This study examines the effects of holograms when used for online learning. The research question is: "How does a holographic teacher projection affect engagement of the students with the learning material?". The engagement of students was compared in different lectures. The base lecture was a zoom lecture. The holographic lectures were a VR lecture, a HoloDisplay lecture and a robot lecture. A big experiment was done where different people attended one of those 4 lectures. After the participants were done watching the lectures they had to fill in questionnaires. The data of these questionnaires was then used to compare the lectures. The main conclusions are that Zoom lectures definitely take more attention than holographic lectures. Another conclusion was that the HoloDisplay and the Robot lecture are more engaging than a normal zoom lecture, this conclusion was backed up with statistical tests. There was no evidence that either the HoloDisplay or the Robot lecture was more engaging than the other one. Both of them need to be looked into further and be developed further. These ways of teaching can definitely be the future of online learning.