The Pencil Eye Trick

This pencil eye trick is one cool thing to try. It is a nice "hook" to use when introducing the human eye unit to your students. It is a simple thing to do that will take a few minutes at most. Each student will need two sharpened pencils.

The Eye Trick:

1.Close the right eye and keep it closed.

2.Grab two sharpened pencils and hold one in each hand with the pointy end facing each other.

3.Hold the pencils far apart from each other, one in each hand, as you extend your arms.

4.Keep the pencils in front of you, as you move each one far off to each side. Stop when your

arms are both fully extended.

4.Now, keeping the right eye closed, slowly move the two pencils in together to try and

make the pointy ends touch each other.

5.Try it a few more times until you get the points to touch each other.

6. Repeat the steps with the left eye closed and see how it goes.

7.After you have tried this trick with both eyes, now get the two points to touch with both eyes

opened.

What happened? What is the science behind this? Why was it harder to make the points meet when your eyes were closed? The pencil-eye trick is no trick when both eyes are open because each eye sees at a different angle. Your brain merges these slightly different angles from both eyes to create depth/distance perception. This makes it very easy to bring the pencil tips together with both eyes open. Take one eye away, and you are only seeing the objects from one angle. This causes your view to be off, and so will your depth perception.

The 20/20/20 Eye Rule

Did you know that screen time with little to no breaks can be hard on your eyes? This is because you tend to blink less when your eyes are looking at a digital screen for a prolonged period of time. This causes your focusing eye muscles to remain in a state of contraction, and you blink less often. This eye strain can cause headaches, and the blinking less can make eyes more dry, which can cause your vision to be blurred. One of the roles of blinking is to help naturally moisturize the eyes, helping make vision clearer, so blinking is good for eyes. Less blinking, not good for the eyes. Eye strain from digital screen time can happen to a teen playing a video game that lasts for hours, to a student spending hours on homework assignments, or to you while doing your own routine computer work.

The good thing is that the headaches and blurred vision from too much screen use are almost always temporary. They can be resolved by taking simple breaks. Here is a simple tip you can apply to your life and teach your students about to. It is the 20/20/20 rule that most eye doctors recommend. This rule basically says for every 20 minutes of screen time use, look away at an object that is 20 feet away for 20 seconds. Shifting your focus to a distant object for 20 seconds relaxes the focusing eye muscles, reminding you to blink more often which can re-lubricate the surface of the eyes.

Too much screen time can lead to more than just headaches and blurry vision. It can also cause poor sleep quality (especially if it is done right before bedtime), neck and upper back pain, and weight gain from sitting too much. While we need our devices for many important daily uses, it is important to take small breaks throughout your day to help you feel better and make a healthier you. Get up and go for a walk, go for a swim, play a musical instrument, talk on the phone with a friend, get in the kitchen and make a new recipe, get out and garden. Do whatever you like in your rest/breaks, even if it means cleaning the house, like the dishes that are in your sink waiting to be washed, or the pile of laundry that has been on the couch for two days. Lots of rest/break opportunities await. Ask your students to share what they would like to do during their digital screen breaks. You will likely hear many different answers.