ScienceMakers Toolkit Manual - The History Makers

greater than the can is able to withstand. You can crush an open aluminum can with your hand. When you
squeeze the can, the pressure outside becomes greater than the pressure inside. If you squeeze hard enough, the
can collapses. Usually, the air pressure inside an open can is the same as the pressure outside. However, in this
experiment, the air was driven out of the can and replaced by water vapor. When the water vapor condensed, the
pressure inside the can became much less than the air pressure outside. Then the air outside crushed the can.
When the water vapor inside the can condensed, the can was empty. You may have expected the water in the
pan to fi ll the can through the hole in the can. Some water from the pan may do this. However, the water cannot
fl ow into the can fast enough to fi ll the can before the air outside crushes it.
CAUTION: Do not heat the can over high heat or heat the can when it is empty. This may cause the ink on
the can to burn or the aluminum to melt.
For additional information:
CHEMICAL DEMONSTRATIONS: A Handbook for Teachers of Chemistry, Volume 2, by Bassam Z.
Shakhashiri, The University of Wisconsin Press, 2537 Daniels Street, Madison, Wisconsin 53704.
Find this experiment online at: http://scifun.org/HomeExpts/COLLAPSE.html
Darnell Diggs - Video Clip Transcription
Clip 1 - Changing Majors: I had a physical science course with a NASA physicist, his name was Donald
Hodge, and I was excelling in his course and he was like, “Are you sure you’re in the right discipline?” And he
was like “If I try physics, if I give you a scholarship, will you try it?” And I told him yes, and that’s how I got
into physics… Scholarship, but I think it’s more for minority students, getting minority students into the STEM
disciplines, when I say STEM, it’s science, technology, engineering, math. So, it wasn’t an academic scholarship
but it was money available to major in physics…I didn’t have physics in high school, so I didn’t know
what it was, I didn’t know what I was declaring as a major. Then I took it and I felt it - actually I got a D on my
transcript but I failed the course, but we had a comprehensive exam, and my professor was like, “Okay, whatever
you make on the comprehensive exam, I will give you that grade,” so I made a 61 on it and that was equivalent
to a D at the time, that’s what I have on my transcript. He said perhaps I need to change my major because
nobody will hire anybody that’s dumb…I knew I wasn’t dumb, I mean, it was a different subject matter, it was a
different way of thinking and going through high school, high school wasn’t as diffi cult but physics was something
different, I had to think differently so I had to sit down and you know, look inside myself and know that I
could do it. But then I took it again and got a C which is really not, it was some improvement from an F to a C,
then I went to the second part and got a B, then my grades started to incline.
Clip 2 - Experience with Physicists: I did not know any physicists, although I met one later on at the church I
was going to. Dr. Paul Ruthford who is now an S.T., a senior scientist, which is equivalent to a general for the
Army, he’s a physicist, so I saw him…Then when I joined the Physics Department and started going to the National
Conference of Black Physicists, National Conference of Black Physics Students, or heard of people like
Shirley Ann Jackson, who was the fi rst black woman to receive a Ph.D., it just happened to be in physics from
MIT, and now she’s the highest-paid college president in the nation at RPI, Rensselaer Polytechnic Institute.
They had a conference, they would fl y us in every year to promote African Americans in science and engineering…When
I went to the conferences and saw that there is a community of African American physicists, then
I knew then that is reality…I met Bill Gates, I met Keith Jackson… not the Microsoft Bill Gates, this is the
black physicist, interesting hairstyle, University of Maryland, College Park, string theory guy. I met him during
a tutorial on quantum mechanics and he’s brilliant, as a matter of fact I always credit him in terms of helping
me pass my qualifi ers for the Ph.D. There’s an exam you have to take in order to be a Ph.D. candidate, and you
only have two tries. If you fail it, then you have to go into another discipline. But he broke quantum mechanics
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Physics