Explaining the world one sketch at a time

Sketchplanations makes complex ideas simple with clear, insightful sketches. Explore topics from science, creativity, psychology, and beyond explained in pictures.

New sketches by email

Learn something new in a sketch each Sunday

Recent sketches

Earth is a big magnet.

Which is kind of amazing. The magnetic field is produced by some remarkable result of the convection of molten hot iron alloys in the core of the Earth. Kind of hard to really get your head round if you’re sitting calmly at your desk or walking on a nice stable surface. Periodically, the poles switch round it seems but at the moment the magnetic South pole is actually near the point we’d normally call the geographical North pole. They’re pretty close, but the geographic axis doesn’t exactly coincide along the geographic axis of rotation of Earth. And the lines of force go from magnetic North to magnetic South so your compass needle is actually pointing towards magnetic South. Remember iron filings and bar magnets from physics class?…Which is kind of amazing. The magnetic field is produced by some remarkable result of the convection of molten hot iron alloys in the core of the Earth. Kind of hard to really get your head round if you’re sitting calmly at your desk or walking on a nice stable surface. Periodically, the poles switch round it seems but at the moment the magnetic South pole is actually near the point we’d normally call the geographical North pole. They’re pretty close, but the geographic axis doesn’t exactly coincide along the geographic axis of rotation of Earth. And the lines of force go from magnetic North to magnetic South so your compass needle is actually pointing towards magnetic South. Remember iron filings and bar magnets from physics class?

29 Dec 2016

MOSCOW Prioritisation

A way of helping decide what to do next based on Must do, Should do, Could do and Would do. Strangely, so many of the things you’d really like to do when put in this organisation end up in the Would bucket.…

20 Dec 2016

The piston

The piston is an amazingly simple, ridiculously useful and successful mechanism that, together with a connecting rod and crankshaft, converts linear motion to rotational motion. This simple system is basically what allows us to take a force produced by, say, steam or an explosion and make a wheel turn. Stick a few of these together and time the rotation of each correctly, carefully controlling the explosions and the exhaust, and you have an internal combustion engine that powers and moves our cars. There are a lot of amazing things to me about it, but I am still impressed with how effectively it takes something moving back and forth and makes something spin around and vice versa.…The piston is an amazingly simple, ridiculously useful and successful mechanism that, together with a connecting rod and crankshaft, converts linear motion to rotational motion. This simple system is basically what allows us to take a force produced by, say, steam or an explosion and make a wheel turn. Stick a few of these together and time the rotation of each correctly, carefully controlling the explosions and the exhaust, and you have an internal combustion engine that powers and moves our cars. There are a lot of amazing things to me about it, but I am still impressed with how effectively it takes something moving back and forth and makes something spin around and vice versa.

9 Dec 2016

Typical gastropod anatomy

For a closer look next time you’re at the beach. Pay close attention to whether you find one with a dextral or sinistral aperture. Gastropods are the largest class of molluscs which includes limpets, snails and sea slugs. For those who weren’t sure. Info from the 1971 book, Discovering Sea Shells by Barry Charles…

29 Nov 2016

The half-life of caffeine

The half-life of caffeine is about 4 hours. The data vary, but for a medium-sized adult, you can probably expect half of the caffeine from that 3 pm cup of coffee to still be doing half of its thing about 7 pm, 4 hours later. Apparently, smokers deal with caffeine quicker, and caffeine sticks around in children much longer. You can expect about 10 minutes before it first kicks in, which, I suppose, is why if you’re feeling tired while driving, it’s a decent plan to take a break and drink a coffee, then have a 15-minute nap. Once it starts to kick in, you might hit peak caffeine any time from 45 minutes to 2 hours later. Caveat: The chart visualisation is extrapolated from reported data, so the shape is only approximate. Some references say longer, and some say from 3-9 hours or so. My source, which seemed pretty comprehensive, was: Bertil B. Fredholm, Karl Bättig, Janet Holmén, Astrid Nehlig and Edwin E. Zvartau, Actions of Caffeine in the Brain with Special Reference to Factors That Contribute to Its Widespread Use, Pharmacological Reviews March 1999, 51 (1) 83-133; Also see: tiredness can kill, take a break.…The half-life of caffeine is about 4 hours. The data vary, but for a medium-sized adult, you can probably expect half of the caffeine from that 3 pm cup of coffee to still be doing half of its thing about 7 pm, 4 hours later. Apparently, smokers deal with caffeine quicker, and caffeine sticks around in children much longer. You can expect about 10 minutes before it first kicks in, which, I suppose, is why if you’re feeling tired while driving, it’s a decent plan to take a break and drink a coffee, then have a 15-minute nap. Once it starts to kick in, you might hit peak caffeine any time from 45 minutes to 2 hours later. Caveat: The chart visualisation is extrapolated from reported data, so the shape is only approximate. Some references say longer, and some say from 3-9 hours or so. My source, which seemed pretty comprehensive, was: Bertil B. Fredholm, Karl Bättig, Janet Holmén, Astrid Nehlig and Edwin E. Zvartau, Actions of Caffeine in the Brain with Special Reference to Factors That Contribute to Its Widespread Use, Pharmacological Reviews March 1999, 51 (1) 83-133; Also see: tiredness can kill, take a break.

22 Nov 2016

Plutchik's Wheel of Emotions: a colourful wheel showing how emotions mix

Mapping emotions

This is Robert Plutchik’s wheel of emotions. I like it because it tries to make sense out of the range of emotions we have by relating his 8 primary emotions to related ones where two primary emotions meet. For example, remorse is like feeling both disgust and sadness; awe is surprise and fear. On opposite sides of the wheel are opposite emotions eg, Joy >< Sadness Other versions of his framework go 3D and map the intensity of emotions as well, for example, rage > anger > annoyance, or ecstasy > joy > serenity. Neat.…This is Robert Plutchik’s wheel of emotions. I like it because it tries to make sense out of the range of emotions we have by relating his 8 primary emotions to related ones where two primary emotions meet. For example, remorse is like feeling both disgust and sadness; awe is surprise and fear. On opposite sides of the wheel are opposite emotions eg, Joy >< Sadness Other versions of his framework go 3D and map the intensity of emotions as well, for example, rage > anger > annoyance, or ecstasy > joy > serenity. Neat.

16 Nov 2016

Search·Categories·Archive·List