xkcd #3099: Neighbor-Source Heat Pump
Title text:
The installation of the pipes on the inside of the insulation can be challenging, especially when the neighbor could come home at any minute.
Transcript:
Transcript will show once it’s been added to explainxkcd.com
Source: https://xkcd.com/3099/
Title text:
Ultimately, history would imperfectly record the story of the Foal of Troy.
Transcript:
[A horse is facing Cueball and Ponytail, who are standing in front of an entrance below a tower.]
[In an inset panel, Cueball is talking to Megan and Hairy.]
Cueball: When the Greeks departed, they left behind a horse as a gift.[Hairbun is standing behind a horse, with Cueball standing in front.]
We took it as a gesture of peace, but it carried a secret payload.[A smaller horse is standing behind the horse from previous panel, which is looking behind at it.]
One night, from within the horse, another, smaller horse emerged![Close-up on Cueball.]
Cueball: Our guards have been unable to determine the inner horse's objective, but it has begun to show an interest in our oats.
Off-panel voice 1: An attack on Troy's food supply!
Off-panel voice 2: How dare they!?
Source: https://xkcd.com/3098/
Title text:
Pontoon bridges are just linear open-sided waterbeds.
Transcript:
Bridge Types
[A 4x4 matrix of 16 ways to cross the same rectangular hole in the ground]
Plank [shows a plank laid over the hole]
Rope [shows a rope bridge with rope guardrail]
Truss [shows a truss bridge with a triangular truss above the bridge deck]
Trestle [shows a trestle bridge]
Arch [shows stone arches supporting a straight deck]
Suspended Arch [shows a single arch, with the bridge deck suspended from it]
Draw [shows a truss bridge, with one half opened like an unrealistic draw bridge]
Suspension [shows the bridge deck suspended from a cable strung between two pillars and the shores]
Filler [shows the hole filled with dirt and stones]
Budget Overrun [shows a bridge deck suspended by cables from an artistically shaped pillar]
Jump [shows two ramps at the edges of the hole, and a skateboarder jumping across the hole]
Halfhearted [shows a ramp at each side of the hole that leads down to the bottom]
Waterbed [shows the hole filled with water, two fish and an octopus, a wobbly covering, and two stick figures crossing]
L'Engle [shows the hole warped such that the opposite shores meet]
Fun [shows a loop-de-loop rollercoaster bridging the hole, and a skateboarder using it to get across]
Repurposed Elevator [shows an elevator tower, rotated sideways as a whole, laid across the hole. 2 stick figures using the elevator are also rotated.]
Source: https://xkcd.com/3097/
Title text:
They say it's probably safe to keep orbiting for a while, but if it stays on or starts flashing we might have to call someone.
Transcript:
[A pattern in the form of a "check engine" light (as displayed on a car's instrument panel) is shown on the surface of the Sun, in the bottom right quarter. The pattern has a pictogram of a motor on the top and the text "Check Engine" below it, both in orange inside a black square, matching the orange color of the Sun.]
[Caption below the panel:]
This new sunspot cluster has raised concern among astronomers
Source: https://xkcd.com/3096/
Title text:
Under the two-domain system, anyone who punches you is technically an Archaean pathogen.
Transcript:
[Cueball, Megan, and White Hat are standing in a lab in front of a root-like phylogeny diagram, looking at it. Behind them is a desk with a microscope on it. There is a pile of items behind it and one item in front. From the plate on the microscope where the sample is, there is a star burst and a line going up to the text said by the sample.]
Cueball: It's weird how, despite being one of the main branches of the tree of life, no Archaea species are known to cause disease in humans.
Megan: Personally, I think it's because those gross methane breathers are too weird and incompetent to figure out how to hurt us even if they wanted to.
Archaea sample: Hey![Caption below the panel:]
Bad news: After overhearing a conversation in our lab, Archaea has finally started harming humans.
Source: https://xkcd.com/3095/
Title text:
Patients at least found it to be an improvement over Millikan's incredibly messy and unpleasant oil drop suspension procedure.
Transcript:
[Ponytail, wearing a lab coat, is giving a balloon to Cueball. Behind Cueball, there is a ramp on the ground, a magnet hanging from the ceiling, and a target on a poster on the wall.]
Ponytail: Rub this balloon against your head, then go jump past that magnet toward the target on the wall.[Caption below the panel:]
Before the bathroom scale was invented, the only way to weigh people was mass spectrometry.
Source: https://xkcd.com/3094/
Title text:
A 5% efficiency gain at the cost of a 99% efficiency loss
Transcript:
[A rocket with two boosters is launching going towards the top right corner. It has a two-stage core and two boosters, and they produce three flames from their exhaust and beneath these flames is a large exhaust plume fanning out behind the rocket most of the way towards the bottom of the panel. A smaller rocket is following the first rocket. It is very close to the first rocket, so most of the smaller rocket is inside the exhaust plume from the larger rocket. The smaller rocket does not have boosters, but still produces three smaller flames from its exhaust. Beneath these flames the smaller rocket also leaves a large but slimmer exhaust plume that exits the panel at the bottom left corner.]
[Caption below the panel:]
Aerospace tip: Although the technique reduces atmospheric drag for many types of vehicles, you should never try to improve rocket launch efficiency through drafting.
Source: https://xkcd.com/3093/
Title text:
169 is a baker's gross.
