January 14, 2014

Investigating How to Make Icy Roads Safer

If you've ever driven on icy roads, you'll know just how treacherous they can be. How do road crews make the roads safer for travel? You may have seen them spraying a solution on the roads prior to a big storm, but what exactly is in that mixture and how does it help? With the extremely cold weather conditions across the country recently, this would be a timely topic for your students to explore.

I grew up in New Hampshire, and I can remember wondering why crews spread salt and sand on the roads. If you live in a cold climate where roads are often covered with ice in the winter, your students may have wondered the same thing. As it turns out, the salt lowered the freezing point of water which kept it from freezing at 32 degrees Fahrenheit, and the sand made the roads less slippery providing traction for the vehicles.

The Icy Road Investigation is a terrific way to have your students explore these concepts. This hands-on science experiment involves placing ice cubes in zippered plastic bags with sand and salt so students can observe the effects of those two substances on the melting ice. The activity uses simple materials that you can easily find around the home, and it's great for cooperative learning teams or students working with a partner. This lesson includes includes teacher directions and a 3-page lab report for students to complete as they conduct the investigation.

The Icy Road Investigation can be purchased alone, but it's also one of the seasonal lessons in my January Activities pack. In addition to this science activity, the 28-page January packet has over a dozen printables for January or winter including literacy, math, and social studies activities. Most of the lessons and printables are designed for cooperative learning teams or students working in pairs, but many of them can be used for independent work, too.



Icy Road Investigation Follow-up Activities   

Researching and Investigating Other Ways to Make Icy Roads Safer
Recently scientists have been exploring other options that are not only environmentally safe - they actually save money. A few days ago I read an article with information about various solutions that seem to work even better than salt water. Would you be believe some states are using substances like cheese brine and a solution made from beets?

I wonder what other solutions might work to make roads safer in winter? A fun follow up to the Icy Roads Investigation above would be to have students repeat the Icy Road Investigation using a different solution to see how the new substance affects the results.

Know-Wonder-Learned Chart Freebie
You could also use a KWL chart to guide students through the process of researching how to make icy roads safer. Give each student a copy of the free printable shown here, and display a copy for the class. Together, write what you know from your investigation in the Know column. Then ask students to complete the Wonder column by brainstorming questions they have about how roads can be made safer. Provide time for them to research the topic, take notes, and complete the Learned column. Wrap up the lesson by having students share what they learned with the class.

Critique a Winter Weather Report
Another engaging follow up activity is to have your students watch a video clip of a news reporter explaining why salt and sand are spread on highways and to discuss whether or not the information is scientifically correct. This idea was inspired by Debra Isabel, a 6th grade teacher from Pawtucket,  Rhode Island. Debra shared the link to a Youtube video with me in her TpT review of the Icy Road Investigation activity, and I loved the idea of incorporating an actual TV news video clip into the lesson! The news report is titled Good Question: Why do Plows Sometimes Drop Sand not Salt? and the video clip shows a reporter from KUTV2News in Utah explaining why salt and sand are dropped on roads during a winter storm. However, the explanation for why salt is used is not scientifically correct. Watch the video clip yourself to see if you can catch his error.


Did you find the inaccurate statement? The reporter said that the purpose of the salt is to warm up the road, but if your students have completed the investigation, they will know that salt doesn't actually make the road warmer. Salt simply lowers the freezing point of water to prevent ice from forming on roads at 32 degrees. Will your students catch this error? A written transcript of the news report is provided under the video which is helpful for analyzing what the reporter said and discussing why his explanation is not accurate.

Even if you don't live where winter weather is a problem, your students have seen enough movies to know that snow and ice on the roads create dangerous driving conditions. Exploring how roads can be made safer is a timely science topic, and your student are sure to enjoy this hands-on activity and research project.


1 comment:

  1. We just 11 inches of fresh powder last night mixed with freezing rain. Without a doubt, a smorgasbord of powder!

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