It’s Day 83 and the first day back from break! We kicked off Unit 7 (counting particles too small to see) today with a challenge!
I presented my students with this large bag of packing peanuts and asked them to figure out how many peanuts are in the bag. I provided them with a small sample of peanuts (about 20) and a balance and set them loose.
Most groups massed a couple peanuts and the bag of peanuts, did some math and called it a day. There are always a few groups who really analyze all of the variables. These groups make sure to mass their whole peanut sample and even account for the weight of the bag in their calculations.
Besides being a good introduction to counting by weighing, this activity brings back many basic scientific skills like measurement and error analysis. I had each group present their methodology for their classmates to critique. We also discussed why volume is not very useful for this activity and in what instances you might want to count by weighing (SPOILER: like counting atoms!).