During the St. Patrick's Day parade in Chicago, the local plumbers union dyes the Chicago River emerald green.
Students learn what PPM (parts per million) means and attempt to figure out how much dye is used to sufficiently color the river. Proportions ... ratios ... fun. dyeing-chicago-river-green.pdf
For members we have editable Word docs and solutions.
CCSS: 5.MD, 6.RP, 6.G, 7.RP, 7.G