Wednesday, August 8, 2007

News Flash! Common Garden Hose Shows The Earth is Really, Really Old!

Interviewer (yeah, really me, talking to myself) So what's all this then?

Cris: Well, I had this epiphany while watering my goats....

Interviewer: Um, does it involve any burning bushes or signs from Heaven?

Cris: No, nothing of that sort. You see, I turned on the hose, and it has a leak, you see. A little leak. I've tried to fix it, but it sprung another leak. It's had this leak for ages.

The hose in question

Interviewer: Okaaay...and this has what to do with geology?

Cris: Well, I live in Southern California. The ground is really, really hard here. Harder than lots of sedimentary rocks. So hard you need a backhoe to dig your garden. I could spend all day with a shovel and never get anywhere, certainly not to China.

Interviewer: That's a bit geological, then. Is there more?

Cris: Of course, we haven't even gotten to the best part! You see, the water comes out of the leak pretty slowly, and the hose is only on for 5-10 minutes at a time. But look at the canyon it's carved! I predict that, in 4.7 million years, if I let the hose trickle all the time, I could have the Grand Canyon in my backyard. But I think my husband would complain about the water bill.
Jamul Canyon

Wow, look at that steep bank!

The real Grand Canyon
Interviewer: That really does look a bit like the Grand Canyon in miniature. Why not just bring in a big tanker truck full of water and let it all loose here? Then you might at least have enough of a canyon to go whitewater rafting in.

Cris: I don't think that would work too well. I think if you dump out all the water at once, it won't carve a nice canyon. It will spread out over the ground and drain away. It might form some small channels, but not the Grand Canyon. Here, let's try it. OK, I have a large volume of water here, scientifically equal to the amount necessary to fill one empty Tidy Cat container. So here comes the deluge! Thunder and lightning please!
Experimental apparatus
The flood begins!
Aftermath of the flood

A closeup

Interviewer: Hmm, that doesn't look like the Grand Canyon at all, does it?

Cris: Not at all. It does look a bit like the area surrounding Mt. St. Helens, though.
Mt. St. Helens

Interviewer: That it does.

Cris: Well, I am just glad that a leaky old garden hose could give such an eloquent lesson in geology.

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