Re: Falling Feather -- largest tube that can be used

From: Ron Hipschman (ronh)
Date: Tue Jan 27 1998 - 14:31:23 PST

You can create a "reasonable vacuum" with any pump given enough time. If the
inside diameter of your tube is large, it will take you longer to pump out
the tube. This is assumming that you have good seals. If you have leaks, you
will never be able to pump it down, so be REAL careful there. One other
possible consideration would be that with larger diameter tubes, you will
need a thicker-walled tube to keep it from collapsing from the outside
atmospheric pressure. Good luck!


> Date: Fri, 23 Jan 1998 20:10:14 -0800
> From: Ira Kaplan <>
> To:
> Subject: Falling Feather -- largest tube that can be used
> Hello. I am helping my son assemble the "Falling Feather" experiment and
> will be using the MightyVac manual vacuum pump. What is the largest
> tube we can use and still create a reasonable vacuum using the
> MightyVac? We plan to use a 6 foot long tube with a 3 or 4 inch inside
> diameter. Thanks.
> Ira and Joshua Kaplan, New Jersey

Ron Hipschman, Exploratorium, 3601 Lyon Street, San Francisco, CA  94123
                (415) 563-7337   (415) 739-5052 (pager)

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