Many of these students aren't sure where they want to go in life, or how to get there. So in addition to the activity, we want you to talk about YOU! How did you get into this line of work, or into math/science in the first place? What other jobs have you had? What do you like - and dislike - about your job? What else do you do - hobbies, family, etc.
Remind the students to take plenty of math and science courses in high school, so that all of their options are open. Try to find links that go beyond traditional math/science areas. And of course, leave plenty of time for questions!