Water Slide Question

[Extravoice]

A while back, I went to a water park with my family. They had recently installed a new slide. It was simple, consisting of a single giant slide at a steep angle. The thing was very high, seemingly 4 or 5 stories. At the top, the view was very nice, and I figured it would be just as nice on the way down.

Preparing to decend the slide, the operator instructed each rider to place one ankle over the other, cross our arms across our chest and lie back. I did so, and proceeded down the slide.

To my surprise, I apparently fell faster than the water was flowing down the slide, and my foot created a cone of water that surrounded me as I decended. I saw absolutely nothing after the first few feet of the slide. It was very disappointing.

So, here is my question. Why would I decend faster than the water? I imagine that Mr. Gallileo might want to take a look at this device

[IsaacKuo]

Why would I decend faster than the water?

Drag. The water experiences drag against the slide. Indeed, the water is there mainly to prevent you from suffering much drag against the slide.

[Swift]

Drag. The water experiences drag against the slide. Indeed, the water is there mainly to prevent you from suffering much drag against the slide.

What he said. Gravity is powering your fall, the water is basically a lubricant.

[Jens]

Just to add a simple point, I'm pretty sure that in a river, the water flows faster at the surface than at the bottom, because the water at the bottom is basically acting as a lubricant for the water at the top (though of course it all mixes up). So there's nothing unusual happening.

[novaderrik]

way back when i was a teenager- way back in the late 80's- there was a slide just like that at an amusement park i used to go to a couple of times a year. us boys used to watch the girls in 2 piece swimsuits go down those slides.. some of them would get up and walk away and not even realize that the top part of their swimsuit wasn't actually covering the parts it was supposed to be covering after they got to the bottom.
that was the greatest show on earth when i was 13..

[Spoons]

way back when i was a teenager- way back in the late 80's- there was a slide just like that at an amusement park i used to go to a couple of times a year. us boys used to watch the girls in 2 piece swimsuits go down those slides.. some of them would get up and walk away and not even realize that the top part of their swimsuit wasn't actually covering the parts it was supposed to be covering after they got to the bottom.
that was the greatest show on earth when i was 13..

Yes, so to paraphrase novaderrik, the answer is friction.

[Extravoice]

Just to add a simple point, I'm pretty sure that in a river, the water flows faster at the surface than at the bottom, because the water at the bottom is basically acting as a lubricant for the water at the top (though of course it all mixes up). So there's nothing unusual happening.

After thinking about it on the drive to work this morning, I came to the same conclusion. Since my feet were crossed, my heel was cutting through the slower-moving water near the slide, resulting in the cone of water.

[NEOWatcher]

Since my feet were crossed, my heel was cutting through the slower-moving water near the slide, resulting in the cone of water.

There might be some effect there, but keeping the feet crossed has a more important reason. It keeps your legs together, preventing some very uncomfortable issues.

[Darrell]

Next time try this technique. Cross your legs one ankle over the other as you did. Put both hands behind your head, interlace your fingers and grasp your hands together firmly while holding your head up as if you were doing sit ups with your hands behind your head. Then flex your body and hold it as if you were doing an isometric exercise, such that the only parts making contact with the slide are your shoulder blades and one heel. Some friends and I perfected this technique one summer back in the 80's at Wet N Wild in Orlando. By far the fastest technique I know of.

[cjl]

Next time try this technique. Cross your legs one ankle over the other as you did. Put both hands behind your head, interlace your fingers and grasp your hands together firmly while holding your head up as if you were doing sit ups with your hands behind your head. Then flex your body and hold it as if you were doing an isometric exercise, such that the only parts making contact with the slide are your shoulder blades and one heel. Some friends and I perfected this technique one summer back in the 80's at Wet N Wild in Orlando. By far the fastest technique I know of.

You can do the same with your hands crossed over your chest (and your head still held up just with your neck muscles, so the only things contacting the slide are your heel and shoulder blades). You can really get moving, even on the non-speed oriented slides.

[pantaz]

Next time try this technique. Cross your legs one ankle over the other as you did. Put both hands behind your head, interlace your fingers and grasp your hands together firmly while holding your head up as if you were doing sit ups with your hands behind your head. Then flex your body and hold it as if you were doing an isometric exercise, such that the only parts making contact with the slide are your shoulder blades and one heel. Some friends and I perfected this technique one summer back in the 80's at Wet N Wild in Orlando. By far the fastest technique I know of.

I discovered a similar technique because my shorts were made of some material that would not slide (can't recall what it was). I had to lift my butt off the slide if I wanted to go anywhere!

[mugaliens]

I just go WWOOOHHHOOOO!!!!!!!! down the slide like a freakin' banshee and have boatloads of fun.

Uh, isn't that what we're supposed to do?

[JohnD]

After thinking about it on the drive to work this morning, I came to the same conclusion. Since my feet were crossed, my heel was cutting through the slower-moving water near the slide, resulting in the cone of water.

Eh? I had a sudden vision that this was you! http://www.youtube.com/watch?v=1WlRcXIO5ik

And neowatcher says, "There might be some effect there, but keeping the feet crossed has a more important reason. It keeps your legs together, preventing some very uncomfortable issues."
Do a google for "perineal injury waterslide": http://www.google.co.uk/#hl=en&q=per...f8fef19674b6f6

John

[Extravoice]

Eh? I had a sudden vision that this was you! http://www.youtube.com/watch?v=1WlRcXIO5ik

Thanks for sharing; that was pretty funny. I particularly like where he got stuck and had to scoot along.

[Darrell]

I just go WWOOOHHHOOOO!!!!!!!! down the slide like a freakin' banshee and have boatloads of fun.

Uh, isn't that what we're supposed to do?

What's not fun about going as fast as you can?

[JohnD]

On the mechanics of water slide, analyse this: http://www.youtube.com/watch?v=s1K0nwZP-Ag&NR=1
(the video, not the audio. The first is insane)
John