Optical illusions are a great way to explore some science behind how our eyes and brains work. Kids will love working with these because they are exciting and full of surprises! This makes a great science activity for learning.
First, get into the science!
Before exploring different types of optical illusions, spend a bit of time with your kids getting into the science behind them. According to insidescience.org, the brain takes shortcuts when light is being reflected in the eye, so that you can focus on the important images in front of you. These shortcuts are what cause our brains to be fooled by optical illusions, if they take advantage of perception, light, and movement in the right way. Beau Lotto also explains how these illusions take advantage of colour in his TED Talk (time: 2:29). The different ways our eyes perceive the colour of objects, their illumination, and their spaces, will all affect what image we see.
Then, apply the science to the illusions!
In Beau Lotto’s TED Talk, he points out that the same image can be viewed by a group of people in very different ways. This presents an experiment that can be lots of fun with kids of all ages, since everyone might see an optical illusion differently. In order to explore this scientific phenomenon with your kids, present them with several optical illusions. As you go through these illusions, have your kids try to figure out what is going on in each image, and why the brain is being tricked or confused by it. Take a poll to see what the majority thought the image was, and what scientific phenomenon they thought was occurring.
To get you started with optical illusions to show, here are two sites with lots to choose from:
The following are some examples of the types of explanations you and your students can come up with for different kinds of illusions:
- Spinning illusions cause blindness.
- Optical illusions can trick our brains into seeing motion, despite being stationary image like this image: https://www.insidescience.org/sites/default/files/OI_5.png.
- Other illusions, however, are actually moving and use their movement to trick your brain into blocking out part of an image. This causes you to experience a touch of blindness. Check out this website to test out a motion illusion for yourself!
- Some illusions trick our brains into seeing things that don’t exist.
- Some optical illusions mislead our brains to perceive an image as having a component that is not even there. These are the illusions you may see that appear to have more than one possibility of a pathway, height, or number of objects. One popular example of this is an elephant drawing that appears to have extra legs. You can view it here: http://www.optics4kids.org/home/content/illusions/elephant-legs/
Take it a step further by creating your own illusions for a science activity
Once you have thoroughly explored optical illusions and how they work, encourage your students to create their own. Or, have them create a copy of an existing optical illusion. Go around the class and have fun tricking each other!