BCR: Which Towel?
A student asks a testable question: “Which brand of paper towel absorbs the greatest volume of water?”
Design an investigation to provide an answer for the student. Be sure to include
• the materials needed.
• a numbered procedure.
• the independent and dependent variables.
• important data that will answer the question.
• ways to help ensure the accuracy of the results.
Materials: Several paper towels, a flat dish, bottled water, a thermometer, a tong, a ruler, and an scale,
(1) Weigh the sick + water
(2) Measure each sample of paper towel to be tested to assure a common size and weight. (3) Measure the temperature of the water.
(4) Add the towel sample to the water for a period of time using a consistent method. (5) Remove the sample from the water with a tong and allow excess water to leave the sample. (6) Measure the weight of both the wet paper towel sample and the flat dish Independent and Dependent Variables:
The dependent variable is the water absorbing capacity of the paper samples, and the independent variable is the weight of water captured by each paper sample. Important Data: The weight of the water trapped by each paper sample. Ways to Ensure Accuracy: Each measurement should be checked for accuracy at least twice by one or more observers, and each paper towel brand should be tested 2-3 times, using new paper samples each trial.
BCR: The Balloon
A balloon is placed over an empty flask. The flask is heated on a hot plate and then cooled in a container of ice water. The effect on the balloon is shown in the diagram below:
Explain this observation based on the Kinetic Molecular Theory. In your response, be sure to
• describe the effect of temperature on the kinetic energy of the gas particles. • describe the motion of the gas particles.
• describe the effects of this change on the pressure and volume of the gas sample. When temperature increases, the...
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