My playground book shows physics in dance. I describe balance and rotation movement in dance. To illustrate problems I use my drawings. In the first place, I put explanations of the problem, the physics model to present a problem.

So after balance explanation, I put lever with two weights. The user can change the position and mass of it and then run code to check if a balance is kept. To present it I use SpriteKit. So I can use many needed SKActions.

The second problem is about the rotation. I’m modeling problem using rotating Xmas tree. I choose this image because it is funny and will fall into students memory because of that. This problem has a 3D representation. To do this, I use ARKIt and SceneKit. If the user loses a node, that sometimes happens in Augmented Reality, he/she can tap, and the node will appear just in front of him/her. To implement that I use the current position of a device and its orientation. On the Xmas tree, there are nine bubbles; each of them represents mass. Movement of bubbles changes the moment of inertia of the whole tree because of that and conservation of angular momentum rotational speed changes. To change the position of a bubble you can use sliders. Sliders are positioned in a particular way to present orthographic projection of each level of the mass tree. All nodes are created in Swift itself.

I choose this topic because I’m a physicist and I love to dance. And physics is everywhere. So I’ll hope some people will be able to learn some intuitions from my playground in pleasure and funny way.