Ask & Experiment

Ask & Experiment has experiments for you to try at home, activity books to download, PhysicsQuest resources for your school or after school group, and a way you can get your physics questions answered by real physicists.


PhysicsQuest, a free competition for 6-9th grade students and after school groups, consisting of four science experiments that give students clues to solve a mystery. Classes can submit their answers online and be entered in a random drawing for prizes. PhysicsQuest kits are free to registered classrooms and groups. 

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Fluorescent Olive Oil

Discover fluorescence with a laser pointer and a few drops of olive oil

Tea Bag Rockets

Fiery Tea Bag Rockets

What's the best way to turn a tea bag into a flying "rocket"? Set it on fire.

The Photoelectric Effect

How does one measure the kinetic energy of the ejected electrons resulting from the photoelectric effect?

My understanding is that the KE of the ejected electrons was dependent on the frequency of the incident light, not the intensity. A higher intensity light, however, would [have] ejected MORE electrons; provided that the light's frequency is high enough to overcome the work function of the metal.

Thus, it seems to me that an ammeter would show a higher current either way. A higher frequency light would produce faster electrons and a higher intensity light would produce more electrons. Given that current is a rate of charge (I = dq/dt), how did Einstein know that the frequency was the primary factor for the KE and not the intensity?

Find out the answer »

Activity Books


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