Measuring a changing quantity in our temporarily locked down

The project is to measure a changing quantity in our temporarily locked down, unchanging world. Try to choose some thing (or, for brownie points, multiple

things!) that change enough to collect a couple dozen data points (in particular, (x,y) pairs) over a couple of days (or minutes/hours - you get it) of data

collection.

Be creative!

Calculate the approximate rate of change and concavity/convexity of your data series and discuss:

What qualitative statements can you make about the behavior of the quantity during the observation period?
From the point of view of someone who would like to either understand a phenomenon better, or exercise control of the quantity towards a desired outcome: what

model, additional measurement, material property, etc. do you think you might consider in order to formulate predictions about this quantity?