Orchid Classes Visit

Last week Orchid class had the rare treat of having a visit from a polar diver! His name was Simon Holebeach, and he told us all about buoyancy. So then, here is all about buoyancy, and then I will tell you more about our day…


Buoyancy (or upthrust) is a force that occurs when the weight of a submerged object is pushed up (or down) by the force of the water that is beneath it. For example, if you take a tennis ball and drop it in water it will go straight back up. This is buoyancy. Because the weight of the tennis ball has been pushed upward by the power of the water. I hope this has been helpful.

Going Up!

With diving you always have to come up to the surface right? However on some dives (mostly deep ones) you have to be very careful when coming up, or you’ll get what’s called ‘The Bends’. This is where if you go up too fast then gas bubbles will form and grow in your body, so if you got one in your elbow, it would really hurt and you would bend it etc. Anyway that is getting off the subject. when your going up in a dive then you would want to release weight, and you can’t just go and drop some weight in the local gym can you? So then the diver would have to release oxygen from their suit through a valve, or they could drop weights that they already have on them.

Going Down (again)!

When diving and you want to go down (or stay at that level of the sea) then you would have to basically pick up weight so rocks etc.

The Rest Of our Day

Once we had learnt about buoyancy, Simon got us to make or own diver buoyancy thingy! it was actually part of a cut pippete with blu-tac on it in a bottle, but when you squeezed it it when down and up! But I wasn’t just like that. You had to test that your ‘diver’ would float in water, then put it in and test it (it took me a LOT of time!). After that was done we then got to try on Simons diving suit, it was massive!

A polar diver.



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