Tech Salad

With Crunchy Bits and Bytes

Macro Photography and Chemistry

Yesterday I had a bit of downtime while waiting for a video to render, and decided to try something I’d  read about. I used a coffee stirrer to place a drop of water on the lens of my iPhone. The first thing I shot, fearing damage to my device, was a bit of terry cloth. I made sure I had it handy just in case the water strayed off the lens. I had an iPod on my desk, and tried that next. This was easier to mange since the lens on the iPod is slightly recessed within its metal frame. The water held in place longer.

I thought about the process some more and realized the key to the drop holding its shape was related to the surface tension of the water. So, I went upstairs and talked to Mr. Kupferman, our Chemistry teacher. While he admitted fluid dynamics was not his area of expertise, he knew where to look this up. He suggested we increase the surface tension by adding salt, and the number we needed was a solution of just regular table salt in water, with a molarity of 6.

I know about molarity, but I don’t remember all I learned. Luckily, that was the exact topic Mr. Kupferman’s students were covering in class today. They figured out I needed ten milliliters of water and 3.5 grams of salt.

Perfect! The drops of salt water hold stable longer and I was able to take clearer pictures with higher magnification. Here are a few of them. Now I need to find a class where we can explore, say, insect wings, or particles of sand, or anything else that looks interesting up close.

taken with mineral water

Taken with tap water - eagle on a dollar bill.

Taken with salt water.

Taken with salt water.


Date imprint on a wheat penny.


My jeans ;-)

Note: Please remember that any damage resulting from exposing your iOS devices to water is not covered by any warranty.

One Comment

  1. Very cool! Great idea to increase the surface tension. Thank you for posting the amounts of water and salt.