Transcript:
Transcript will show once it’s been added to explainxkcd.com
Source: https://xkcd.com/3092/
Title text:
Applying renormalization to bullies successfully transformed Pete & Pete's Endless Mike into Finite Mike.
Transcript:
Cueball poking an atom. Megan looks at it with a hand on her chin]
Cueball: Hey, electron!
Cueball: Stop hitting yourself!
Cueball: Stop hitting yourself!
Megan: ...Wait.[Caption below the panel:]
Renormalization actually started out as an effort to bully electrons.
Source: https://xkcd.com/3091/
Title text:
Turning in other directions can be accomplished by using a magnetized centerboard and ocean currents, since a current flowing through a magnetic field induces a Laplace force.
Transcript:
[Four panels show a schematic sail boat, seen from above, to indicate how it can sail into the wind. In the first panel the boat is heading straight up in the panel. The sail is fixed at the bow and describes a slight curve going to the right of the boat and then curving to the left, ending close to the stern. The rudder can be seen behind the boat. Five arrows, pointing towards 4:30 on a clock face, are drawn at the top left part of the boat, indicating the direction of the wind. There is a frame above the drawing of the boat with text. And then the arrows are labeled, and small lines going to the sail and the hull of the boat connects with two more labels:]
How sailboats use physics to sail upwind:
Wind
Boat
Sail[In the second panel the boat is drawn similar to panel 1, but the wind arrow have been changed to showing how the wind now blows past the sail on either side. This is done with two lines of three arrows that goes on either side of the sail, and the second and third arrow bends to follow the curve of the sail. Charged ions are shown across both sides of the sail with positive on the left side of the sail, (over the hull of the boat) and negative on the right side, over the sea to the right and behind the boat. The positive charges are small + signs in circles and the negative minus signs in circles. Above the drawing there is the following text:]
1. Wind passing over the sail strips away electrons via the triboelectric effect.[In the third panel the boat has turned towards right and has been moved closer to the bottom of the panel (this could be to acomodate more text above though). The entire hull is now covered in positive charges. A large broad dashed vector is shown going in the direction of the wind. The arrow is not over the boat but on either side of it, with the arrow head ending right of the stern of the boat. Two thin arrows are shown above the end of the force vector. A short solid arrow, that points along the same direction as the large arrow. And then a dashed arrow is drawn perpendicular to the first of these thin arrows (pointing along 1:30 on a clock face. Above the drawing there is the following text:]
2. The positively charged boat is blown downwind; its movement in Earth's magnetic field produces a Lorentz force.[In the fourth panel the boat has turned even more towards right and is back to the same height in the panel as the first two panels. The entire hull is still covered in positive charges. The broad dashed vector is still shown, but after starting in the wind direction it can be seen to turn slightly upwards before reaching the boat. And then when it comes out the other side of the boat it points in the direction of the bow of the boat, the arrow ending in front and a bit to the right of the boat. The two thin arrows from before are now shown to the left of the boat , with the short solid arrow pointing along the same direction as the start of the large arrow. And then a the dashed arrow drawn perpendicular to the first of these thin arrows pointing in the direction the boat is sailing. Above the drawing there is the following text:]
3. The Lorentz force acts perpendicular to the direction of motion, redirecting the boat upwind.
Source: https://xkcd.com/3090/
Title text:
P.S. If you have time travel, come to my birthday party Saturday!
Transcript:
[Cueball approaches Ponytail, chiselling a rock on a shoreline next to a river with shallow rolling hills in the background]
Cueball: What are you doing?
Ponytail: This river empties onto a passive continental margin.[Cueball and Ponytail stand talking, Ponytail holding several flat rocks, in an otherwise empty and frameless panel]
Ponytail: If I chisel notes onto these rocks and throw them into the sea, they might be incorporated into some shale cliff in the distant future.[Silhouetted scene of Ponytail as she throws multiple rocks off frame to the right, Cueball watching from behind her]
[From off-panel, sound effect of a rock hitting water:] PLOP[Two 'bug-eyed aliens', sitting in personal 'hover-saucers' look rightwards at an exposed rock-face. A pick and shovel are left stuck in the ground, and one of the 'saucers' sports a mechanical arm currently holding a loose fragment of rock]
[Panel label:] 100 million years later
[Text originating from the held rock fragment:] This bedrock inspected by No. 5
Source: https://xkcd.com/3088/
Title text:
Reductio ad absurdum fails when reality is absurd.
Transcript:
At the left, a teacher is holding a pointer, pointing at a picture on the screen.]
[The picture shows a hydraulic lift, with a small fluid vessel on the left connected to a tube at the bottom, which connects to a large vessel on the right. On top of the large vessel is a weight labeled 1000 and a Cueball. The fluid in the large vessel is labeled with an upward arrow. Megan's hand is over the small vessel, with a downward arrow indicating that she's pressing on it.]
[Cueball, Hairbun, and Blondie are sitting at school desks going right to left.]
Cueball: No, that can't be right.
Cueball: If hydrostatic pressure worked that way, then you could use it to make machines that exert near-infinite force.
Cueball: And ancient people could have demolished entire mountains just by drilling small tunnels and filling them with water.
[Caption below comic:]
When I first learned about Pascal's law, I tried to disprove it by showing that it would lead to absurd consequences, but it turns out hydraulic presses and ruina montium are both real things.
Source: https://xkcd.com/3087/
