Explaining dive principles in SIMPLE terms

[Frosty]

Hey folks . as I asked in another thread all of my kids are wanting to at least give scuba a try.
The oldest lads are getting into the whole E learning experience so no problem.
The youngest(7) is keen to try being a bubble maker. Im working through basic scuba concepts with him in the most simplistic terms.
So far we have
1)A balloon filled down deep will BURST if you bring it to the top.-Your lungs are baloons so you must never hold your breath.
2)down deep you use LOTS more air than on the top.
3) dont touch anything
4) 20 underwater hand signals.
5) if you get sore ears go up a little bit.
6) red on the pressure gauge means danger

What do you think and what would you add to the list -Taking more complicated stuff and breaking it down to simple concepts

 

[DiveNav]

......1)A balloon filled down deep will BURST if you bring it to the top.-Your lungs are baloons so you must never hold your breath. ....

We have used this concept - and expanded it - in our introduction to dive computers online class.

We modeled into the ediving simulator an inflated balloon attached to a weight and measured it at the surface.
Then while free diving we brought the balloon/weight to the bottom and re-measured it showing that the balloon had shrunk - like the lung of the free diver. Then brought the balloon back to the surface and re-measured.

Then we repeated the process while scuba diving. But this time, when at depth we show that while the balloon has shrunk, the lungs have not since diver is breathing at ambient pressure.
Then - at the bottom - we inflate the balloon until the balloon/weight is neutrally buoyant. then we push it up a bit.
We then show the balloon ascending .... and accelerating ... and expanding ..... and ascending until it explodes.

No body got hurt because the whole sequence was done in the simulator

you can see a very brief sequence of what I described above in this video.

[video=youtube;TnFH5NWNTK0]http://www.youtube.com/watch?v=TnFH5NWNTK0[/video]​

the full sequence is in the introduction to dive computers online class

 

[RonFrank]

7 year olds can not dive yet..... there have not been much in the way of studies done on children who are developing and what impact diving has on them.

That said I think focus on ears and clearing. It is something that most divers have trouble with at some point. Telling them to go up until they can clear maybe enough. They should understand that clearing is NOT a scuba event. They can practice any time.

 

[Frosty]

7 year olds can not dive yet..... there have not been much in the way of studies done on children who are developing and what impact diving has on them.

That said I think focus on ears and clearing. It is something that most divers have trouble with at some point. Telling them to go up until they can clear maybe enough. They should understand that clearing is NOT a scuba event. They can practice any time.

Hi Ron-Just to be clear -he will NOT be doing "propper" scuba under any circumstances.The plan is for him to sit in the shallow end of the pool (3 feet deep) and breath through an octi reg or possibly even a pony bottle. This is the youngest of five kids and this 7 year old is happilly snorkle diving down to roughly 6 feet so other than an octi in his mouth nothing is any different than what he's already doing.
BUT he wants in on the training
Whilst he's really interested I figure no harm in introducing broad concepts and ideas.(as long as they are truth)

 

[j yaeger]

...if sponge bob and squidword can handle the safety concepts...
kids,so can you!!!
start them young
tell them the "whys"
let them have fun!!!
enjoy them
yaeg

 

[Tropicalwolf]

First, watch out for the safety police who are going to tell you what you can and can't do with your kids. Second, tell them NOT to pee in the wetsuit...let's raise a "better class" of future divers.

 

[Quero]

Oh, let 'em pee! No need to be prudish or call the "politeness police"--peeing in a wetsuit isn't a safety issue. Besides, it's easier to soak a wetsuit in Listerine overnight than it is to cure bladder problems that stem from telling people they have to "hold it" while they're in the open water or having people not drink enough fluids because they feel uncomfortable underwater trying to "hold it."

I work with Bubblemakers from time to time. Practical examples of physics principles are the way to go. If you can actually demonstrate a concept, that helps get the idea across.
1) By taking a closed up water bottle filled with air to the bottom of the pool and showing how it starts to get crushed, you demonstrate Boyle's Law.
2) When talking about mask clearing underwater, it's easy to show with a partly filled bottle that the water will always be "down" and the air will always be "up" so that if there's more air in the bottle, there will be less water. Getting the water out is a matter of getting more air in.
3) Teaching about ears--try to get him to be pro-active and pre-pressurize the ears so that they never get "sore". Take your car to the top of the highest hill around you and coast down, having your youngster pay attention to the sensations in his ears. Get him to say what he had to do to equalize the pressure in his ears (to make them "pop"). Then go back up, but pre-pressurize the ears at the top and have him see that there is no need to "pop" his ears on the way down this time.

 

[LowDrag]

Pre-pressurize? Never heard that one before Quero. Would you be willing to fill me in on how to do that please? Thanks.

 

[Quero]

It's my own made-up term, so maybe there's a more precise one floating around out there that makes more sense on first reading, but essentially it's simple. If you perform a Valsalva right now, sitting at your computer, you will push enough air into your middle ear through your eustachian tube to make the internal pressure greater than the ambient pressure of the surrounding air. If you do this on the surface of the water, before descending, during descent the pressure of the surrounding water will build until the ambient pressure and the internal pressure in the middle ear are equal. At that point, another Valsalva will pressurize the middle ear again, allowing for further descent. By taking care of equalization this way, pro-actively, rather than correcting a pressure imbalance reactively after the water pressure has created the imbalance, it's a lot easier to prevent ear injuries. IOW, when I recommend "pre-pressurizing," what I mean is to do a Valsalva on the surface and on every breath while descending to introduce more pressure into the middle ear than is present in the surrounding air or water.

Edit: RollinontheRvr, I now see that you are not certified, and realize that you may not know what a Valsalva is. It's just the name for pressurizing your ears by pinching your nostrils and lips shut, and then blowing gently, forcing air from your lungs into your head.

 

[highdesert]

Something I use when explaining BCs/buoyancy/weighting to non-divers:

Q: What happens to a rock when you throw it in the water? A: It sinks.

Q: What happens to a balloon when you put it in the water? A: It floats.

Q: Now what if you tie the balloon to the rock? A: Hmmm ....

Now I talk about varying the weight of the rock, or the volume of the balloon, until we hit the "sweet spot" where we neither sink nor float.

Most people have an "Aha!" moment when they are presented with this.