For my introductory deep dive, Tim decided to make things a bit more interesting and took down a raw egg to show the effects of water pressure. On the surface, air pressure = 1 atm (atmospheres). For every 10 metres depth, the effect of the water pressing down on us increases by another 1 atm, so at 30 metres depth the pressure is 4 atm. What this means is that an egg, cracked at a deep enough depth, will retain its round yolky shape in the water. Like so.
It was quite an interesting science lesson, and it was quite fun to bat the yolk ball back and forth between us. Unfortunately, we got a bit overenthusiastic and after a while the water pressure was unable to compete against the squishy strength of our hands. The yolk broke and made quite a mess in the water.
Lesson over, we got round to some nice diving. One of my favourite photographic subjects are pufferfish. There was a nice specimen hugging the reef that day.
It always cracks me up to see pufferfish. It’s hard to imagine funnier-looking fish. And if you ever imagined a football swimming through the water, that’s how they swim. We also came across a juvenile boxfish, which is part of the same family as the pufferfish. The poor little guy was petrified by us, and did its best to hide in the coral for protection. When he grows up, he isn’t going to be much bigger either!