Home | Crosswords | Word Searches | Flash Cards | Verbs | Songs | Creative Writing | Work Sheets | Phonics | ABCs Potion Book | Spell Book | ESL for Adults | ESL Articles| Lesson Plans | Scott Foresman ESL | Jobs | Web Guide
The Lights and Switches Riddle
Materials for Download: Lights and Switches
This is a simple open-ended puzzle. There are many possible solutions and even the 'canonical' solution is somewhat fraught with uncertainty. This is a small group free talking activity.
The teacher can introduce the riddle in any number of ways. I usually have one or two students read the riddle quietly and then explain it to the other students. When I am satisified the students have communicated the riddle and that all of the other students have understood it, then I ask them to come up with solutions.
The canonical solution is to turn one switch on and then wait. Turn that switch off. Turn a second switch on and go into the other room. The light that is on is the second switch. The light that is off but warm is the first switch. The light that is off and cold is the third switch. Note the repetitive use of relative clauses (in italics) as a way of being precise. Also, 'first', 'second' and 'third' are used to keep track of the switches.
Other Riddles Lessons Available for Download
(worksheet only)
(worksheet only)
(worksheet only)
(worksheet only)
But this is not the only solution. And it's not even perfect: What if the light bulbs are so high up that you can't touch them? What if the light bulbs are of the kind that don't generate heat? What if the room is far away so that the light bulb cools down in the mean time?
At this point, the students debate the merits of the various solutions that they have come up with. I tend to be hands off and let them run the show, only interrupting to clarify a point of English or two.
Finally, I give them the canonical solution (if they haven't already got it) and tell them it's not perfect. In turns, each student will retell the solution to the riddle. I interrupt them and make them do it over again until they get it perfect, using all of the relative clauses correctly. Since I only use these riddles with small groups, it is possible to give this much individual attention. It is highly motivating and the students are happy to be able to produce such lengthy amounts of English at once.
Also see: Using riddles to Teach the Language of Logic and Precision by Yoda Schmidt. An ESL/EFL article.