A scale works by compressing something and measuring how much that thing is compressed. In an analogue scale, that's usually a spring that turns a dial when compressed. In a digital scale, its usually a wire with a current being run through it - when the wire is compressed, the wire's resistance increases so the amount of current flowing decreases.

When you put a scale on a hard surface, there is nothing under the scale to compress, so 100% of the compression is focused on whatever inside the scale is measuring compression.

When you put a scale on a soft surface, like a carpet, the carpet functions as a continuation of the measuring surface inside of the scale. IE, some of the compressive force being applied to the scale is instead applied to the carpet, reducing the amount of force on the internal components of the scale.

Its an extremely rare disease that he almost certainly does not have, given that people who legitimately do will have distinct personalities with their own memories, and no cross-over between the two. IE, each personality has no memory of what its body did while the other personality was in control.

The far more likely explanation for your friend's issues are that he has found that pretending to have a serious mental illness draws attention to himself, and he enjoys that attention.

Draino used to be made out of lye, which would damage metal pipes and the rubber seals in pvc pipes with normal use. But that's kind of ancient history.

For the past few decades Draino has been made out of bleach. It will dissolve low density clogs, like hair, but isn't particularly effective against solid clogs caused by things like fat.

Its not particularly caustic, so there isn't much of a risk to the plumber's health if they're wearing gloves. But it will dissolve some of whatever was clogging the drain, which usually turns it into a sort of chlorinated poop water. The fact that there will still be some bleach in it also means that if it spills it can ruin/discolor the stuff that it spills onto. Both of which makes it more difficult to work with than just dirty water.

Basically, Draino works on the things that plumbers don't normally get called out for and doesn't work on the things that they do get called out for. If you use Draino on a tough clog, you haven't accomplished much other than to make the repair miserable for the plumber, who has to clean it up afterwards.

Windows don't do very well in unheated, unairconditioned buildings. Excessive cold (below freezing) or heat (above 100 degrees) both cause the glass to weaken over time. After a few years, the windows will begin to shatter on their own.

This isn't a problem if you're heating or cooling the building, since the windows will never get cold/hot enough to begin weakening. But it is a problem when no one is paying to run that stuff.

Cold poses another problem for windows - if the temperature inside of the building drops below the dew point, then condensation will form on the windows and drip down onto the interior of the structure, causing mold or rot.

Then there's the fact that human beings exist. Teenagers and college kids like breaking windows in buildings they know are abandoned. Squatters and thieves can also take advantage of the ease of entry/repair to gain access to the interior of the building. Getting through plywood is a lot more difficult and pretty clearly indicates to the police that anyone who is inside of the building is not supposed to be in there.

Wood frame buildings are viable because of drywall and fiberglass insulation. Drywall is cheap and essentially hangs from the wood frame, while the fiberglass insulation is lightweight, thin, and a better insulator than pretty much anything else.

Without those two things, you can't build a wood frame building - the entire building needs to be made out of wood then sealed with something like tar, which isn't a particularly good insulator. In a world without drywall or fiberglass insulation, brick is both cheaper than wood and a better insulating material.

Many European buildings date back to a time before drywall and fiberglass insulation existed. Northern and Western Europe, where you tend to see the most brick buildings, also don't suffer from natural disasters like Earthquakes or hurricanes. So even though brick buildings aren't particularly survivable in much of the world, they are survivable in certain parts of Europe.

That being said, new construction using brick more or less does not exist in wealthy countries. The vast, vast majority of "brick" is actually textured vinyl siding. It looks and feels like brick, but its basically just plastic wallpaper that's been glued to whatever is underneath. Where brick is used, its actually reinforced brickwork where a steel skeleton is what's providing structural strength and the brick is basically just decorative.

Brick is really only used as a construction material in very poor countries where the cost of labor is very low. The most expensive part of unreinforced brickwork is that its labor intensive to lay - the brick itself is cheap to make and doesn't require any sort of skilled labor at any point in the brick making/laying process. If the cost of labor in your country is extremely low, then so is the cost of brick construction.

Ice floats because water gets less dense when it freezes. But that isn't true for salt water - salt water behaves like most other substances and increases in density as it freezes. This means that when the ocean gets near freezing, cold, salty water sinks leaving warmer, less salty water near the surface.

Sea ice will only form when the temperature has dropped to a few degrees below freezing for an extended period of time because that allows for the salinity at the surface to drop to the point where ice with that level of salinity has slightly positive buoyancy (it floats). The level of salinity where ice will float is similar to the level of salinity in brackish waters in the ocean near the outflows of major rivers. Ice with that level of salinity is still too salty to be called fresh water, even though it is less salty than the ocean.

But there's another process that occurs - because salt makes it harder for water to freeze, the water that freezes first is formed of microscopic pockets of water that just happens to be salt free. Those initial, salt free ice crystals grow by "absorbing" water molecules from the surrounding ocean. IE, molecules of salt won't stick to those initial ice crystals, but other molecules of water will.

As the salt free ice crystals continue growing, they begin to trap microscopic pockets of very high salinity water inside of them. As a result, new sea ice is made up of crystals of pure, salt free ice water with millions of tiny pockets of extremely salty water trapped inside. Given how small the salt water pockets are, the ice will still appear to have the same brackish salinity as the sea water it froze from to something the size of a human.

But those pockets of salt water don't remain static. The salt will "melt" through the fresh ice below it, eventually melting all the way back into the ocean. This leaves behind a tiny pocket of water free air. The longer a piece of sea ice exists, the more opportunity the salt water inside of it has had to melt out. After about a year, all of the salt inside of the ice will have melted out and what you're left with is a hunk of pure frozen water.

Carburetors and older/cheaper fuel injection systems use a mechanical switch to determine how much fuel goes into the engine. This switch is usually controlled by a float that is quite literally floating on some of the gas that is entering the engine. If too much gas is entering the engine, the float rises and pushes the switch closed. When the level of gasoline drops, the float sinks to allow more in.

The buoyancy of that switch is calibrated against the amount of gas that the fuel pump is delivering to the engine - which will be a fixed value. IE, if the fuel pump is delivering 1 psi of fuel to the engine, the float will be set to press on the switch with 1 psi of pressure when the fuel supply needs to be cut off.

Pumping fuel into your car can increase the amount of pressure in the system, which can increase the amount of pressure coming out of the fuel pump - particularly when the tank is near full.

So imagine that your tank filling up causes a pressure surge and that 1 psi of fuel normally coming out of the fuel pump briefly spikes to 5 psi. That's going to mean that the switch in your carburetor/fuel injector doesn't close and more fuel keeps going in even though the engine is full. That could potentially flood your engine.

A flooded engine can be anything from a minor inconvenience to something that burns out your starter motor.

In the modern world, nobody listens to a speech from start to finish. At best, the vast majority of people will get a handful of ten to fifteen second long clips from their favorite news and/or social media channel. So that's how modern speeches are written - they tend to be very short and are essentially just brief soundbites that have been stuck together in such a way to make it easy for other people to edit them down into clips.

Historical speeches were much longer - Hitler's speeches would often go on for >2 hours and that wasn't unusual among politicians that were good at giving speeches.

Historical speeches are often exhaustive explanations of what the speaker thinks is the problem, how they intend to solve the problem, and why other proposed solutions to the problem are inferior to theirs. While you can often pull brief snippets out of those speeches - such as "the only thing to fear is fear itself" - stuff like that often doesn't translate well from foreign languages.

Making sense of historical, foreign language speeches requires you to listen to the whole thing, which is probably several hours longer than the documentary you're watching.