Explorers

In January 2012 the Explorers spent a session discovering that while light travels in a straight-lined path, it is still possible to see around corners. This of course raises all sorts of possibilities in the realm of student espionage!

Using a pocket laser and a couple of mirrors, the students successfully demonstrated that a beam of light can be bounced, or “reflected,” in different directions. One student reflected the laser dot 90 degrees to one side by tilting the mirror. A second student was then able to use another mirror to bounce the laser beam back into its original direction of travel. So, even though the path straight to the classroom’s white board was blocked by an obstacle (a student), the laser beam still managed to bounce its way around the obstacle and hit the board—just a little ways to the side of where the direct path would have ended up.

Bouncing a laser beam around is kind of cool, but does this actually show anything useful? Well, any other ray of light can be manipulated the same way—so rather than sending a beam of light in another direction, you can use mirrors to direct the light coming TOWARD you onto a different path. This concept is behind the device known as a periscope, used to great effect by submarine captains who need to see the ocean’s surface even when their vessel is completely submerged. A long tube pokes above the water’s surface, and a pair of mirrors reflects the light—and the view—f rom above down into the sub’s control room.

Now the students set out to create periscopes of their own. They might not have a reason to use them underwater, but perhaps some other sneaky opportunities might present themselves. After all, who knows when one might need to peek around a corner to spy on a brother, sister, or pet? (Parents, of course, are off-limits to this sort of thing—no student would even DREAM of using it to watch Mom or Dad. No, not at all.)

The Explorers began by tracing a rather complicated pattern onto some sheets of posterboard. When cut out, these patterns could then be folded into a strange sort of box. It was long and narrow and open at both ends, but with openings facing out toward the front and back (if the box was stood up vertically). Also, both openings had tilted surfaces.

When the boxes were all folded and taped together, it was time to add the mirrors. Each box needed a pair of mirrors, and they were attached to the tilted surfaces (with a hot glue gun wielded by Mr. Ramsey) at the opposite ends of the box. Now a beam of light that entered one opening of the box would be bounced “down” by the first mirror to the other end, where the second mirror would then bounce it back out the way it had been originally going. Putting your eyes to this second opening would allow you to see the light that came in through the first opening.

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Mr. Ramsey left the students with one word of warning—the craft mirrors used for this project can sometimes have sharp edges. If a mirror gets knocked free of the periscope it can be fastened in place again with another hot glue gun, but you need to be careful handling it.

To read more about a previous year’s session with this activity, click the link below. To see some photos of our secret agent periscope-making fun, check out the Gallery. Special thanks to Mr. and Mrs. Marshall for taking some additional photos for us—and as always, thanks to our club assistant Lissa. This is one activity that takes too much supervision and assistance for one person to handle, so we would not even TRY it without her help!

Earlier Periscopes