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A Watched Cup Never Cools Class Project. When you have a hot cup of coffee, how long does it take until the liquid in the cup reaches room temperature?. You might be surprised by the answer to this question.
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A Watched Cup Never CoolsClass Project • When you have a hot cup of coffee, how long does it take until the liquid in the cup reaches room temperature?
You might be surprised by the answer to this question. • In this activity you will discover the mathematical relationship that describes how a cup of hot water cools.
PART 1 • Fill a cup or a mug with water. • Hit the water to near boiling, about two or three minutes in a microwave oven. • Wait minute or two for the cup to heat as well. • Record the room temperature. • Record the temperature of the water over the next three or more hours as it cools. • Be sure the thermometer or temperature probe is in the water, not touching the cup bottom or wall . • Enter these data points (or a subset of them) into your calculator and graph them.
PART 2 • Find an equation that best fits your data. • Examine the residuals to help fine tune your equation.
PART 3 • Determine the slope between two data points. • These slope values give the rate of cooling in degrees per unit time. • How does it change? Graph this rate of cooling. • Explain how you determined your graph. • Describe any relationship you see between this graph and the graph of the original data.
PART 4 • Alter the data by subtracting room temperature from each temperature measurement. • Find the percent change in temperature per minute and graph this. • Explain the appearance of the graph. Does this give you any additional insight?