58 votes
Accepted

Are stainless steel railway tracks worth it?

Stainless steel is about four to five times more expensive than ordinary steel. This means that even in a perfect world where companies or States could plan for a time horizon of a century or more for ...
AlexP's user avatar
  • 87.5k
44 votes

Is it possible to design a bottle that can always be "full"?

They just need a Spout Pouch We have already solved this problem for situations where we need to reliably contain liquids while still being able to access them, particularly spaceflight. You need to ...
Stephen's user avatar
  • 8,444
40 votes

Is it possible to design a bottle that can always be "full"?

If you want a cheap and reusable solution, liquid ingredients can be stored in syringes. You can make them any size you want (see image below for a really big one sold in Walmart for about ten bucks). ...
The Square-Cube Law's user avatar
34 votes
Accepted

Is it possible to design a bottle that can always be "full"?

Drop 'marbles' of this special substance into the flask. Remove $1\: cm^3$, add a sphere $1.24\:cm$ in diameter. (Might that be combined with measuring? Throw a marble in, a measured amount overflows.)...
o.m.'s user avatar
  • 114k
32 votes

What is the longest bridge that a Bronze Age society could build across a bottomless chasm?

This is close to a duplicate of Building a bridge from one side. However, the limitation to the Bronze Age perhaps makes this a unique enough question. That question does make one point: somehow you ...
JBH's user avatar
  • 120k
28 votes

Is there any reason a society might use electric boilers and steam engines in their trains rather than electric motors?

For train locomotion, straight-electric is vastly superior to electrically-generated-steam in many circumstances. Electric locomotives are much lighter than comparable steam, making infrastructure ...
user535733's user avatar
  • 28.9k
25 votes

Is there any reason a society might use electric boilers and steam engines in their trains rather than electric motors?

Lack of magnetic theory. If you know about electricity but not about electromagnetism, using electricity to drive a heating element makes some sense. Generally, it would be surprising if someone ...
fectin's user avatar
  • 2,981
25 votes

Are stainless steel railway tracks worth it?

Stainless steel is TERRIBLE for train tracks. Especially if you are trying to use the most rust resistant grades. Expensive to produce Difficult to fabricate Stainless is difficult to machine compared ...
DKNguyen's user avatar
  • 10.9k
24 votes

Is it possible to design a bottle that can always be "full"?

The traditional solution with paint was to store it in a bladder tied with string, and squeeze out what you needed. This was replaced by the paint tube. American portrait painter John Goffe Rand, ...
Richard Kirk's user avatar
  • 7,565
24 votes

Would it be possible to make a brass/wind instrument with a jet engine as the source of airflow?

It's very possible, it has been done, and they don't have to be humongous! It depends a little bit on your definitions, but what you are looking for is a pulse jet engine. These work by detonating ...
EdvinW's user avatar
  • 3,110
23 votes
Accepted

How large would the LHC be if room-temperature superconductors were available?

The electromagnets of the Large Hadron Collider are superconducting. Yes, they need cooling with liquid helium. Yes, this increases the complexity of the machine and creates points of failure. Were ...
AlexP's user avatar
  • 87.5k
22 votes

Is it possible to design a bottle that can always be "full"?

I like the Spout Pouch idea, but it sounds like you might be looking for something rigid. If a metal cap threaded into the neck of a metal bottle works, then just use a cylinder that's threaded all ...
AeroSigma's user avatar
  • 501
22 votes

Could Mermaids Tear a Warship's Planking?

Seems a lot of work just to capture a ship which is now sinking. There's not much point asking them to surrender in a sinking ship unless you want them in boats and the ship at the bottom of the sea ...
Kilisi's user avatar
  • 26.2k
20 votes

How bullet resistant would a person be who is 80 times more durable than a regular human?

I find one reference to skin having a tensile strength of ~30 MPa. If it were 80x stronger, that would be 2400 MPa, which is in the same ballpark as kevlar with ~3600 MPa. As well as being weaker than ...
Starfish Prime's user avatar
19 votes

What is the longest bridge that a Bronze Age society could build across a bottomless chasm?

(Really a comment to JBH's answer but way too long) You need to find a stout tree on the far side of the chasm. Build a kite (fabric on a wooden cross is enough), take two cords and fasten them to ...
Loren Pechtel's user avatar
19 votes

Would it be possible to make a brass/wind instrument with a jet engine as the source of airflow?

