Science Snippets

Dear Teachers
In these Science Snippets, I provide short videos and write-ups on activities that are effective, easy to do and that won't take too much time to prepare.
Education, in essence, is about the sharing of our experiences and knowledge.
It gives me great pleasure!
Carl Ahlers
Scientist & Educator

Physics

Light: Persistence of Vision

There are numerous oscillating objects, electromagnetic waves and flickering lights out there that cannot be observed by human sight. Our sense of sight is just not able to perceive and detect these fast changing images. In this snippet I will show you an easy way to expose this “secret world” to your students using a solar panel and speaker.  Watch the 3 minute video or download the PDF file below for a number of activities on making flickering light audible, hearing AC and DC and Persistence of Vision.

Light: Photoluminescence

Photoluminescence is the production of light without any heat, using high energy photons.  As photons are light particles, this means we can produce light by stimulating a compound with light particles!  This happens when photons bump electrons to higher energy orbital levels.  Energy is then released in the form of light when the excited electrons return to their ground states. Watch the 2 minute video below for two demonstrations on photoluminescence that will truely engage  
or read and download the 3 page PDF file below.

Chemistry

More to follow . . .