people that float...

[Bettina]

I work at the park teaching little kids to swim, play tennis, etc.

 

In the pool, I have them floating on their backs for example. Two same size kids. Holding there breaths, one floats easily but the other struggles. No matter how much air he takes in he has a tough time.

 

Why?

 

Bettina

[DQW]

Different densities, that's all. Different ratios of bone tissue to muscle tissue to fat, I guess.

[Dak]

i sink like a brick, and can sit on the bottom of a swimming pool with a lung full of air; i also have a below-average body-fat index.

 

anecdotal i know, but there you go.

[Phi for All]

Perhaps the struggling is from a fear of the water. Is he sinking and that's why he struggles? Or is it that he's too rigid and not relaxed enough to keep his head out of the water?

 

Pockets full of nickels?

 

Pseudoscientifically, maybe HE'S A WITCH!!!

[Dak]

^^^ no. witches float, not sink. if he sinks, hes not a witch.

 

the one who floats is a witch.

 

or a duk. they float too.

[coquina]

True - it's easier for some people to float than others. I can float on my back with my hands under my head and my legs crossed, and I have a heck of a time diving to the bottom when snorkeling - even with flippers.

 

One trick to floating easily is to put your head back in the water until it almost comes up to your eyebrows.

[Phi for All]

One trick to floating easily is to put your head back in the water until it almost comes up to your eyebrows.

Yes, this is what I meant earlier when I asked about his struggling. If the child is not comfortable relaxing enough to put his head back (I worded it poorly before) he may not be giving himself a chance to achieve bouyancy.

[J.C.MacSwell]

i sink like a brick' date=' and can sit on the bottom of a swimming pool with a lung full of air; i also have a below-average body-fat index.

 

anecdotal i know, but there you go.[/quote']

 

Me too twenty years ago and now I float no problem. Subtle change in my floating style I guess, couldn't have anything to do with twenty years of donuts!

[insane_alien]

I can float and i can sink. if i tense my mucles up so the contract i'll go under but if i relax i can float quite easily. kinda like a submarine. fat kids float the best. i work as a life guard in a pool and you get bored if its quite and you notice strange things like that.

[Sayonara]

Something to do with different kinds of muscle fibres I think. I will ask Punchy Dave - he sinks like a stone.

[Bettina]

I made all the kids float today as a test. I had 7 of them and 5 float easily. The other two just can't. I had a helper with me so I concentrated on the two. They still struggle (struggle to stay afloat...not panic) even when I'm holding them from sinking.

 

None of them looked like they had more fat than the others....all pretty lean and the same height. The two that can't are both boys if that makes a difference.

 

Tommorrow I'm going to have them all blow into balloons to see if the other 5 have more lung capacity, only I'm not sure how to measure it. I'm betting on that. I will let you know.

 

Bettina

[Sayonara]

Dave said:

I told you before, it's all about density (obviously) but more specifically types of muscle fibres. See, I have a generous helping of fast twitch muscle fibres which makes me an excellent candidate for sprinting and weightlifting and suchlike. Consequently it makes me a dreadful swimmer, as no matter how much air I have in my lungs I'm always battling to stay afloat. I don't think lung capacity is an issue because mine is well above average.

To bring in a completely non scientific analogy, observe how many world class sprinters are black, and then how many world class swimmers are white... the obvious conclusion? My negative bouyancy is due to me being a black man trapped in a white mans body... it also explains why I'm such a good dancer.

Wikipedia has some info, but doesn't mention density:

http://en.wikipedia.org/wiki/Muscle_fibre

[coquina]

Somewhere I read/heard that the problem is specifically in the density of the legs - especially if the person has long ones without much fat on them. The legs sink and pull the rest of the body down.

[Jacques]

I am one of them with long leg and that's what I experience: my leg sinking pulling the rest of my body down.

[Nevermore]

...None of them looked like they had more fat than the others....all pretty lean and the same height. The two that can't are both boys if that makes a difference....

Bettina

Fat is lighter than water. The fatter you are, the more boyant you are.

Muscle and bone sink.

[aswokei]

Dak, you female or male?

 

It's actually the same thing for me. When I let out the air, I just sink quicker. Swimming takes a lot of energy for me.

 

My body fat percentage is less than average even though my BMI tells me I'm overweight. I guess it's all the weight lifting I've been doing since I started college.

[Sayonara]

BMI turns into utter bollocks very quickly if you put on muscle.

[MetaFrizzics]

BMI turns into utter bollocks very quickly if you put on muscle.

Wow. I thought your bollocks actually shrank when you did body-building!

[J.C.MacSwell]

Wow. I thought your bollocks actually shrank when you did body-building!

 

Only with "supplements"!

[Bettina]

Well, I gave up with the balloon idea. I had them all take a deep breath and blow into the balloons, but they all were pretty much the same, and I didn't have a good way to measure the diameters....coupled with the fact that they weren't interested enough.

 

So, we filled the rest of the balloons with water and had a fight.

 

When I came home, I found this which pretty much explains it all. You guys were right.

 

http://www.science.ca/askascientist/viewquestion.php?qID=1937

 

Bettina