 How have temperatures changed around the world? Students use trigonometric functions to model temperature changes during the year at different locations around the globe. They also compare their models based on past years’ data to current temperature trends. In the end, they discuss the advantages and disadvantages of modeling temperature with sinusoids and explore how the climate has changed in various cities over time.

### Students will

• Model annual temperature change in different world capitals using sine waves
• Make weather predictions using sine waves and calculate mean average deviation between predicted and actual temperature data
• Compare temperature models obtained using different data sets
• Discuss implications of global climate change

### Before you begin

Students should be familiar with basic properties of trigonometric functions (e.g. they should know that sin(x) has a period of 2π, a maximum value of 1, and a minimum value of -1). They should also be able to evaluate sin(x) at different values of x, either with a calculator or by hand (in special cases). Familiarity with how graphs shift under translation will also be useful; for example, it’s helpful if students know that the graph of f(x) + k is the graph of f(x) shifted vertically by the value k.