The relative viscosity of 2,2,4-trimethylpentane can be measured using a stopwatch, and compared to other liquids.
The relative viscosity of 1-pentanol can be measured using a stopwatch, and compared to other liquids.
A piece of glass is scratched with a diamond-tipped stylus, showing that diamond is harder than glass.
A piece of tape pressed against a sample of molybdenum sulfide will peel off layers of the sample. Additional tape can be used to cleave the peeled sample hundreds of times.