Don't Freeze My Feet

The high concentration of oleic acid in reindeer feet, which has a lower melting point than other fatty acids in their legs, prevents the tissue from solidifying in cold temperatures.

In this performance task students will analyze data to determine how molecular structure affects melting point. They will do this with the intention of figuring out why reindeer feet are able to withstand cold temperatures. In segment 1, students will learn that reindeer feet have a high concentration of oleic acid in their feet as compared to the rest of their legs. After we ask why this is true, we look at the melting points of oleic acid as compared to the melting points of other fatty acids present in reindeer legs. Students use this data to make the connection that, because oleic acid has a low melting point, it is less likely to freeze in cold temperatures, which allows reindeer to retain their mobility. In segment 2, students ask “What is special about oleic acid that allows it to have a lower melting point as compared to stearic acid and palmitic acid?” To answer this question, students will look at a new data set using CODAP that will allow them to compare the number of double bonds in a molecule and the melting point of a molecule. Using this data, students should come to the conclusion that, as the number of double bonds in a molecule increases, the molecule’s melting point decreases. In segment 3 students will summarize their findings in a scientific poster and be given the opportunity to both receive feedback and give constructive criticism in a controlled environment. After this, they will be able to revise their work and reflect on why scientists organize data in the ways that we do.