We're Sarah and Mande and we heard about a special metal that can kill bacteria: silver. Turns out silver has been used throughout history from Egyptians to American settlers to prevent bacteria in food and wounds. We stopped by the Sciencenter in Ithaca to learn more about how nanosized silver is being used today. Nanosilver is just silver broken down into such small pieces so it is even smaller than bacteria. We learned that there are some socks with nanosilver in them to keep them stink-free. But some people are worried that when you wash them, the nanosilver could leak out and harm good bacteria in the environment. Our question: Does any nanosilver leak out of socks when they are washed?
What did we do?
We bought a regular pair of socks and two different brands of nanosilver socks to test. After our own "smell test" we washed the socks. Then we took everything to a lab at Cornell University where Hekia helped us test how well the socks and the wash water killed bacteria.
What did we find out?
At the lab, we discovered that both pairs of nanosilver socks could kill bacteria, while the regular socks could not. Now for our wash water tests! The wash water from the regular socks and one pair of nanosocks did not kill any bacteria, but the wash water from the second pair of nanosilver socks did kill the bacteria! Could this mean that nanosilver was leaking out into the wash water and killing bacteria? Hekia told us that we would need to do a few more tests to be sure, but scientists are working on ways to keep nanosilver inside the products we buy to keep the environment safe.
- How do small things like nanoparticles get from here to there? Give this a try. Place 15 drops of vanilla extract inside a deflated balloon. (Make sure the outside of the balloon is dry.) Inflate the balloon and tie it shut. Grab a box and smell the air inside. Now, place the balloon inside and close it shut. Wait 1 hour. Open the box and smell the air. Did any of the small molecules of vanilla escape the balloon?
- Take 2 balloons. Fill one with helium and the other with air. Leave them in the same place and observe how long it takes each to deflate. Which one deflates faster? What can you say about the size of helium compared to the size of the different molecules in air (nitrogen, oxygen, carbon dioxide, etc.)?
- Molecules are always moving (even though you can't always see it). Try this! Grab a clear glass filled with water and put it in a place where it won't be disturbed. Add a couple of drops of food coloring. Observe the glass over a few hours. Can you make molecules move faster or slower? Try changing the temperature of the water?