Ring of Fire

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The red ring has lasers that make a plane of light. The lasers are eye-safe, but nevertheless people should not stare directly at them. Kids may find it neat to put their hands in the ring, and that is just fine.

Participants can pick up any one of several objects and hold them in the laser ring to see their cross-sections. Rotating the object and moving it in and out can give different shaped cross-sections. Here are some challenges you can give the participants:

  • Cylinder: Find a circle, a rectangle, an ellipse, and half an ellipse. You can also ask them to find a very thin rectangle, that looks almost like a line segment.
  • Cone: Find all the conic sections: circle, ellipse, parabola, hyperbola (one branch), and a pair of lines.
  • Cube: Find a square, rectangles, triangles (both irregular and equilateral), and a regular hexagon. The hexagon is the hardest one to find. The trick is to have the laser plane go through six edge midpoints.
  • Tetrahedron: Find a triangle, a rectangle, and a square. The square is the hardest; the trick is to have the laser plane go through four edge midpoints.
  • Dodecahedron: Find a triangle, an equilateral triangle, a rectangle, a square, a pentagon, a hexagon, and a decagon.

There is also a plastic model of a human. Let the visitors find different cross-sections as they move the figure through the laser plane.

The lasers can become misaligned if banged. Feel free to adjust them -- simply aim each laser at the lasers on the opposite side of the ring.

Please Note

The objects are made of polycarbonate and are weakest at the joints. They can break if dropped. Please make sure that participants use the objects only within the laser ring -- the objects should not be tossed around or removed from the area.

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Ring of Fire
Ring of Fire
Ring of Fire
Ring of Fire