Yes, it also strikes me as somewhat a poor explanation for the observed phenomena. The flow of water at that speed is, more than likely, not laminar. The flow of water at the end of the nozzle is certainly not laminar and hence, Bernoulli's principle should not be applied here. I think the small stream of water out of the nozzle maintains its diameter for a while due to viscosity. Hence, this small stream impacts against the walls of the plastic hose until water can fill the entire diameter of the hose again. In the little space after the exiting of the nozzle, there must be empty spaces created by the small stream of water and evaporation might occur here, but it was not caused by the effects described by Bernoulli's equation, but due to effects associated with turbulent flow and viscosity.

​@@ozkroca9003 PLEASE let me know with a reply, if you follow this. You are close. I now see what is happening. . If you don't know what entrainment is, please look it up. It does have to do with viscosity. . Look closely at the zoom-in at time 1:05. . A drawing would help. . The Inside diameter {ID} of the nozzle is smaller than the hose ID. This leaves a blunt edge of that nozzle rim where the smaller stream of water exits into the wider hose. . There will be water right up against that blunt rim forming a "stationary" water ring around the exiting jet of water. . The exiting jet will entrain that ring of water, drawing it downward along with the jet. Think of it as friction, or a viscosity effect. The blunt rim PREVENTS more water from filling-in to the space immediately below the rim. . Because that water ring is drawn away from the blunt edge, that lowers the pressure in that 'ring'. . With low enough pressure it can vaporize the water as he correctly says, causing tiny bubbles of water vapor to form that gives it that cloudy look as there is much turbulence within that ring of what is now tiny bubbles. . So it is NOT simply the low pressure "created by high velocity". That is sadly an all too common misunderstanding of Bernoulli that I call "Bad Bernoulli". . The high speed jet AND this BLUNT EDGE geometry is a set of constraints that together, with entrainment, are the causes of the lowered pressure. . It takes ALL of that, NOT JUST SPEED.!.!.! . When he turns up the flow you can see the soft hose being drawn in more, as well. . WHEN the hose is not pushed on, that jet of water will draw AIR along with it on the outside of the jet. Entrainment works between fluid types. . This is the 'shower curtain effect'; it is why a shower draws the curtain inward - - water entraining the air around it. it IS the entrainment removing the fluid around the jet and you have some surface preventing the fluid from flowing back into that space to replace that sir, THEREFORE causing a lowered pressure. . It takes ALL of those constraints for this to happen. . The water jet OUT OF the nozzle would be AT ATMOSPHERIC PRSSURE if there was no hose and other surfaces preventing a free flow of air around the jet. . . The air would easily flow in from along the 'bumpy' outside of the nozzle and follow the jet away from the nozzle - with the SAME kind of turbulence we see with an ordinary jet out in the open with turbulence around the ever widening jet. . He is ABSOLUTELY INCORRECT at 1:46 when he says: "So, once again when we have a high velocity, we have a low pressure." <--WRONG!. . It takes all of these constraints {or boundary conditions} for this pressure reduction to happen. . Bernoulli happens going from the elevated pressure NSIDE any blower to the lower atmospheric pressure outside the blower that we see the combination of the speed increase along with the pressure decrease as we move ALONG the flow. . The pressure within the jet decreases TO atmospheric pressure NOT below it.!. . . If that nozzle had a knife edge opening such that the ID of the nozzle and hose were identical, this would NOT happen. . PLEASE REPLY if you follow this. I am 100.00% certain this is the true physics. . Regards.

@@ozkroca9003 P.S. I also reviewed his other videos and I see he has several others on Bernoulli and repeats common demos and associated misconceptions, so he does not understand the physics, sorry. It is so frustrating.

It's because of the internal energy of the gas which is used to break the van der Waals attraction and hence when it expands the gas molecules has lesser internal energy.... that's what cause the cooling sneek

There may be a loss of heat as they collide with each other and the walls of the cylinder but doesn't the cylinder also have its own heat that it can transfer to the gas molecules? Also your final analysis agrees with the purpose of the video to show how expansion cools gas

@@a-boardmanshawn7314 The heat transferred from the cylinder to the gas is negligible. To be honest, I'll have to watch the video again. It's been 2 months.