7th Grade Science

By Phelana

Seventh grade has been busy exploring multiple environmental issues, including climate change, ocean acidification, the effects of dams on ecosystems, and hypoxia (low dissolved oxygen levels).

Most recently, students learned how to use the Winkler Titration method to determine the levels of dissolved oxygen in samples of water. Using chemicals to “lock” the oxygen in water through a series of reactions, students then measured the amount of oxygen in their sample by adding a different chemical (sodium thiosulfate) to react with all the “locked” oxygen. They determined which sample contained the most salt by comparing the different levels of dissolved oxygen in three water samples. Students also compared their group’s data with that of the whole class, discussing consistency, sources of error, and validity of data. They will use Google Sheets to calculate averages and produce graphs to compare their results, presenting all this information in a formal lab report.

Here are pictures of students as they worked to carefully obtain data about their water samples!