A FEW SUGGESTIONS FOR TESTING IN HIGH-SCHOOL CHEMISTRY G . ALBERTCOOK,SENIOR HIGHSCHOOL, ANN ARBOR, M~CHIOAN
One problem the high-school chemistry teacher faces is that of testing the pupils' memory of the properties of numerous substances. The following method has been found very successful: Directions.-Check Ch
all the appropriate properties:
Na
N1
HNOI
h
() ( 1 ( )
() ( ) ( )
( ) ( ) ( )
( ( ) ( 1
( ) () ( )
gas at room temperature strong acid metal
( ) ( ) ( )
( ) ( ) ( )
( ) ( ) ( )
() ( ) ( )
() ( ) ( )
component of the air ~oisonousgas forms base after reaction with water
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Method of Marking.-Each group of three parentheses counts one point; . a mistake in a group takes off the whole point. The f i s t time the students have a question like this on a test, i t 'should be made clear to them that they are to start with the first substance; e. g., chlorine, and look at each property (in the right-hand list) in turn to see whether it applies to that substance. If it does, a check-mark should be placed in the parentheses under the substance and opposite the correct property; if Got, the parentheses should be left vacant. The purpose of barking the responses in groups of three is this: the chance of guessing whether or not to put a check mark in any pair of parentheses is just one-half; by the theory of probability, the chance of guessing correctly all three of a group would be one-eighth. It is a safe rule to have the guessing chance less than one in five, so this method is perfectly safe. The same idea can be applied to the true-false method. I have found that in chemistry there are a great many items to test which involve only two alternatives. These can be tested by brief statements, with directions to mark T for true and F for false. These statements are placed in groups of three on the mimeographed test, and are marked that way, the whole group being counted wrong if a single statement is incorrectly designated. If the reason for this is explained to the pupils, there will be no trouble on that score. Pupils rather like the true-false method. Of course, it would not be a good plan to have very many such groups. The greater the variety of the methods of testing on a single test, the more interesting it becomes for the pupil to take. It is probably not a good plan to use exclusively these new-type methods of testing. At the bottom of the mimeographed sheet, I have found it a good plan to have a statement like the following:
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VOL.5, NO. 10
Succ~srro~s *OK TESTING IN CHEMISTRY
1273
"On the extra (blank) sheet given you, h s t write your name, then write out: 1. The distinctions between a compound and a mixture. 2. etc." In this way the pupils still get some writing to do, but not so much as to burden the teacher with wading through a sheaf of the old-type test "blue-books."
