Residents of colder climes are familiar with salt trucks that scatter their loads over the road after (or during) a heavy snowfall. Rock salt was historically a relatively cheap and widely available resource. Recent years have demonstrated that demand can exceed supply. Environmental concerns about how much salt runoff is harmful to the environment, or even to domestic landscaping, has sparked interest in the over-usage of salt on icy roads. What better idea then, than to find alternative de-icing chemicals? Many companies have already released alternative products, and research is ongoing. You can be a part of that as well.
PURPOSE
Identify common chemicals that will help melt ice. As a secondary purpose, you may want to compare how well each chemical performs.
MATERIALS
Before you go any further, make sure that you have a cold environment available. If it is winter and below freezing, you can use your sidewalk or driveway. Otherwise, you’ll need access to a controlled temperature freezer, ideally one that you can adjust.
You’ll want water, of course, and a way to apply it evenly to surfaces. A spray bottle with a squeeze trigger might work well, but feel free to be creative.
Your experiment should be conducted on uniformly flat surfaces. These might be sidewalk squares, sections of driveway, kitchen plates, metal squares, or any other surface that suits your needs. The sidewalk would be ideal, as it is relatively level, and provides a real-world scenario. Because it is a public area, however, make certain that you put up warning signs to keep people from either hurting themselves or from ruining your experiment.
A thermometer will allow you to measure the temperature at which each experiment occurs. This is a very important piece of data, so make sure it’s accurate. A thermometer that measures the temperature of the surface (or ground) will be more helpful than a thermometer that measures the air.
A clock or timer will allow you to measure the time required to melt ice, should you wish to capture this information. This is optional, and depends partly on how dedicated you are to watching ice melt. Don’t worry, you can just check periodically.
Finally, you need the common chemicals that you will test for their ice-melting proficiency. You should probably include salt, since it provides a well-known reference point. Beyond that, the sky is the limit. You can browse chemicals in the house (but read warning labels – anything bad for you is probably bad for the environment as well), check out alternative commercial de-icers, or try your great-aunt’s secret ice-melting formula.
EXPERIMENT
You can test your anti-ice chemicals in two different ways:
1. How well do they melt ice?
2. How well do they prevent ice from forming?
Experiment #1
In the first experiment, you’ll want to start with evenly iced surfaces, spread a known amount of chemical over the ice, and see whether the ice melts. Be sure to measure the temperature and record melting time as best you can.
You have several variables to experiment with. Performing the experiment at different temperatures will let you determine the temperature range for which a chemical is useful as a de-icer. Changing the amount of chemical used gives you an idea of how potent it is as a de-icer. Varying the thickness of the ice accomplishes the same task. Make sure to only change one variable at a time, or your data won’t be meaningful.
Experiment #2
The second experiment is almost the reverse of the first. Spread a known amount of the chemical over the dry surface, and then apply a controlled amount of water. Monitor the temperature, and observe whether ice forms or not. (If it does, you can time how long it takes to form.)
Again, you can repeat the experiment using different temperatures, different amounts of chemical, or different amounts of water. Remember not to change more than one variable at a time.
For both experiments, remember to record all your data carefully. It might be helpful to create a table in advance, so all you have to do is record temperature, amount of chemical, amount of water/ice, time, and any observations you may have.
RESULTS
Once you’ve generated all your data, you can get along with the comparison. Evaluate not only which chemicals worked to melt the ice (or to prevent it from melting), but what temperatures they were effective at, how much was required to melt the ice, which ones worked at the coldest temperatures, which kept ice from forming the longest, etc.
CONCLUSION
Based on your results, you should be able to draw conclusions about which chemicals are potentially useful as a de-icer. Could any of them replace salt? Besides looking at how they performed, also be sure to check how easy it is to get the chemical. It has little value as a de-icer if it can’t be obtained in bulk quantities at reasonable prices. Cities can’t afford to spread chemicals that cost hundreds of dollars a pound (or kilogram) on their streets multiple times a year. Finally. if you find something that has promise as a de-icer, make sure to pass that information on.
