What is something you learned from this article? (3-4 sentences)

When an element changes its state or position, the duration of the animation should be slow enough so that the user notices the change, but fast enough not to cause a wait. Numerous studies have found that the optimal speed for interface animation is between 200 and 500 milliseconds. On mobile devices, the Material Design Guidelines recommend limiting the duration of animations to 200-300 milliseconds. For tablets, the duration should be 30% longer — about 400–450 milliseconds, because the screen size is larger and therefore the object overcomes a longer path when changing position.

What was your favorite part of this article? (3-4 sentences)

Regardless of platform, the duration of the animation depends not only on the distance traveled, but also on the size of the object. Smaller elements or animations with smaller changes should move faster. Animations that move in straight lines look very unnatural and artificial to the human eye. All animation applications should use animation curves.

Copy and paste a quote you found compelling, interesting, or cool

"If the animation is built correctly, then it is unobtrusive and does not distract the users from their goals. If it does, you either need to soften it or even remove at all. That means that the animation shouldn’t slow down the user or prevent from performing the task."

On a scale from 1 to 10, how much did you enjoy reading this article? If you scored below a five, please briefly explain why.

I give 10. I think this article is very helpful for me to understand the main principles & rules of animation design .