Science questions not worth a thread I: I'm a moron!

[peter grimes]

Or, rather than a powder & bonder, just a hot-melt polymer. That's how the MakerBot works.

A colleague of mine who does this was recently feature in Wired:
http://www.wired.com/design/2012/06/...s-on-broadway/

[PlutonianEmpire]

Ah, ok. Is there a possibility of the supplies required for the 3D printer to make stuff running out; such as on a long-haul deep space mission?

[Cutlass]

Of course. You can only use it as much as you have the feed stock for it. It's no different than any other type of production in that respect. You don't get something out of nothing. So the thing to do is to learn to recycle the material efficiently once you've used and no longer need a piece of it. The less waste material, the further your feedstock will go.

[madviking]

It'll probably chew up a huge amount of energy.

[PlutonianEmpire]

Originally Posted by Cutlass

Of course. You can only use it as much as you have the feed stock for it. It's no different than any other type of production in that respect. You don't get something out of nothing. So the thing to do is to learn to recycle the material efficiently once you've used and no longer need a piece of it. The less waste material, the further your feedstock will go.

Yeah, that's what I thought. Some of the articles on it seem to give the impression that supplies are infinite.

Thanks.

[Samez]

Rapid prototyping (3d printing and so on) is quite fun. It can also result in art like this:

For more art go here.
There are a few issues if you plan to use objects created by 3d printing under mechanical stresses. Due to the fact that they are made of layers there will always be some kind of boundary layers which will result in anisotropic mechanical properties. Also the types of materials which can be used for 3D printing is limited.
If you are interested in further information I could upload you a 300+ page pdf (~50 mb) with an overview of the different rapid prototyping/manufacturing methods. But be warned it's a bit chaotic due to our chaotic prof.

[_random_]

Why are objects in mirror so much closer than they appear?

[Mise]

Didn't someone already answer that one?

EDIT: In fact, you did, and have done at least 3 times now!

[contre]

Originally Posted by contre

As in the passenger-size mirror? I believe it's slightly concave (as opposed to the driver's side which is flat) and as such, it makes objects appear smaller. So in your driver's-side mirror an object 25 feet away looks X size, but in the passenger-side mirror, the same object at the same distance looks smaller. Your brain interprets that as further distance.

Originally Posted by contre

Ahem.

Ahem.

[peter grimes]

post-ception?

[_random_]

Oops. Sorry.

[contre]

Anyone know why objects in mirror so much closer than they appear?

[peter grimes]

Originally Posted by contre

Anyone know why objects in mirror so much closer than they appear?

In order for you to see an object in the mirror, light must reflect off its surface. The light then has to travel to the mirror, reflect off the silvered surface, enter your eye, interact with the rods & cones, then get processed by the gnomons in your brain. This happens pretty fast, but not instantaneously.

In that time, the object, bring in motion, has moved. So has the earth around the sun, the sun around the galaxy, etc. But the light corpuscles move on a straight line (Newton's Laws!), do yhr object will actually br closer than it appears.

Hope this helps!

[sanabas]

But if I'm moving away from the object, then won't it appear closer than it actually is, rather than be closer than it appears?

[Michkov]

How hail resistant are solar cells?

[contre]

A company that sells panels here in Ottawa offered me a job a while back. I turned it down since it was commission-based but part of the training covered this.

Depends on the panels. Tempered glass ones should survive direct hits from a 2.5cm hail storm. Direct hits are uncommon since hail storms are rarely blowing in from the south (the hail is going to hit your panel sideways, normally). If you live in Kansas where you get baseball sized hail, you'll probably want some of the cool flexible plastic ones. Even if they are damaged their performance doesn't get hurt much.

Most home insurance policies cover solar panels, actually. So even if broken by hail, they will be replaced.

[Meteor Man]

Hey guys, I've been getting conflicting reviews for this, so I'm going to ask it here.

I've been looking into creating a magnetic generator using neodymium permanent magnets, and have been getting many sites claiming that they work, other saying that they're impossible, and some youtube videos that seem to work.

I just want to know if a magnetic generator is actually viable.

Oh, and is this site legitimate? It's annoying as all hell, but from what I hear it may actually work.
(http://www.magnets4energy.com/?hopc2s=sale100)

[contre]

Quick tip: if you're looking at something that promises free energy, it is a scam. Nothing can give out more energy than you put into it unless there's a fuel source within it: a fusion reactor will output more energy than it takes to start it, but only through nuclear fusion of hydrogen into helium.

Devices using magnets to create free energy are purported to work based on a perpetual motion machine. Indeed, if you could create a perpetual motion machine, and you were to use a magnet in it that ran by some copper coils, you would have free energy. The catch is that perpetual motion machines violate everything we know about physics.

[sanabas]

Just look at the bonuses you get with it. Manuals for running your car on water & harvesting electricity from telephone lines.

Or read their FAQ: "Question: How is it possible to generate energy from nothing?
Answer: Magnetic Generators DOES NOT generate energy from nothing. The energy produced by a magnetic generator is gathered from the gravitational energy of earth itself. The proof of concept is simple; get 2 permanent magnets and put them next to each other with same sides facing - you will notice that the magnets push themselves apart. The force pushing the magnets is the gravitational force of earth which is channeled trough the permanent magnets. Therefore, NO energy is created from nothing, it simply uses the earth's gravitational force to rotate a shaft that will generate electricity. "

[Meteor Man]

The force pushing the magnets is the gravitational force of earth which is channeled trough the permanent magnets.

Well, THAT'S bull.

I was actually looking to create an overunity generator rather than a pure magnetic energy source. (Overunity: applying less energy into the generator than is produced.)