Today I decided to try a lesson on dowsing with a few classes, since it's the last week and we've finished the actual course.
Since I couldn't get hold of sticks or wire rods on short notice, I went with using a pendulum. I was quite impressed with the effect I got from it - when testing I got circular swinging over a can of water (actually swinging around the circumference a few centimetres above the can). When I then moved the pendulum away from the can it began swinging from vertical in the direction of the can itself. Even more interesting is that the swings changed direction toward the can even if I started it swinging perpendicular.
I introduced the idea by demonstrating these effects to the classes - all were suitably impressed - and I said I wasn't sure if it actually worked but had heard about it. The task of the class was then to try the effect themselves then try a proper experiment to see if it worked. I produced worksheets to this effect.
The first task was for them to try using a pendulum over an open water can, then to try again with a cover on the can. Almost all agreed that it worked well and suggested ideas like magnetism or the metal can attracting the pendulum.
Next they had to use three cans and verify that the effect only occurred over the one with water.
Then the tester had to move and look away from the table while their partner rearranged and covered the cans, then use the pendulum to work out which contained water. This test was repeated ten times and results recorded in a table, including whether each attempt was correct.
Finally I had the students calculate how many they would get right purely by chance (i.e. 1/3 of the ten = 3.33) and compare the results of the test with this figure, before suggesting any improvements to the method.
From two full classes almost all groups got three or four correct. One group got five. I then briefly discussed the results and talked about the ideomotor effect. Classes were both impressed and interested by the effect. My final point was about the importance of critical thinking and testing ideas for themselves.
Now this obviously wasn't a perfect experiment by any means, and the classes came up with plenty of suggestions such as using ten different cans, more repeats, etc. I was quite impressed.
Overall a far more succesful effort than my previous lesson on critical thinking - I'm now looking out for other ideas for this kind of lesson for the week. Please PM me if you have any suggestions, preferably for lessons without complicated resources.
Since I couldn't get hold of sticks or wire rods on short notice, I went with using a pendulum. I was quite impressed with the effect I got from it - when testing I got circular swinging over a can of water (actually swinging around the circumference a few centimetres above the can). When I then moved the pendulum away from the can it began swinging from vertical in the direction of the can itself. Even more interesting is that the swings changed direction toward the can even if I started it swinging perpendicular.
I introduced the idea by demonstrating these effects to the classes - all were suitably impressed - and I said I wasn't sure if it actually worked but had heard about it. The task of the class was then to try the effect themselves then try a proper experiment to see if it worked. I produced worksheets to this effect.
The first task was for them to try using a pendulum over an open water can, then to try again with a cover on the can. Almost all agreed that it worked well and suggested ideas like magnetism or the metal can attracting the pendulum.
Next they had to use three cans and verify that the effect only occurred over the one with water.
Then the tester had to move and look away from the table while their partner rearranged and covered the cans, then use the pendulum to work out which contained water. This test was repeated ten times and results recorded in a table, including whether each attempt was correct.
Finally I had the students calculate how many they would get right purely by chance (i.e. 1/3 of the ten = 3.33) and compare the results of the test with this figure, before suggesting any improvements to the method.
From two full classes almost all groups got three or four correct. One group got five. I then briefly discussed the results and talked about the ideomotor effect. Classes were both impressed and interested by the effect. My final point was about the importance of critical thinking and testing ideas for themselves.
Now this obviously wasn't a perfect experiment by any means, and the classes came up with plenty of suggestions such as using ten different cans, more repeats, etc. I was quite impressed.
Overall a far more succesful effort than my previous lesson on critical thinking - I'm now looking out for other ideas for this kind of lesson for the week. Please PM me if you have any suggestions, preferably for lessons without complicated resources.
