30 September 1997: Fred Schaal [Lane Tech HS]
Fred commented that there was an opinion that the Moon Walk -etc was a fake. The trajectories were not appropriate for a vacuum. It was pointed out that there were other views on tape that showed the actions better than the ones on the news.  For details see http://pirlwww.lpl.arizona.edu/~jscotti/NOT_faked/moon.htm.

The trajectory of a ball on earth---with wind resistance---and on the moon are quite different. The section of ellipse that would show what happens on the moon is shorted on the earth. An 800 foot home run would become 400 on earth. Porter suggested that a ball hit in Denver will travel further than one hit at Boston (sea level). In soccer the term "Banana Kick" is used to describe the altered path. [For a discussion of the physics of soccer, see http://www.madsci.org/posts/archives/nov98/912136446.Ph.r.html. Also in golf the dimples cause turbulence and make the ball go further.

30 September 1997: Fred Schaal [Lane Tech HS]
raised the question of whether NASA tapes of the moon landing could be used to prove/disprove to skeptics that the moon had no atmosphere and reduced gravity. For instance, during the filming of the take-off of the lunar module, is it evident from the dust pattern that they were on the moon? Porter Johnson suggested that the best evidence might come from a study of the trajectory of the golf ball, which should be truly parabolic on the moon, with no possibilities of a slice, no effect of back-spin, etc. Air resistance is very important for the flight of a golf ball on earth, in contrast to on the moon.

14 September 1999: Bill Colson [Morgan Park HS]
placed a disk on a phonograph turntable; the disk was a black-on-white drawing of an inward spiral (actually three spirals). As it rotated it gave the impression of a whirlpool spiraling inward. Bill told us to concentrate our gaze at its center for a while, then to look at one of two pictures he had on display. When we did this, the images in the pictures appeared to move. One was the "expanding universe," and the other of "clouds." Quite a sensory illusion! Of course, this leads to questions about what goes on in our vision and brain to lead to such effects? Any ideas? Bill passed out a 1981 paper, "The Jerry Andrus Tri-Zonal Space Warper", which described what he showed us, and more.  See the website http://www.grand-illusions.com/opticalillusions/pinwheel/.

28 September 1999: Ken Schug (IIT)
showed and passed around a most curious experiment. He mounted in a small box (about 3x6 sq in), a piece of paper two lines of the same words, one line directly below the other. Each line read: URANIUM OXIDE, but on the top line the word OXIDE was printed in red and in the bottom line, blue. We took turns viewing the words through a glass rod, about 3/8 inches diameter and 3 inches long, held on the paper, in direct contact with one line of words. When we moved the rod down to the line below, we were amazed to see that ...

18 November 2003: Marilynn Stone [Lane Tech HS,  Physics]        Optical Illusions
Marilynn showed a stationary image of intermeshed gears on her lap-top computer. To many of us, the gears appeared to rotate when viewed close up.  This was a novel type of optical illusion, which we all enjoyed looking at.  When our eyes are not focused, and when we view it from the side, it appears to be stationary. However, when the central part is focused upon, the outer portions seem to rotate.  Isn't this remarkable?

To see the picture, look at the image Rotating Snakes on the website: A. Kitaoka: The Latest Works:  http://www.ritsumei.ac.jp/~akitaoka/saishin-e.html.

Thanks, Marilynn!

04 May 2004: Sally Hill [Clemente HS, Dean of Students]           Optical Illusions
Sally passed around a set of optical illusions which she has assembled,. She uses them in her new position to put parents and visitors at ease.  Here is a partial list of the titles of the various illusions:

• Do you see four people? (Image of older man with beard).
• Who's the tallest?  (Believe it or not, these guys are all the same height!)
• A face -- or, the word  LIAR
• What do you see here?  Do you see the word LIFT? Or, a bunch of black splotches?
• How many horses in this picture? (The Answer is 7.)
• Look at the middle column.  Where does it end?
• Impossible Object --- like Escher
• There are 11 human faces in the picture.  Can you find them all?
• Focus on the dot in the center and move your head backwards and forwards.  Weird Hey!

Several of these illusions are available on the BAM Magic Club website:  http://www.mandrgames.com/illusions.htm.  

Thanks for sharing these with us, Sally!