explain xkcd - User contributions [en]

3171: Geologic Core Sample

2025-11-22T00:30:17Z

ChaoticVermillion:

{{comic
| number = 3171
| date = November 21, 2025
| title = Geologic Core Sample
| image = geologic_core_sample_2x.png
| imagesize = 493x789px
| noexpand = true
| titletext = If you drill at the right angle and time things perfectly, your core sample can include a section of a rival team's coring equipment.
}}

==Explanation==
{{incomplete|This page was created BY A RIVAL GEOLOGY TEAM. Don't remove this notice too soon.}}

This image presents a core sample taken by a slightly chaotic team of geologists. Contained within it are fairly normal ground matter such as "topsoil" and "granite" but also such things as "bottomsoil", which has no IRL parallel, parts of subway cars, arms of a spelunker most likely amputated by the sample, netherrack (a stone appearing in the Nether in Minecraft), a "balrog" wing (referencing a fictional animal from Lord of the Rings which first made an appearance in xkcd in [https://www.explainxkcd.com/wiki/index.php/730:_Circuit_Diagram]) and after diving through the core of the earth, the home of someone else. It first starts with cement, the foundation, floorboards and carpet (either a carpeted floor or a decorated floor), and then the posessions

The title text humorously refers to a "rival team" and their coring equipment - implying that with the correct angle you can muddle with their own coring experiment, which, outside of cold war-type pettiness, is not considered a constructive approach to science.

==Transcript==
{{incomplete transcript|Don't remove this notice too soon.}}
[This shows a drill sample with various labels]

Topsoil

Till

Granite Bedrock

Bottomsoil

Roof of Subway Car

Floor of Subway Car

More Granite

Municipal water main

Slightly different granite

Piece of screaming spelunker's arm

Cool Crystals with no resale value

Mangled Fragments of drillbit from previous attempt

Some boring intrusive rock that's basically granite but has a name like "diorite" or "andalite" that you always have to look up

Netherrack

Balrog wig

Granite

Topsoil

Cement

Floorboards

Carpet

Possesions of a confused and angry homeowner in the other hemisphere

{{comic discussion}}<noinclude>
[[Category:Geology]]
[[Category:Charts]]
[[Category:LOTR]]

3158: Shielding Chart

2025-10-23T10:50:23Z

ChaoticVermillion: some sharks

{{comic
| number = 3158
| date = October 22, 2025
| title = Shielding Chart
| image = shielding_chart_2x.png
| imagesize = 740x720px
| noexpand = true
| titletext = Sharks can occasionally travel short distances through air when pursuing prey, but their attenuation coefficient is pretty high.
}}

==Explanation==
{{incomplete|This page was created by a SPACE-BASED SHARK DEFENSE BOT. Don't remove this notice too soon.}}

This comic is part of a series on [[:Category:Confusion matrices|confusion matrices]].

Various hazardous (or merely obnoxious) materials, objects, and effects can have their danger reduced with specialized protective equipment. The yellow squares are where the shield fails to protect against the object. The grey-yellow squares are where the shield is partially successful, but still presents some risk. The grey squares are where the shield succeeds.

Some hazards, such as {{w|alpha particles}}, a form of radiation with particularly low penetrative power, can be easily deterred by common things; even a relatively short distance through air is enough to minimize their impact. Comparatively, more dangerous hazards, such as the far more penetrative {{w|gamma rays}}, are unaffected by all but the shielding methods actually intended for them.

The title text notes that, while the shark hazard is shown on the chart to be entirely nullified by a sufficient air barrier, in reality sharks are capable of attacking prey even if it is a short distance out of the water.

