Mexican student creates an acoustic fire extinguisher to put out fire in seconds

> he called oxygen the fuel for the fire... it's not the fuel for the fire

I think you're correct here, from chemistry definitions oxygen is not fuel, because breaking its bond consumes energy rather than releasing it. However, I don't think the host is trying to give perfectly precise chemistry definitions here, he's trying to explain how fire burns, and calling oxygen 'fuel' makes it clear to his audience that oxygen is required for combustion. I think your objection here is similar to objecting that voters in the US elect electors rather than candidates -- it's correct, but not necessary if you're explaining the concept of democracy.

> the port actually decreases the efficiency of the speaker by letting the negative bass note sine waves cancel out the positive sine waves from the front of the speaker, but this is done to tone down the "boominess" of the speaker at its resonant frequency, thus making the speaker more "neutral" sounding

I don't know much about bass reflex speakers, but I read the wikipedia page in decent depth, and it appears to me that you are wrong, or perhaps using a different definition than the field itself uses. From the wiki page: "This port enables the sound from the rear side of the diaphragm to increase the efficiency of the system at low frequencies as compared to a typical sealed- or closed-box loudspeaker or an infinite baffle mounting... Depending on the exact relationship between driver parameters, the enclosure volume (and filling if any), and the tube cross-section and length, the efficiency can be substantially improved over the performance of a similarly sized sealed-box enclosure." [0]. I bet I can see where your disagreement comes from though -- I think you're arguing that adding the reflex speaker cancels some of the power going through the main speaker, and therefore must result in decreased total_power_out/total_power_in (forgive me if I misunderstand). This is a sensible way to define efficiency, and I think you're correct that total_power_out is strictly decreased. However, there are also other sensible ways to define efficiency, eg, instead of total_power_out you might care about the perceptually-weakest frequency the speaker generates, to ensure the sound is "balanced" to a human ear. You might then define efficiency as num_spectral_bins*min_weighted_spectral_power_out/total_power_in. I have some experience optimizing perceived smoothness, and we used a metric very similar to this. Without fully knowing what you mean or what he means, I think you're disagreeing over terms, not correctness.

> but in any case, what he says about the "bulk" movement of air (he should probably call it net, i mean all air is bulk by nature) there is no way that the speaker pumping air in and out of the cavity could turn into net movement in one direction... the air coming out was directionally focused from the cone? and sucking back in was amorphous and somehow not detected by his device?

I think you're agreeing with him here, his explanation matches yours. We can break a full period of oscillation into two sections: a high pressure section (the air molecules being pushed away from the speaker), and a low pressure section (air being pulled back). The high pressure section travels _coherently_ through the air cannon, mostly moving air molecules in a single direction (as you say, it is "directionally focused from the cone"). The low pressure segment pulls air back into the air cannon, but it is _not_ coherent (as you say, it is "amorphous"). During the low section, molecules can flow towards the air cannon from the side of the cannon; they do not have to come from directly in front of the air cannon. If you rewatch that section I think you'll see you're not disagreeing with him. To be fair, more drawings would help communicate it more clearly. You're correct that if you draw your observation box big enough, there can be no net movement from something wiggling back and forth, but I think he's drawing his observation box over the fire. If you look at that system (the air above the fire), you will see net movement.

[0] https://en.wikipedia.org/wiki/Bass_reflex

[1] https://worldpopulationreview.com/state-rankings/average-iq-...