Question

In the first step of the experiment, students are told that the 50 milliliter graduated cylinder should be filled with 43 1/5 milliliters of a liquid mixture. 2/3 of the mixture should be water, and 1/3 of the mixture should be of the unknown liquid. How many milliliters of each substance should be put in the graduated cylinder? Show all your calculations.Next, students are told that the liquid mixture they created in the first step should be divided evenly into the four 25 milliliter graduated cylinders. How many milliliters of the liquid mixture should be put into each 25 milliliter cylinder? Show all your calculations.In the final step, the four 25 milliliter graduated cylinders, each containing an equal amount of the liquid mixture, are lined up, and one drop of food coloring is added to the first cylinder. Students are then directed to transfer 2 milliliters of the colored solution from the first cylinder to the second cylinder; then, transfer another 4 milliliters of the colored solution from the first cylinder to the third cylinder; and, finally, transfer 6 milliliters of the colored solution from the first cylinder to the fourth cylinder. The students will then analyze and compare the intensity of color of the solutions in the four graduated cylinders. Do the instructions for the final step make sense? Explain your reasoning.

Answer 1

50 mm cylinder; to be filled with 43 1/5 mm of liquid mixture; 2/3 of water; 1/3 of unknown;

answer 1) 2/3 of water of a total of 43 1/5mm; that means (43.2) multiplied by 2/3: (43.2)x2/3 = 86.4/3 = 28.8 mm of water

1/3 of unknown of a total of 43.2mm; that means (43.2) muliplied by 1/3: (43.2)x1/3 = 43.2/3 = 14.4 mm of unknown

answer 2) If the total quantity of the original mixture is 43.2 mm, and it has to be divided evenly into 4 cylinders, they have to put 43.2/4 on each cylinder, 43.2/4 = 10.8 mm

answer 3) Each of the 4 cylinders have 10.8 mm of liquid, if they take the firs one and transfer 2 mm to the second cylinder, the first sylinder will be left with only 10.8 - 2 = 8.8 mm; then they take the first cylinder and transfer 4 mm to the third cylinder, so the first cylinder is left with 8.8-4 = 4.8mm of liquid; finally thay should transfer 6 mm from the first cylinder to the fouth... BUT THE FIRST CYLINDER ONLY HAS 4.8 mm OF LIQUID... It does not make sence