===Shielding Chart===
{| class="wikitable" | style="background:#E6C3C3;"
! Shielding Chart
! scope="col"| {{w|Air}}
! scope="col"| {{w|Lead}}
! scope="col"| {{w|Water}}
! scope="col"| {{w|Glass}}
! scope="col"| {{w|Vacuum}}
! scope="col"| {{w|Oven mitts}}
! scope="col"| {{w|Armor}}
! scope="col"| {{w|Hazmat suit|Bio-hazard suit}}
! scope="col"| {{w|Faraday cage}}
! scope="col"| {{w|Shark cage}}
|-
! scope="row"| {{w|Gamma rays}}
| style="background:#FBF8CE;"|Gamma rays are not shielded by air.
| style="background:#808080;"|Lead is commonly used as {{w|Lead shielding|shielding}} against gamma rays. Lead work because of its density and high atomic number, scattering gamma rays.
| style="background:#D5C58A;"|Water can be used to shield against gamma rays, but you need at least 10 feet of water between you and the gamma rays for it to work.
|colspan=7; style="background:#FBF8CE;"|Gamma rays have the highest energy of any type of light, and has no mass and no charge, making them pass through most materials easily.

|-
! scope="row"| {{w|Neutrons}}
| style="background:#FBF8CE;"|
| style="background:#D5C58A;"|
| style="background:#808080;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|

|-
! scope="row"| {{w|Alpha particles}}
| style="background:#808080;"|
| style="background:#808080;"|
| style="background:#808080;"|
| style="background:#808080;"|
| style="background:#FBF8CE;"|
| style="background:#808080;"|
| style="background:#808080;"|
| style="background:#808080;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|

|-
! scope="row"| {{w|Light}}
| style="background:#FBF8CE;"|
| style="background:#808080;"|
| style="background:#D5C58A;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|
| style="background:#808080;"|
| style="background:#808080;"|
| style="background:#808080;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|

|-
! scope="row"| {{w|Sound}}
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|
| style="background:#808080;"|
| style="background:#D5C58A;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|

|-
! scope="row"| {{w|Heat}}
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|
| style="background:#D5C58A;"|
| style="background:#808080;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|

|-
! scope="row"| {{w|Swords}}
| style="background:#FBF8CE;"|
| style="background:#808080;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|
| style="background:#808080;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|

|-
! scope="row"| {{w|Particulate matter#Health problems|Toxic dust}}
| style="background:#FBF8CE;"|
| style="background:#D5C58A;"|
| style="background:#FBF8CE;"|
| style="background:#808080;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|
| style="background:#808080;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|

|-
! scope="row"| {{w|Radio}}
| style="background:#FBF8CE;"|
| style="background:#808080;"|
| style="background:#808080;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|
| style="background:#808080;"|
| style="background:#FBF8CE;"|
| style="background:#808080;"|
| style="background:#FBF8CE;"|

|-
! scope="row"| {{w|Sharks}}
| style="background:#808080;"|Sharks cannot travel very far on land or in the air.
| style="background:#808080;"|
| style="background:#FBF8CE;"|Sharks live underwater, so water is not an effective shield against sharks. {{Citation needed}}
| style="background:#808080;"|
| style="background:#808080;"|
| style="background:#FBF8CE;"|Oven mitts are not very effective at stopping sharks.
| style="background:#D5C58A;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|A faraday cage is weak enough that a shark can rip through the cage, failing to protect the human inside.
| style="background:#808080;"|
|}

==Transcript==
{{incomplete transcript|Don't remove this notice too soon.}}
The whole comic is in one panel
A confusion matrix sits in the middle

Air:
*Gamma rays - Yellow
*Neutrons - Yellow
*Alpha particles - Gray
*Light - yellow
*Sound - yellow
*Heat - yellow
*Swords - yellow
*Toxic dust - yellow
*Radio - yellow
*Sharks - gray

Lead:
*Gamma rays - Gray
*Neutrons - Yellowish-grey
*Alpha particles -
*Light
*Sound
*Heat
*Swords
*Toxic dust
*Radio
*Sharks

Water:
*Gamma rays
*Neutrons
*Alpha particles
*Light
*Sound
*Heat
*Swords
*Toxic dust
*Radio
*Sharks

*Glass:
*Gamma rays
*Neutrons
*Alpha particles
*Light
*Sound
*Heat
*Swords
*Toxic dust
*Radio
*Sharks

