Sketchplanations - A weekly explanation in a sketch

Sketchplanations in a book! I think you'll love Big Ideas Little Pictures

Sketchplanations podcast photo of Rob Bell, Tom Pellereau and Jono Hey

Prefer to listen?
Try the podcast

Like Sketchplanations?
Support me on Patreon

Explaining the world one sketch at a time

What is a blue moon?

What is a blue moon? A blue moon is a full moon that hits twice in a calendar month. Given the cycle from full moon to full moon is about 29.5 days and months are generally 30 or 31 days a full moon appearing twice in a month doesn’t happen very often. And February never has a blue moon. I like this definition, but it is apparently a modification of the original definition which is a little more complicated. The original blue moon definition is explained like this. Given the 29.5 day cycle, most seasons of 3 months have 3 full moons. But every now and then, a season would come by, like Sep, Oct, Nov in the sketch, where there would be 4 full moons. The 3rd of these was known as a blue moon, or a seasonal blue moon. See why I like the modern definition? Here’s a good article that explains the subtleties and history of blue moons. Check out more moon or astronomy explanations…What is a blue moon? A blue moon is a full moon that hits twice in a calendar month. Given the cycle from full moon to full moon is about 29.5 days and months are generally 30 or 31 days a full moon appearing twice in a month doesn’t happen very often. And February never has a blue moon. I like this definition, but it is apparently a modification of the original definition which is a little more complicated. The original blue moon definition is explained like this. Given the 29.5 day cycle, most seasons of 3 months have 3 full moons. But every now and then, a season would come by, like Sep, Oct, Nov in the sketch, where there would be 4 full moons. The 3rd of these was known as a blue moon, or a seasonal blue moon. See why I like the modern definition? Here’s a good article that explains the subtleties and history of blue moons. Check out more moon or astronomy explanations

7 Apr 2018

Rival and non-rival goods

This is surely at least part of the reason that “software is eating the world.” But I’m sure coffee will stick around for a bit too.…

31 Mar 2018

Crossmodal perception

Crossmodal perception is when senses interact in sometimes surprising ways. Some fun examples: Coffee tastes better when you don’t have a loud coffee machine near you, and it also tastes more intense and less sweet if the mug is white. In the atmosphere of a pressurised cabin when flying, with decreased humidity and air pressure and significant background noise, things taste less sweet or salty. If you can’t hear the crunch of, say, a Pringles potato chip, then it tastes less fresh. You might enjoy Nicola Twilley’s super New Yorker article, The Illusion of Taste, which has more of the science and plenty more examples.…Crossmodal perception is when senses interact in sometimes surprising ways. Some fun examples: Coffee tastes better when you don’t have a loud coffee machine near you, and it also tastes more intense and less sweet if the mug is white. In the atmosphere of a pressurised cabin when flying, with decreased humidity and air pressure and significant background noise, things taste less sweet or salty. If you can’t hear the crunch of, say, a Pringles potato chip, then it tastes less fresh. You might enjoy Nicola Twilley’s super New Yorker article, The Illusion of Taste, which has more of the science and plenty more examples.

24 Mar 2018

The Lucretius problem

The Lucretius problem is our tendency to believe that the worst possible thing that can happen is the worst possible thing we know has happened. The name was given by Nicolas Taleb in his book Antifragile. So, should we plan to stress test an investment portfolio, for example, we might test it against how it fared in the worst market crash. Or stress test a building for the biggest known earthquake or a nuclear reactor for the biggest known tsunami. And yet, when each of these events happened, they were bigger than what had come before, and the same could happen again. Lucretius was a Roman philosopher who wrote that: "The fool believes that the tallest mountain in the world will be equal to the tallest one he has observed." Also known as The Lucretius underestimation. See other sketchplanations on cognitive biases.…The Lucretius problem is our tendency to believe that the worst possible thing that can happen is the worst possible thing we know has happened. The name was given by Nicolas Taleb in his book Antifragile. So, should we plan to stress test an investment portfolio, for example, we might test it against how it fared in the worst market crash. Or stress test a building for the biggest known earthquake or a nuclear reactor for the biggest known tsunami. And yet, when each of these events happened, they were bigger than what had come before, and the same could happen again. Lucretius was a Roman philosopher who wrote that: "The fool believes that the tallest mountain in the world will be equal to the tallest one he has observed." Also known as The Lucretius underestimation. See other sketchplanations on cognitive biases.

