Tom Elwood -best of the internet.

Monday, January 22, 2024

Replacing an airplane wheel assembly

https://youtu.be/QQWrL9aRfLM?si=GN8ln60mdQ-Rlt9M

I found this interesting. He explains a little about how the brakes work, how the wheel is held together, what can fail, how the brakes are cooled, built-in redundancy, and how is tested before being returned to service.

Sunday, January 21, 2024

Veritasium on luck and survivor bias

This is the video, well worth watching, where he candidly explains the story of how he wanted to become a filmmaker, then an engineer, then a tutor. At 7:45 the heartwarming story of meeting his wife, and at 9:14 a very insightful look at the survivor bias. https://youtu.be/S1tFT4smd6E?si=JzTsii5vJaaALri2

And this video looks at inequality in the world and how we should and shouldn't view our success. At 5:00 he starts to get very philosophical about his own success and how he met his wife by chance. And at 9:34 he talks about how luck figured into his own success.

https://youtu.be/3LopI4YeC4I?si=SM5VGMLCvVhNMNPB

Saturday, January 20, 2024

Deep dive - how Pop-up tents work

https://youtu.be/-HDSPCMZNws?si=xIw96_J04PSjohrk

Steve Mould takes a deep dive into how a pop-up tent folds. I love his videos because he really goes into depth and gives visual examples that are remarkable clear.

Lava flows

https://youtu.be/QjHpxzzNSEg?si=AGapCOp31g64Ipe7

Lava flows vary widely in viscosity depending on silica content.

2:16 but the least viscous lava is still 10 times more viscous than honey.

Here's a lab that melts rocks and studies how lava flows. https://www.sciencefriday.com/articles/the-geologists-who-control-lava/

Friday, January 19, 2024

Why so cold?

https://www.forbes.com/sites/startswithabang/2019/01/30/this-is-why-global-warming-is-responsible-for-freezing-temperatures-across-the-usa/amp/

Unstable polar temperature fronts are the explanation for our unusually cold temperatures recently.

Wednesday, January 17, 2024

What Heart Rate Variability Means on Your Fitness Tracker HRV

https://www.realsimple.com/health/preventative-health/heart-health/what-is-heart-rate-variability

"normal HRV for people in their teens and 20s averages between 55 and 105 milliseconds, but most folks aged 60 years and up have lower heart rate variability, averaging between 25 to 45 milliseconds."

"Your HRV may increase when you start managing stress and improving your food choices, getting regular exercise, staying hydrated, drinking less alcohol, and sleeping for a solid seven to nine hours each night."

Denver airport

https://youtu.be/fO-qr4G6E1o?si=uyPRqzov2SXh5Pu1

Some pretty impressive facts about Denver airport.

1:29 6th busiest airport in the world, by seats flown per day, 0:22 edging towards 100 million passengers per year.

0:39 450 flights a day to 175 destinations

3:01 40,000 employees

3:42 largest airport in US at 53 mi²

Saturday, January 13, 2024

Python trading bot

https://youtu.be/WcfKaZL4vpA?si=8RaoXCT11A8Fi0y0

Discusses in detail how the bot works to search for engulfing candle trading pattern and executes trades automatically.

Here he experiments with a VWAP Bollinger band algorithm.

https://youtu.be/RbQaARxEW9o?si=UeyNiyCkmhuAI-k_

How many ancient trees am I burning per mile in my car?

https://youtu.be/SD9yVca6hHI?si=9eCr8CSKkjGwo_n_

7 tips for making the PERFECT pancakes!

Here's the sales pitch for a new, fluffier flour made from popcorn.

https://youtu.be/xminCJAmqxY?si=CqUp72V9_WRhqVbK

Here are some tips for making perfect pancakes with this unusual flour.

GIMME 15% OFF

Friday, January 12, 2024

Where Do Feelings Come From? | Hidden Brain

The brain is constantly predicting. Predicting is metabolically more efficient than reacting.

The brain's job is coordinating and regulating the functions of the body in the most energy-efficient way. It's running a budget.

33:29 "The most effective way to run a system is to predict the state of the system and correct when necessary. It's not to wait and react to things. Reaction is more expensive metabolically than prediction - and [hence] a major selection pressure on a species, but also on an individual. An individual's ability, for example, to remain healthy and to be able to reproduce pass its genes onto the next generation is metabolic fitness, metabolic efficiency... In psychology, we don't experience every hug we give every, every emotion we experience, every thought we have, every insult we bear. We don't experience these things in metabolic terms, we experience them in psychological terms. But there's always a metabolic cost because there's always electrical and chemical signaling going on underneath the hood. And it turns out that the metabolic cost of signaling is a major, major concern that any organism system has to deal with.

45:45 "Your brain is running a budget for your body. It's not budgeting money, it's budgeting glucose and salt and oxygen... Depression is like a bankrupt body budget. It's basically your brain is attempting to reduce its costs, and in doing this, it will create fatigue, which will lead you to move less [, yielding] a reduction in cost. The brain is like trapped in its predictions. It's not going to update, it's not going to learn from prediction error because learning is metabolically expensive. So even if there are pleasant things in the world that could lead you to experience pleasure, you won't pay attention to them and you won't learn about them...because it's just too expensive. So basically, the brain is trapped in these predictions that will lead to more unpleasant or continuing unpleasant mood. So when you feel stressed, it's because your brain has predicted that a big metabolic outlay is going to be necessary in the next moment.

Depression is because your brain has predicted that a big emotional outlay is being predicted, and it's avoiding that energy.

https://hiddenbrain.org/podcast/where-do-feelings-come-from/

transcript at https://app.podscribe.ai/episode/94541962

This is similar to research on the visual cortex, where the brain is constantly predicting what it's "about to see," rather than what it has seen. A simple MRI experiment demonstrated the brain predicts an expected movement of dots from a previously-established sequence. https://neurosciencenews.com/vision-event-experience-6797/

Likewise, a flash-card experiment concluded "visual representations are skewed toward future states" https://elifesciences.org/articles/78904

In a review, the author points out that "what we expect to hear or see interferes with, and even supersedes, what we actually hear and see." https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6400266/