This is a color illusion activity using the flags from 21 Spanish speaking countries.
It's a fun activity you can use when teaching colors to incorporate a little science and art into your lesson. Here is how it works:
When you stare at a color for about a minute and then stare at white, the image will appear as a ghost image in that color's opposite color on the color wheel.
For example, on the color wheel the opposite of yellow is purple, so if you stared at a picture of a yellow banana for a minute and then stared at a blank piece of white paper, a ghost image of the banana would reappear on the white paper, only in purple. For the Flags activity, students get a flag labeled to color in Spanish, with the opposite colors on the color wheel, without prior knowledge of what their flag should look like or what the opposite colors will reproduce. After they color it in and do the activity as in the directions, they should see their flag reappear as a ghost image in it's correct colors. You can have the whole class do the same flag or to make it interesting you can have each student do a different flag.
The second half of the power point is how the flags should look. You can print them and fold them in half to place on the desk tops or you can download my Free offering "Flags to Fold"
Also included is a sign for the colors and their opposites on the color wheel in Spanish.