17 Mar 2018

Seasons

The Earth’s tilt causes the changing seasons. As the Earth revolves around the sun, the tilt of its axis—23.5 degrees—causes the two hemispheres, North and South, to be either tilted towards the sun or away from it at different times of the year. In Winter, because light from the sun hits at a greater angle and closer to the poles, the solar energy gets spread over a larger area. This makes it weaker and cooler and gives rise to colder weather (aka winter). In summer, the sun's light hits more directly and is closer to the equator, so it’s concentrated on a smaller area, leading to hotter days. Because of the tile of the earth, seasons are reversed in the two hemispheres, so if it’s winter in the Northern Hemisphere, it’s summer in the Southern and vice-versa. The further from the equator you go, the bigger the effect of the seasons. As an example, temperatures in Ecuador stay relatively constant throughout the year, while the poles experience extremes of 24-hour daylight or 24-hour night and great freezes and thaws. A version of this sketch, along with a number of other planetary and seasonal ideas, features in my book Big Ideas Little Pictures Also see: Autumn leaves Equinox Solstice…The Earth’s tilt causes the changing seasons. As the Earth revolves around the sun, the tilt of its axis—23.5 degrees—causes the two hemispheres, North and South, to be either tilted towards the sun or away from it at different times of the year. In Winter, because light from the sun hits at a greater angle and closer to the poles, the solar energy gets spread over a larger area. This makes it weaker and cooler and gives rise to colder weather (aka winter). In summer, the sun's light hits more directly and is closer to the equator, so it’s concentrated on a smaller area, leading to hotter days. Because of the tile of the earth, seasons are reversed in the two hemispheres, so if it’s winter in the Northern Hemisphere, it’s summer in the Southern and vice-versa. The further from the equator you go, the bigger the effect of the seasons. As an example, temperatures in Ecuador stay relatively constant throughout the year, while the poles experience extremes of 24-hour daylight or 24-hour night and great freezes and thaws. A version of this sketch, along with a number of other planetary and seasonal ideas, features in my book Big Ideas Little Pictures Also see: Autumn leaves Equinox Solstice

10 Mar 2018

Lake-effect snow

Lake Effect Snow is a phenomenon where crazy amounts of snow can fall in massive storms on a lake’s downwind—leeward—side. Where the effect is pronounced, to the east of some of the Great Lakes in the U.S. (think Buffalo), it’s responsible for the regions known as the snow belt. It works like this: Cold air blows over a lake. As the cold air passes over the warmer lake, it picks up water vapor from the water, which warms the air. This causes the air to rise and, in turn, cool, such that when it reaches the downwind side of the lake, it has become cold and moist. This simple change can lead to some incredible snowstorms dumping 2 to 3 inches of snow per hour. Satellite pictures show it in action pretty clearly. If there is a rise in land elevation along the path of the cold air, the air can cool faster and increase the effect — and also cause a rain shadow. And if there’s a lot of convection and the air rises quickly, you can even get what’s called thundersnow—a thunderstorm in a snowstorm. Stay warm out there. More Weather Sketches Find the weather interesting? Me too. Also see: Dirty thunderstorms Thunderclouds Yesterday’s weather (applying weather forecasting to productivity forecasting) Rain shadow Lenticular clouds Know your cirrostratus from your altocumulus British weather Banner clouds For everyday weather-related phenomena explained, see Dennis Mersereau’s The Skies Above: Storm Clouds, Blood Moons, and Other Everyday Phenomena, Mountaineers Books (2022). Dennis is also the source of the lovely phrase Nature’s greatest snow machine.…Lake Effect Snow is a phenomenon where crazy amounts of snow can fall in massive storms on a lake’s downwind—leeward—side. Where the effect is pronounced, to the east of some of the Great Lakes in the U.S. (think Buffalo), it’s responsible for the regions known as the snow belt. It works like this: Cold air blows over a lake. As the cold air passes over the warmer lake, it picks up water vapor from the water, which warms the air. This causes the air to rise and, in turn, cool, such that when it reaches the downwind side of the lake, it has become cold and moist. This simple change can lead to some incredible snowstorms dumping 2 to 3 inches of snow per hour. Satellite pictures show it in action pretty clearly. If there is a rise in land elevation along the path of the cold air, the air can cool faster and increase the effect — and also cause a rain shadow. And if there’s a lot of convection and the air rises quickly, you can even get what’s called thundersnow—a thunderstorm in a snowstorm. Stay warm out there. More Weather Sketches Find the weather interesting? Me too. Also see: Dirty thunderstorms Thunderclouds Yesterday’s weather (applying weather forecasting to productivity forecasting) Rain shadow Lenticular clouds Know your cirrostratus from your altocumulus British weather Banner clouds For everyday weather-related phenomena explained, see Dennis Mersereau’s The Skies Above: Storm Clouds, Blood Moons, and Other Everyday Phenomena, Mountaineers Books (2022). Dennis is also the source of the lovely phrase Nature’s greatest snow machine.

3 Mar 2018

Search·Categories·Archive