was ...

18

There's actually a (beyond minuscule) loss of mass when fuel is burned. Your figures aren't much off for gasoline -- the extra mass comes from oxygen in the air. To oversimplify, let's assume gasoline is pure octane, C8H18 (molecular weight 114). To fully combust, it'll need 25 oxygen atoms (two for each carbon, and one for each pair of hydrogen), ...

17

Make the antimatter charged and use a magnetic bottle to keep it contained. It will reach its target without touching matter. On impact, the magnetic bottle mechanism breaks and the antimatter escapes. The bullet may be a little bulky, but some hand waving miniturizations should get it small enough to fire out of a weapon. Depending on the size, you may ...

16

You have copper wire. You need a thin insulating layer so that one winding does not contact the adjacent winding. This is easy. Assuming you can produce the copper wire, you need to oxidize it in an acid solution. This will produce a green oxide layer which is insulating. Wind the green corroded wire with no overlap on each layer. Put a layer of silk ...

14

Lacquer is an alternative. It comes in many thicknesses. It's not too expensive. It can be painted on then heat cured. There are many different types that can stand up to a variety of challenges such as wear, heat, cold, even limited bending.

12

Enamel Thin copper wires--like those used in inductors, transformers, motors, etc.--are enamelled. This is known in the modern world as magnet wire. Surely, you would prefer enamelled wire for your solenoid bobbin. We know that enamelled objects existed as early as the 13th century BCE. A concise history of enamel.

12

Let's say the bullet is a standard .308 Winchester round with a diameter of 7.85mm which means the bullet is encountering: $\pi * 3.925^2 * 1000 = 48,400$ cubic mm of air. The density of air at 20 degrees C is $1.2 KG / m^3$ which means the bullet is encountering around $0.058$ grams of air per meter of its flight path. Via $E=MC^2$, a total of 0.116 ...

9

The bullet will only work as intended if flying through high vacuum. In atmosphere, it would be necessary to evacuate its path, or at least a portion of its path directly in front of the bullet. Surprisingly, this might be possible: If an intense laser is fired in the bullet's path, it will heat and ionize the air; this alone will make it less dense, and ...

9

Lets first think about how much energy this needs. You've asked for spurious precision, but I'll save that til the end because no-one wants to see all the tedious decimal places in the workings (and if they do, they can repeat the process themselves). You want an orbit with a period of precisely 365 days, each 24 hours long. Via Kepler's third law, we can ...

7

Think Trees Gutta Percha , Latex , and Amber are reasonable insulators. Wrap the wires in various tree saps, and dry the covering over fire. Don't dry all the way, nor burn it, or it becomes inflexible. When working on the electronics, use dry clean wooden tools to avoid sparks and conduction.

6

Take assorted hydrocarbons from the gasoline. As the name suggests, they consist mostly of carbon and hydrogen, and by weight they are mostly carbon. Burn it, and one $C$ (carbon) atom bonds with two $O$ (oxygen) atoms from the air, forming $CO_2$. Each $O$ atom is about 1.33 times the weight of a $C$ atom, which means each $CO_2$ is only 27% carbon by ...

6

TL;DR: maybe. Orbital stability is pretty borderline, and some fairly unlikely circumstances have to arise to produce something that looks like maybe it will fit your needs. Tidal effects and orbital resonances will mess with the figures below, so they're only approximate Lets start with a star the size of the sun, putting the orbit of the planet at 1AU. We ...

6

TL;DR: Pretty unlikely. The objects are small (and hence faint), there aren't very many of them (astronomically speaking) and they're moving very fast so there isn't much time to spot them. Even if you knew they were coming, it might be tricky to catch a glimpse of them with today's technology. Basically, it would depend more on luck than judgement. If a ...

5

Paper? Paper may not have been invented (or be readily available) yet, but it can be made with available tools and materials. Paper is used as an insulator in our time, so could work for you too - it's a good insulator and it provides physical separation. It does require you keep it dry though - but you could coat your work in wax when finished if moisture ...

5

This article might be of interest. It turns out energy expenditure is as much a factor of air temperature as anything else. Figure three seems to be pertinent to your question. As it becomes a matter of simple mathematics to convert from their units to yours, I leave that to you!

5

Your villain is just going to commit a very elaborate and probably expensive suicide, and his target will be dead as a collateral effect. A magnetic field is effective at keeping away only moving charges. Most of the matter we have at sea level is in neutral state, including air, hands of whoever is loading that gun, the gun itself and the building where ...

5

No, nanoparticles will not retain the magnetic properties of the bulk material, as they will lose their constructive force without being physically locked to the same polarity with regards to each other.

4

Let's start the estimation with the drag: $$F_D = \frac{1}{2}\rho v^2 C_D A$$ Where $C_D A$ is going to be your form factor, depends on your drone design. Here are some example $C_D$ values $\rho$ is the air density. Here are some values, depending on temperature. If you increase the pressure to say 2x, the density also increases 2x. v is the velocity If ...

4

Not mentioned yet, but leather is also a good insulator. So there are plenty of options, most likely you'd want a combination of them for optimal effect of course, and to reduce the mess (resin gets sticky, so wrap the resin coated cable in cloth and wrap that in leather because the cloth is vulnerable to mechanical damage for example).

4

Mentioned before leather. Intestines (small-large) best leather for a wire coating. Already a tube just pull it tight and let it dry. Smaller animals smaller tube.

4

Explosives on the Earth's surface, no matter their power level (short of ejecting significant chunks of the crust) will never change the Earth's rotation rate or orbit. Nor will a reaction drive of any kind -- with the exception that if its exhaust, after exiting the atmosphere, is still above Earth's escape speed, some tiny fraction of its thrust will act ...

4

I think I can now answer my own question, having come across some decent references I hadn't found before asking it. I found the equation for the gravitational strain $h$ - the proportional change in length of an object due to gravitational waves from a mass $M$: $$h \approx {{GM} \over c^2} \times {1 \over r} \times {v^2 \over c^2}$$ (Source of formula) ...

4

It all depends on the accuracy and resolution of your simulation. Ultimately it’s not possible to create a perfect model of a pathogen due to the uncertainty principle operating at the lowest level of resolution in any model. That said an enormous amount can be learnt from simulations at all scales depending on what you are interested in. The secret is in ...

3

Pitch and cloth or paper. the first widely used insulated wire was insulated with asphalt (pitch) soaked cloth. both materials are available in a medieval setting. pitch is widely used by shipbuilders and a dozen other trades and cloth is a bit expensive but not prohibitively so especially for how little you need. Cotton cloth is expensive but nearly and ...

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