This screencast prompted a lot of student discussion on our Facebook page. The first issue was that I lack enthusiasm during the recording, making hard for students to stay motivated for the duration of the presentation. This is something I really need to consider for future screencasts. The second was related to two points I made during the video. One physics student (who is doing scholarship physics this year) stated that I had misinterpreted two common principles during the video. This was great and started a long online discussion with several students. I didn’t really expect that they would be confident enough to bring things like this up, but I am glad they did and were comfortable challenging the teacher! After asking him to identify the mistakes with supporting evidence, we carried on the discussion in our next theory class, deciding that I could have been clearer about one aspect I mentioned. A great result in the end though!