Activity 4

Try the activity!

Each of the lake images on this page is a single thin line of radar data collected as a set of 'points' as the plane flies along an established flight line. The scale along the bottom is measured in kilometers (km). How does a *km compare to a mile?

SIZE UP! Click on each of the images to enlarge it and calculate the lake 'size' (remember to consider carefully what information you actually have).

Which image has the largest lake? Which has the smallest? (remember scale differences)

Which lake is the the furthest under the ice? Which lake is closest to the ice surface?

*Each km is 0.62 miles, approximately 2/3.

Measuring Lakes

Now that you know what a subglacial lake looks like in a radar image you can start to explore under the ice. Let's see if you can calculate how 'big' the lakes are. There are many ways to talk about the size of a lake...some common ones are its length, its area and its volume. To calculate each of these we will need certain types of information. First let's determine what information we would need to calculate each item below, and then let's consider if we have what we need. What do we need to figure out the lake's:

Length_________

Area___________

Volume__________

How do these lakes 'size up'?

Now let's see what information we have. For each image you have data from one air flight measuring one variable: depth along a single line, or crossing of the lake (click on the image to the left to enlarge). The 'X' axis of the image shows distance, or how far the plane has traveled along that line of the lake, and the 'Y' axis shows depth at the corresponding location. Using the data provided which of the calculations (length, area, volume) can you complete for the lakes?

Read through "Try the activity" and complete the excercises using the student worksheet below. Be careful! Note that not all the IMAGES use the same scale. Why would we chose different scales for the images?

Student Activity Worksheet download response sheet word pdf