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You ideas will help me if I get a teaching job.
BTW
Experiance has tuaght me that itis better to make an easy test than to curve a hard test. I need to know who has talent so there has to be many questions appropriate for students who have an IQ above 110 OR do their homework. To get the desired set of grades I need easy questions.
Here is an example.
First question on test.
Look at the graduated cylinder in the front of the room. Notice that the water level has been marked with a black line. Notice that thier is lots of ice below the line but there is also some ice above the line. 30 minutes from now after some of the ice melts will the water level be the same, higher, or lower?
This question can stimulate discussion the following day.
I will cover(before the test) the grad cylinder with plastic wrap to minimize evaporation. The next day when all the ice has melted they will see that the water level is still the same. Furthermore we can discuss the difference between floating icebergs melting and ice on land melting.
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The water level should stay the same.
But what would happen if you put some coins into the ice before and while the ice is melting the coins sink to the ground?
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Supose You have 3 exactly similar sets, which one including one party ballon, one string and one paper weight.
Take the first ballon, fill with air, tie a knot with the string so it doesn't leak, and tie the other end of the string to the paper weight.
Now you do the same with the second set, except that you fill the second ballon with helium.
And then again the same with the third set, but you leave the ballon empty.
Questions: which of the three sets is heavier? And which one is lighter?
Now put each set at a time on a precision scale. Are the results different from the previous questions? Why?
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Noroc and fernando...
These are great questions. I assure you that there are many 9th graders with an IQ of 100 or more that cant answer them correctly.
However there are many 9th graders with an IQ below 120 that will get them right.
You have shown that an addition to easy questions I also want questions that are doable but challanging to a typical 9th grader.
thanks again
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fernado's question could be miss inturpreted.
the weight without the precission scale refers to the material of the ballon. since the mass of the rubber that the balloon is made out of did not change the weight of the baloon did not change. when we add the scale we want to know the force pushing down on the scale. that includes the affect of the stuff in the balloon and the bouyant force. we assume the experiment is not done in a vacuum.
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