Photos courtesy of Deer Park School District
Seventh graders in Natalie Sabia’s class at Deer Park’s Robert Frost Middle School recently learned about density as a property that can be used to identify a sample of matter, and explored how an object’s density plays a role in whether it sinks or floats in water. They then used their knowledge of density to create density towers using different liquids.
The students had already spent time in class analyzing a nine-layer density tower made with liquids and solids. Students were able to determine the densest liquids and solids based on their position in the tower; denser objects sink to the bottom, less dense objects rise to the top.
In this hands-on activity, students worked in collaborative lab groups to create their own density towers. Students were given six liquids – honey, mineral oil, syrup, water, rubbing alcohol and dish soap – as well as the density of each liquid. Students then had to use their knowledge of density to determine the order in which they should add the liquids to their test tube. Students had to know that the densest liquid should go in first, on the bottom, and the liquids should be added after that in order of descending density. Once Sabia approved their “plans,” students were given the go-ahead to start building their density tower, layer by layer.
“This activity challenges students to work in collaborative groups, analyze data and apply their scientific knowledge to create an end product that they can be proud of,” Sabia said. “The students were so excited to show me their completed density towers.”