This "co-lab" uses data from other scientists. The data is represented by a colorful bulls-eye on each element's frame. By clicking on the center of the bulls-eye, you record two values. For example, you might be recording the atomic mass (on the x-axis) and the density (on the y-axis).

The elements are shown in the order of the independent variable (atomic mass in the example above). Your job is to locate missing elements. You'll be recreating what Dmitri Mendeleev, the creator of the periodic table, did.
You'll use data on atomic mass, density, melting point, and other properties to find patterns. When you locate a missing element, you should predict its properties.

Note that the numbers you'll be working with have only about two digits of precision. You're own care in collecting the data will also affect precision. Also, note that noble gases are not included in the elements for this lab.