Astronomy clicker question: speed of electromagnetic radiation

Astronomy 210, Fall Semester 2008
Cuesta College, San Luis Obispo, CA

Students were asked the following clicker question (Classroom Performance System, einstruction.com) at the end of their learning cycle, during a review session before a midterm:

Which type of electromagnetic radiation wave travels with the slowest speed?
(A) Gamma rays.
(B) X rays.
(C) Microwaves.
(D) TV.
(E) (All travel at same speed.)
(F) (I'm lost, and don't know how to answer this.)

Section 70160
(A) : 3 students
(B) : 5 students
(C) : 7 students
(D) : 8 students
(E) : 7 students

This question was asked again after displaying the tallied results with the lack of consensus, with the following results.

Section 70160
(A) : 3 students
(B) : 1 student
(C) : 0 students
(D) : 23 students
(E) : 3 students

Correct answer: (E)

All forms of electromagnetic radiation travel with the same speed!

Pre- to post- peer-interaction gains:
pre-interaction correct = 23%
post-interaction correct = 10%
Hake (normalized) gain = -17%