Vacuum:
*Gamma rays
*Neutrons
*Alpha particles
*Light
*Sound
*Heat
*Swords
*Toxic dust
*Radio
*Sharks

Oven mitts:
*Gamma rays
*Neutrons
*Alpha particles
*Light
*Sound
*Heat
*Swords
*Toxic dust
*Radio
*Sharks

Armor:
*Gamma rays
*Neutrons
*Alpha particles
*Light
*Sound
*Heat
*Swords
*Toxic dust
*Radio
*Sharks

Biohazard suit:
*Gamma rays
*Neutrons
*Alpha particles
*Light
*Sound
*Heat
*Swords
*Toxic dust
*Radio
*Sharks

Faraday cage:
*Gamma rays
*Neutrons
*Alpha particles
*Light
*Sound
*Heat
*Swords
*Toxic dust
*Radio
*Sharks

Shark cage:
*Gamma rays
*Neutrons
*Alpha particles
*Light
*Sound
*Heat
*Swords
*Toxic dust
*Radio
*Sharks

{{comic discussion}}<noinclude>
[[Category:Confusion matrices]]
[[Category:Sharks]]
[[Category:Multiple Cueballs]]

3158: Shielding Chart

2025-10-23T09:54:53Z

ChaoticVermillion: Gamma ray explanations

{{comic
| number = 3158
| date = October 22, 2025
| title = Shielding Chart
| image = shielding_chart_2x.png
| imagesize = 740x720px
| noexpand = true
| titletext = Sharks can occasionally travel short distances through air when pursuing prey, but their attenuation coefficient is pretty high.
}}

==Explanation==
{{incomplete|This page was created by a SPACE-BASED SHARK DEFENSE BOT. Don't remove this notice too soon.}}

This comic is part of a series on [[:Category:Confusion matrices|confusion matrices]].

Various hazardous (or merely obnoxious) materials, objects, and effects can have their danger reduced with specialized protective equipment. The yellow squares are where the shield fails to protect against the object. The grey-yellow squares are where the shield is partially successful, but still presents some risk. The grey squares are where the shield succeeds.

Some hazards, such as {{w|alpha particles}}, a form of radiation with particularly low penetrative power, can be easily deterred by common things; even a relatively short distance through air is enough to minimize their impact. Comparatively, more dangerous hazards, such as the far more penetrative {{w|gamma rays}}, are unaffected by all but the shielding methods actually intended for them.

The title text notes that, while the shark hazard is shown on the chart to be entirely nullified by a sufficient air barrier, in reality sharks are capable of attacking prey even if it is a short distance out of the water.

===Shielding Chart===
{| class="wikitable" | style="background:#E6C3C3;"
! Shielding Chart
! scope="col"| {{w|Air}}
! scope="col"| {{w|Lead}}
! scope="col"| {{w|Water}}
! scope="col"| {{w|Glass}}
! scope="col"| {{w|Vacuum}}
! scope="col"| {{w|Oven mitts}}
! scope="col"| {{w|Armor}}
! scope="col"| {{w|Hazmat suit|Bio-hazard suit}}
! scope="col"| {{w|Faraday cage}}
! scope="col"| {{w|Shark cage}}
|-
! scope="row"| {{w|Gamma rays}}
| style="background:#FBF8CE;"|Gamma rays are not shielded by air
| style="background:#808080;"|Lead is commonly used as {{w|Lead shielding|shielding}} against gamma rays. Lead work because of its density and high atomic number, scattering gamma rays.
| style="background:#D5C58A;"|Water can be used to shield against gamma rays, but you need at least 10 feet of water between you and the gamma rays for it to work.
|colspan=7; style="background:#FBF8CE;"|Gamma rays have the highest energy of any type of light, and has no mass and no charge, making them pass through most materials easily.

