It might not seem like scraping the top of a cold stick of butter with a knife could be a scientific test, but Professors Franz Ulm and Pedro Reis and graduate student Ange-Therese Akono say the process is very similar to the “scratch test,” which is perhaps the oldest known way to assess a material’s hardness and strength. Using butter as a launching point, they found that the scratch test is actually measuring a material’s toughness rather than its strength. Read a news release.