Vibrations, Waves & Sound

These Next-Time Questions are for you!

Next-Time Questions are favorite insightful questions I have asked my students over my teaching career. I have embellished them with cartoons to catch interest. Their intention is to elicit student thinking. My use of them was posting several in a glass case outside my lecture hall—without answers. The wait-time for answers was one week. I could have called them Next-Week Questions, which would have been more appropriate.

Most of these have been published over the years as Figuring Physics in The Physics Teacher magazine. They have also been in ancillaries to my Conceptual Physics textbooks, and physical science textbooks as well. My hope is that teachers will pose the questions, and withhold answers to “next time,” which could be as early as the next class meeting. Their educational value is the long wait time!

Although these are copyrighted, teachers are free to download any or all of them for sharing with their students. But please, DO NOT show the answers to these in the same class period where the question is posed!!! Do not use these as quickie quizzes with short wait times in your lecture. Taking this easy and careless route misses your opportunity for increased student learning to occur. In my experience students have benefited by the discussions, and sometimes arguments, about answers to many of these questions. When they’d ask for early “official” answers, I’d tell them to confer with friends. When friends weren’t helpful, I’d suggest they seek new friends! It is in such discussions that learning takes place.

You may wish to project these Next-Time Questions rather than post them. One or two projected at the end of a class session is fine. The answer is given “next time” the class meets—or at some interval where wait time is at least a day.

These Next-Time Questions are the outcome of my long and wonderful teaching career. They’re yours at the click of a mouse. Please use them as I suggest.

~ Paul Hewitt


Science - Linear Motion


Newton's 1st & 2nd Laws

Thermodynamics & Thermal Expansion

Newton's 3rd Law

Change of Phase



Light Properties


Reflection of Light

Rotational Motion

Refraction of Light



Projectiles & Satellite Motion

Electric Current

Atoms & Solids



Nuclear Physics


Special & General Relativity

Exponential Growth

Supplementary Resources for Conceptual Physics from Paul Hewitt