This is one of my favorite lessons.
Lesson 1
The story “La inmolación por la belleza” is great to teach kids about the definitions of beauty. 
First we read the story. I use Jamboard so I can teach them how to do annotations. You can see the reading strategy on the first slide. After we read, students draw a study board as reading comprehension. Then, we do a cause and effect table.
Lesson 2
I show my students a video about the golden ratio. The video explains how mathematics may affect the way we perceive beauty, and how artists use it in their work.
As an example, I show them “Las meninas”. We analyze how Diego Velazquez used the golden ratio in his painting.
Using Dali’s “La persistencia de la memoria”, we try to find whether Dali used the same technique.
As independent work, students apply their knowledge of the golden ratio, as they analyze different paintings.