4 ms·

When I was a kid we had an above ground pool that was about 3 feet/~1 m deep. One day in the shed I found a 6 foot/2m length of hose that looked to be about the

When I was a kid we had an above ground pool that was about 3 feet/~1 m deep. One day in the shed I found a 6 foot/2m length of hose that looked to be about the same diameter as the tube on the my little snorkel. Ah ha! I can attach this to my snorkel, tie the other end to a pool float and breath under water like a diver! My idea did not work out as planned. At the surface I was able to breath through the hose but once I tried to "dive" down I found that drawing a breath was difficult. At the full depth I could not draw a breath. I told my father later on (who was an engineer) and he explained the physics of water pressure.

robocat 5y ago
That was dangerous due to the risk of hypercapnia: "increased CO2 levels could lead to unconsciousness which, if happening while in the water, can result in drowning.". Note that our breathing is regulated by the amount of CO2 in our bloodstream, not the amount of oxygen. There is a fantastic explanation of the danger here: https://blog.daneurope.org/en_US/blog/are-full-face-snorkeling-masks-dangerous https://blog.daneurope.org/en_US/blog/are-full-face-snorkeli... There are safety regulations to limit the volume of air inside a snorkel (the dead space). "Snorkels constitute respiratory dead space. When the user takes in a fresh breath, some of the previously exhaled air which remains in the snorkel is inhaled again, reducing the amount of fresh air in the inhaled volume, and increasing the risk of a buildup of carbon dioxide in the blood, which can result in hypercapnia. The greater the volume of the tube, or the smaller the tidal volume of breathing, the more this problem is exacerbated." —https://en.wikipedia.org/wiki/Snorkel_(swimming) https://en.wikipedia.org/wiki/Snorkel_(swimming)
- bscphil 5y ago
  > When the user takes in a fresh breath, some of the previously exhaled air which remains in the snorkel is inhaled again For a long snorkel, you would want to exhale through your nose.

robocat 5y ago

That was dangerous due to the risk of hypercapnia: "increased CO2 levels could lead to unconsciousness which, if happening while in the water, can result in drowning.". Note that our breathing is regulated by the amount of CO2 in our bloodstream, not the amount of oxygen. There is a fantastic explanation of the danger here: https://blog.daneurope.org/en_US/blog/are-full-face-snorkeling-masks-dangerous https://blog.daneurope.org/en_US/blog/are-full-face-snorkeli... There are safety regulations to limit the volume of air inside a snorkel (the dead space). "Snorkels constitute respiratory dead space. When the user takes in a fresh breath, some of the previously exhaled air which remains in the snorkel is inhaled again, reducing the amount of fresh air in the inhaled volume, and increasing the risk of a buildup of carbon dioxide in the blood, which can result in hypercapnia. The greater the volume of the tube, or the smaller the tidal volume of breathing, the more this problem is exacerbated." —https://en.wikipedia.org/wiki/Snorkel_(swimming) https://en.wikipedia.org/wiki/Snorkel_(swimming)

bscphil 5y ago
> When the user takes in a fresh breath, some of the previously exhaled air which remains in the snorkel is inhaled again For a long snorkel, you would want to exhale through your nose.