Yes... but No Okay - bold statement here, definitely not hedging my bets... So - in terms of the basics - yes, an instrument with a constant flow of air could work. You might have some technical ...
TheDemonLord's user avatar
  • 21.9k
18 votes
Accepted

Is there any reason a society might use electric boilers and steam engines in their trains rather than electric motors?

I only provide this answer because no-one else seems to have covered the point that such things have existed in real life; see Wikipedia page on Electric-Steam Locomotives. The page notes that "...
user85471's user avatar
  • 296
18 votes

What is the longest bridge that a Bronze Age society could build across a bottomless chasm?

Incas lived practically in bronze age and they built rope bridges using grass fibers. https://en.wikipedia.org/wiki/Inca_rope_bridge The greatest bridges of this kind were in the Apurímac Canyon ...
Juraj's user avatar
  • 2,564
17 votes

Is there any reason a society might use electric boilers and steam engines in their trains rather than electric motors?

Nope, no conceivable reason. The conversion losses would be very bad It's not the boiler - that would enjoy 100% efficiency, after all. It's the monkeyworks. Classic steam locomotives run around 4-10%...
Harper - Reinstate Monica's user avatar
17 votes
Accepted

Feasibility of a 5000km tall orbital tower using active support

Not possible For every action, there is an opposite and equal reaction. The surface of your planet could not endure the reaction force of your active support system. All of the force you exert ...
Nosajimiki's user avatar
  • 89.2k
17 votes
Accepted

Could Mermaids Tear a Warship's Planking?

My take on this problem - discounting the problems of availability of metal tools to merfolk - is that there are going to be lots of problems with this approach and probably better ways to achieve ...
Monty Wild's user avatar
  • 59k
16 votes

Is it possible to design a bottle that can always be "full"?

Does the potion mix with oil? If not, then you can carry your potion in whatever bottle you happen to have, use as much of it as you like, and top up the bottle with oil which would prevent air from ...
ihaveideas's user avatar
  • 3,868
16 votes
Accepted

Can a device that causes memory loss be created with near-modern technology?

You could go with a technique called Trans-cranial Magnetic Stimulation or TMS. But you'd also have to 'play around' with the science a bit and assume a couple of breakthroughs in neuroscience that ...
Mon's user avatar
  • 16.1k
16 votes

How to recreate a "land" harp that can work in the deep sea?

Compare this video of "Under the Sea" performed underwater on a piano to a normal piano cover, especially the first 5 seconds of the song. The former version has these completely dead-quiet ...
E Tam's user avatar
  • 2,048
16 votes

Is this diesel gun concept feasible?

The problem with dieseling as a means of propelling a bullet is that the pre-ignition pressures involved are sufficient to move the bullet down the barrel without the fuel present. Air guns are ...
Monty Wild's user avatar
  • 59k
15 votes

Can I use the Peltier effect to cool down an underground city on Venus

Peltier coolers are what you do when you need something solid-state. Based on your comments, it sounds like you'd take any solution, but you just didn't know how to ask, so I'm going to suggest "...
Robert Rapplean's user avatar
15 votes
Accepted

Expanding a modular space-station for 100 years

Yes, via Ship of Theseus This is very easy to accomplish. Over time, as components are added and expanded, outdated or worn out components are replaced by their equivalents. If the station has been ...
Daniel B's user avatar
  • 19k
14 votes

Is there any reason a society might use electric boilers and steam engines in their trains rather than electric motors?

Nobody in Your World Has Created a Good Electric Motor Yet Perhaps nobody has invented an electric motor yet, or, if they have, they still have limitations that make them impractical or unsafe to use ...
Kal Madda's user avatar
  • 1,851
14 votes

Super broad gauge railway vs double wide/multi track railway

If he uses a pair of existing standard gauge tracks as a four-rail single track, he's going to hit a lot of problems: The most obvious is that the spacing between pairs of tracks has been managed for ...
John Dallman's user avatar
  • 23.9k
13 votes

Can You Make A Tiny Nuclear Reactor By Employing Supercritical Conditions For Brief Periods Of Time?

Theoretically you could, but it seems rather pointless. Going supercritical makes your fuel degrade quickly and unevenly. It's like trying to make rocket engine working on hydrogen and oxygen "...
D'Monlord's user avatar
  • 2,513

Only top scored, non community-wiki answers of a minimum length are eligible