Prevalence of AI-generated language in introductory physics lab reports, before and after ChatGPT

This article investigates 797 introductory college and university physics lab reports to find the prevalence and character of AI-generated language in them since the release of ChatGPT. The lab reports were inspected manually and using two AI detection services, GPTZero and Turnitin. In the year since the release of ChatGPT, both AI detection services detect a statistically significant increase in generative AI language, which was found in 7.7% of lab reports. Students who used generative AI tended to use it multiple times. Six qualitative features of generative AI language were identified and given labels; verbose generality, fake concern, absence of numbers, suspicious formatting, significant 'waffling', and unrelated example. The AI detection services were found to be useful in detecting AI-generated language as they can highlight suspected sentences. Their AI detection scores generally correlated with the presence of manually found generative AI language. Care must be taken to identify false positives, primarily due to the technical writing nature of physics lab reports and AI-based spelling and grammar tools.