The idea behind learning from animations is that some topics are hard to teach through text or static pictures. These include processes showing movement, dynamics, procedures or steps in solving a problem. When learning from animations, students watch short animated movies showing dynamic processes, such as how the heart beats or how to solve a maths problem. Compared to looking at static images in a textbook, animations can be better at revealing movement and speed. They can show how an expert tackles a difficult problem through a worked example. To be successful, animations should highlight the relevant parts and zoom into the most important movement. Compared to static images, animations show movement and speed directly, without a need for arrows to indicate the direction or rate of flow. Research has led to a set of animation design principles for successful learning.