|-
! scope="row"| {{w|Neutrons}}
| style="background:#FBF8CE;"|
| style="background:#D5C58A;"|
| style="background:#808080;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|

|-
! scope="row"| {{w|Alpha particles}}
| style="background:#808080;"|
| style="background:#808080;"|
| style="background:#808080;"|
| style="background:#808080;"|
| style="background:#FBF8CE;"|
| style="background:#808080;"|
| style="background:#808080;"|
| style="background:#808080;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|

|-
! scope="row"| {{w|Light}}
| style="background:#FBF8CE;"|
| style="background:#808080;"|
| style="background:#D5C58A;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|
| style="background:#808080;"|
| style="background:#808080;"|
| style="background:#808080;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|

|-
! scope="row"| {{w|Sound}}
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|
| style="background:#808080;"|
| style="background:#D5C58A;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|

|-
! scope="row"| {{w|Heat}}
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|
| style="background:#D5C58A;"|
| style="background:#808080;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|

|-
! scope="row"| {{w|Swords}}
| style="background:#FBF8CE;"|
| style="background:#808080;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|
| style="background:#808080;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|

|-
! scope="row"| {{w|Particulate matter#Health problems|Toxic dust}}
| style="background:#FBF8CE;"|
| style="background:#D5C58A;"|
| style="background:#FBF8CE;"|
| style="background:#808080;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|
| style="background:#808080;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|

|-
! scope="row"| {{w|Radio}}
| style="background:#FBF8CE;"|
| style="background:#808080;"|
| style="background:#808080;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|
| style="background:#808080;"|
| style="background:#FBF8CE;"|
| style="background:#808080;"|
| style="background:#FBF8CE;"|

|-
! scope="row"| {{w|Sharks}}
| style="background:#808080;"|
| style="background:#808080;"|
| style="background:#FBF8CE;"|
| style="background:#808080;"|
| style="background:#808080;"|
| style="background:#FBF8CE;"|
| style="background:#D5C58A;"|
| style="background:#FBF8CE;"|
| style="background:#FBF8CE;"|
| style="background:#808080;"|
|}

==Transcript==
{{incomplete transcript|Don't remove this notice too soon.}}
The whole comic is in one panel
A confusion matrix sits in the middle

Air:
*Gamma rays - Yellow
*Neutrons - Yellow
*Alpha particles - Gray
*Light - yellow
*Sound - yellow
*Heat - yellow
*Swords - yellow
*Toxic dust - yellow
*Radio - yellow
*Sharks - gray

Lead:
*Gamma rays - Gray
*Neutrons - Yellowish-grey
*Alpha particles -
*Light
*Sound
*Heat
*Swords
*Toxic dust
*Radio
*Sharks

Water:
*Gamma rays
*Neutrons
*Alpha particles
*Light
*Sound
*Heat
*Swords
*Toxic dust
*Radio
*Sharks

*Glass:
*Gamma rays
*Neutrons
*Alpha particles
*Light
*Sound
*Heat
*Swords
*Toxic dust
*Radio
*Sharks

Vacuum:
*Gamma rays
*Neutrons
*Alpha particles
*Light
*Sound
*Heat
*Swords
*Toxic dust
*Radio
*Sharks

Oven mitts:
*Gamma rays
*Neutrons
*Alpha particles
*Light
*Sound
*Heat
*Swords
*Toxic dust
*Radio
*Sharks

Armor:
*Gamma rays
*Neutrons
*Alpha particles
*Light
*Sound
*Heat
*Swords
*Toxic dust
*Radio
*Sharks

Biohazard suit:
*Gamma rays
*Neutrons
*Alpha particles
*Light
*Sound
*Heat
*Swords
*Toxic dust
*Radio
*Sharks

Faraday cage:
*Gamma rays
*Neutrons
*Alpha particles
*Light
*Sound
*Heat
*Swords
*Toxic dust
*Radio
*Sharks

Shark cage:
*Gamma rays
*Neutrons
*Alpha particles
*Light
*Sound
*Heat
*Swords
*Toxic dust
*Radio
*Sharks

{{comic discussion}}<noinclude>
[[Category:Confusion matrices]]
[[Category:Sharks]]
[[Category:Multiple Cueballs]]