A customer is looking over our air-conditioning units when he stops and stares thoughtfully at one.

Customer: “I always wondered, where does the cold air from the AC come from?”

Me: “The unit takes heat out of the air that’s already inside the room. Refrigerant absorbs that heat, carries it through the system, and releases it outside. The cooler air is then circulated back into the room.”

Customer: “Okay, but where does the cold air come from?”

Me: “It doesn’t bring cold air in from somewhere else. It cools the air that’s already around you.”

Customer: “How?”

Me: “Think of it like a refrigerator. A refrigerator doesn’t have a supply of cold inside it. It moves heat from the inside of the fridge to the outside. An air conditioner does the same thing with a room.”

Customer: “Right, but where is it getting the cold air?”

Me: “It pulls in the warm air from your room, removes some of the heat, and blows that same air back out cooler.”

Customer: “So it makes cold air?”

Me: “Not exactly. Cold isn’t something being added. Heat is being removed.”

He looks increasingly frustrated.

Customer: “Look, I just want to know if it’s connected to a pipe with the cold air coming through or whatever.”

Me: “There isn’t a pipe supplying it with cold air.”

Customer: “If we’re importing cold air from Canada, then I’m not interested, but if it’s coming from the USA then that’s okay…”

I used to work at a tea and coffee shop where we brewed every drink fresh. A woman comes to the counter and orders an unsweetened green tea.

Me: “Certainly. It’ll take about five minutes because we brew it fresh.”

Customer: “That’s fine.”

I begin making her drink. As soon as she sees me heating water and measuring out the tea leaves, she starts looking visibly upset.

Customer: “Wait. What are you doing?”

Me: “Making your green tea.”

Customer: “You’re just using water and tea leaves?”

Me: “Yes, ma’am.”

Customer: “Then why would I pay four dollars for it? I could make that at home for a fraction of the price!”

Me: “We ensure that our water preserves the perfect ratio of two hydrogen atoms bonded with one oxygen atom, providing a consistently crisp water taste.”

She considers this for a moment.

Customer: “Oh. Okay, then. That’s fine.”

Related:
H2-Slow, Part 35
H2-Slow, Part 34
H2-Slow, Part 33
H2-Slow, Part 32
H2-Slow, Part 31

I used to work at a bowling center. A group of six got bent out of shape when a group couldn’t bowl a single game for $2.99.

Customer: “But your website says it’s $2.99 per game!”

Me: “It’s $2.99 per person, per game!”

Customer: “That’s misleading!”

Me: “You know what? You’re right! I can’t wait until later tonight when I go to buy one movie ticket and then bring five friends along for free so we can all enjoy the movie, right?”

Customer: *Glares.*

Me: “And oh, happy day! Now I can finally afford to take my family to Disneyland since I only have to pay for one ticket, and—”

Customer: “—Okay, okay! We get it! Shut up!” *Pays.*

Back in 2008, the Large Hadron Collider at CERN was turning on and showing up in the news. It was my mum’s first exposure to particle physics, and so, of course, she aligned herself with all the ‘end of the world’ misinformation that fed all the clickbait at the time.

Mum: “But they said it might make a black hole!”

Me: “Mum, do you know what a black hole is?”

Mum: “Well, no, but I can’t ever think of falling into any kind of hole as a good thing.”

I try my best as a layman to explain what the LHC actually does, and tell her what subatomic particles are for the first time in her life.

Mum: “But… but what happens if all the subatomic particles spill out and get everywhere?”

Me: “Mum, you’re gonna blow a gasket when you find out what you’re made of…”

I’m in the middle of a three-hour flight. A guy in front of me calls the flight attendant over.

Flight Attendant: “Yes, sir?”

Passenger: “Could you turn the noise down? It’s too loud.”

Flight Attendant: “Noise?”

Passenger: “Yes! That humming and vibrating. It’s very distracting.”

This passenger and I are in that group of rows next to the wing and engine.

Flight Attendant: “You mean the engine?”

Passenger: “Whatever it is that’s causing that noise!”

Flight Attendant: “Sir, allow me to politely explain how airplanes work…”

I tried not to laugh as this guy got a child’s explanation of aerodynamics. After the flight attendant leaves, I hear the passenger say to his partner sniffily:

Passenger: “We’re more than halfway there, I’m sure we could just glide the rest of the way…”