3 of 3 Items .... Source: Mathshell

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Here are six sets of containers. The water in the top one is draining into the bottom one at a constant rate. The puzzle here is to determine, at five intervals during the pour, what the surface of the water looks like when viewed from above.








Here are the possible choices. There is one set for the surface of the upper one and one set for the surface of the lower one. Some of these cards have missing pieces. Students need to draw those.










Print them from the source below.

source.

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Always True, Sometimes True, Never True?




Once again ... The why is the important part.

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Always True, Sometimes True, or Never True?



Cut out the cards and have students sort them into one of the three categories.

In each case, students need to say WHY its always true or NEVER true, or give an example and a counterexample for when it is SOMETIMES true.