This post is by Kellie Taylor, Ed.D., the 2018-2019 Library of Congress Albert Einstein Distinguished Educator Fellow and was originally posted on the Teaching with the Library of Congress blog.
How does science affect our daily lives? Or as students might ask, “Why do I have to learn this?” In addition to making communications faster and some work easier, advances in technology can make our food products safer and last longer. Elementary students frequently learn about states of matter and may even build solar ovens or insulation boxes for experiments. While creating insulation boxes might seem to be a relatively simple science experiment today, methods such as these were once essential to providing safe food storage.
Start by showing your class the image After the ride and asking what they observe. After initial observations, focus students’ attention on the furniture the person is leaning on and invite them to speculate on what it might be. Facilitate a discussion that allows students to identify and state their claims and the evidence that supports them. Will they notice what appears to be a slice of cake on the top and second shelves – wonder what is in the bowl on the bottom shelf? What features of the object itself do they notice or wonder about?
Introduce the image of Mrs. Thomas without the caption. What do students see? Show the images side by side and invite students to compare them. Tell them that the objects served the same purpose, about 50 years apart. Allow time for students to update their hypotheses about what the objects are, citing evidence from the images.
Ask students how the two iceboxes work. How do they keep the food cold? Compare them to modern day refrigerators. Guide discussions to develop understanding that iceboxes date back to the 1800s and were the precursor to refrigerators and provided not only a decorative piece of furniture, but safe storage for food. Iceboxes typically had hollow walls lined with tin or zinc. Various insulating materials were packed within the walls such as cork, sawdust, and straw. A large block of ice in a top chamber created a cooler environment for food storage. Direct students to observe the photos to identify these and other features, such as the compartment above the food shelves, that might provide clues about how the object worked.
Challenge students to design their own iceboxes or insulation boxes. Their goal can be to keep their ice from melting. Since blocks of ice had to be purchased and delivered, poorly insulated iceboxes could cost the owner more money and could impair food preservation. Students can bring in recyclables from home to create their iceboxes. Provide possible insulation materials for students to choose from. Good insulation will deter heat transfer from the outside allowing the ice to stay in a solid state for longer. Establish a method for checking the state of the ice in the icebox and collect classroom data. Ice can be placed in plastic bags and weighed before being used in the ice box. The same bags can be weighed once the ice has turned to liquid. Ask students to predict if the weight will be the same.
Let us know what your students discover!