Cooling Cup of Coffee

Introduction

Take the temperature of a cup of coffee at regular intervals. How can you fit an exponential curve to the data? This is a classic exploration, think carefully how you can put your own spin on this.

Guiding Questions

• Measure the temperature of a cooling drink every minute. What does the graph look like?
• Fit Newton's law of cooling — an exponential approach to room temperature. How good is the fit?
• What is the cooling constant for your cup, and how does it change with a lid, a different cup, or stirring?
• Use your model to answer a practical question: when should you add the milk?