Students will explore daylights times of cities at different latitudes. They will create a scatterplot of the data and then find the cosine equation that matches the data. This should be worked in groups of 4, each student choosing a city of a different latitude.

An extension at the end would be for all students in the same group to graph their points on large poster paper so they can see what the similarities and differences are at the various latitudes.

If using an Nspire, students should be familiar with creating a scatterplot on the graph screen and then entering the function in the entry line.

If using a TI-84, the MS Word document would be used, if using an NSpire, the TNS file would be used.

You may want to make copies of the worksheet if using the TI-84.

Have students work in groups of 4 to complete the activity.

As a follow-up on another day or on the same day if block schedule, students can graph their plots on the same large sheet of poster paper, each student in the group using a different color marker. This way they can see where the similarities and differences are among the four cities.