Scientific Pet Peeve #1: Mass vs. Weight

Everyone has their pet peeves; unsurprisingly, at least a few of mine are science related.

Most people wouldn’t give a second thought to hearing someone say that something “weighs” twenty kilograms. I physically shudder whenever I hear or read such phrasing- and when I was a textbook editor, said shuddering was usually channeled straight into my red pen. Some of the first things you learn or teach in an intro physics class are the facts that mass is measured in kilograms, weight is measured in Newtons (or pounds), and mass and weight are not the same thing.

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Rain, Rain, Go Away…

…no, seriously, just stop already.

The particular suburb I live in happens to be a suburb of Seattle. It probably doesn’t rain here as much as you think it does, but it still rains a lot. In fact, it’s raining right now and it’s supposed to rain all week.

Which brings me to the water cycle.

Anyone who has ever taught science or worked on science textbooks- myself included- has probably had his/her fill of the water cycle. You’ve probably seen the basic diagram yourself. (My current favorite rendition is from the US Geological Survey.) Water evaporates from oceans and lakes, condenses into clouds, rains/snows back down to Earth, eventually ends up back in those bodies of water, and the whole process starts over again. Plants also contribute to the water cycle by absorbing groundwater and releasing water into the air- you can see this process on a small scale by building a terrarium.

The water cycle is an excellent example of how incredibly easy it is to interrupt a natural process. Suppose I went outside and collected about an ounce of rainwater. I could put that rainwater in an airtight jar and stick it in the back of my fridge, effectively removing a whole lot of water molecules from the water cycle. (A figurative gold star to anyone who can tell me how many! A literal gold star to anyone who can both tell me how many and meet up with me in person.) Those molecules had moved through the water cycle for billions of years, and with one action I can relegate them to a spot between the Sriracha and the salad dressing.

Of course, this wouldn’t do a thing about how much rain Seattle gets this week.