Surface Tension Demonstrations


tamiWe Water Molecules Stick Together! | Surface Tension Demonstrations

by: Tami O’Connor

I am a believer that observing discrepant events burns concepts into students’ memories far longer than simply reading the facts of the lesson from a text book.  A few years ago I was designing a unit on surface tension.  Because so many awesome hands-on activities deal with this topic, my greatest problem was picking and choosing!  In this blog, I will describe one of my students’ favorite surface tension demonstrations.  It teaches about surface tension and capillary action.

surface tension demonstrationsMaterials (per student):

  • 2 – plastic cups (I prefer Solo brand)
  • Electrical tape
  • 18 inches of white yarn
  • Food coloring
  • Water

Procedure:

DSC_0278Cut 2 pieces of electrical tape (1 inch each).  Using the tape, affix the end of the yarn to the inside bottom of one of the cups.  With the other end of the yarn, repeat with the second cup.  Put as much yarn as will fit into one of the cups, and add water until the cup is about half full.  Holding the cups close together, pour the water from one cup to the other allowing the yarn to flow with the water.  When the yarn is thoroughly saturated you are ready to begin. Read the rest of this entry »


Picture This!


MARTY SAGENDORFPhotographing Science

by: Martin Sagendorf

It’s Easy:

To take neat photos of little things.

We Think:

That our digital cameras, web, and cell phone cameras can only take ‘life-size’ photos… but…

We’re Lucky:

These cameras can also photograph images provided by other optical devices…

Such As:

Microscopes and spectrographs.

Because:

These devices provide collimated images (i.e. focused at infinity) and an ordinary digital camera device can photograph these images.

The Images:

Are much smaller than ‘full frame’ – a photo-handling program is an absolute necessity – to enlarge and enhance the images.  For the camera images shown, the camera used is a Panasonic DMC-TZ4.

Read the rest of this entry »