Large language models, such as ChatGPT, have great potential to enhance learning and support teachers, but they must be used with care to tackle limitations and biases. This paper presents two easy-to-implement examples of how ChatGPT can be used in physics classrooms to foster critical thinking skills at the secondary school level. A pilot study (n=53) examining the implementation of these examples found that the intervention had a positive impact on students' perceptions of ChatGPT, with an increase in agreement with statements related to its benefits and incorporation into their daily lives.