A cylindrical lens appears to invert the word SULPHUR but not DIOXIDE.
Both sulfur and sulphur are accepted these days, but sulfur is now preferred in most places.
Note the demonstration works well with CARBON DIOXIDE as well.
Really just fun, but it does help to illustrate the concept of symmetry and also helps develop critical thinking and problem solving skills.
NCEA & Science Curriculum
SCI 1.3, PHYS 1.4, PHYS 2.3
Ask students why SULPHUR is inverted but dioxide is not. Suggest dispersion (ask what prism does). Try to convince them that the cylindrical lens inverts the blue word but not the red word because the refractive index of the magic liquid (water) is larger for blue. Then admit it’s all untrue and show that DIOXIDE looks the same if flipped. You can prove the point by adding a small bit of Blu-Tack to the top of one of the letters in DIOXIDE and it will appear at the bottom when viewed through the lens.
This can be done with a Perspex or glass rod. This version which is about a meter long, is suitable for a somewhat larger class.
Individual teachers are responsible for safety in their own classes. Even familiar demonstrations should be practised and safety-checked by individual teachers before they are used in a classroom.
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