Using phenomena for teaching the nervous system in your human body unit opens many opportunities for unique learning experiences. There are so many interesting experiments you can try in class with easy-to-find materials. Here is a list of eight different ideas for teaching the nervous system using experiments. Use these as anchor phenomena for your nervous system unit!

How can a flashing LED light explain color vision?

A small LED bulb with red, blue, and green lights inside looks purple when still, but when it moves you see the individual colors flashing separately. It makes a great anchor phenomenon: students explore how sensory receptors, the eye's structure, and the brain work together to build the image we see.

I use this as an anchor phenomenon for teaching the nervous system unit. The experiment involves a simple LED bulb with red, blue, and green lights inside. They flash so fast that they look purple when the bulb is still. However, when the bulb is moving you see the individual red, blue, and green lights flashing at different locations.

Here is an example of this item in action from an item sold by Teacher Source. I purchased the bulb and taped it to a meter stick with a battery compartment that can be turned on and off. This made it easy to move around while I demonstrated it as I walked around the class.

In my unit, students explore how we receive information through sensory receptors, the structure, of the eye, and model information transfer to the brain. If you’d like to try my MS-LS1-8 sensory receptors and nervous system unit, it is available in my TeachersPayTeachers store.

How does a reaction time test demonstrate the nervous system?

With just a ruler, one student drops it without warning while a partner catches it between their fingers. The distance the ruler falls converts directly into reaction time, so students collect precise data without a stopwatch. It's a simple, popular way to show the stimulus-response pathway in action.

Students love this experiment and it’s easy to perform in class. The only material you need is a ruler. Have one student hold out their hand sideways with their thumb on the side to grab the ruler as it falls. One student will hold the ruler (with the 0-inch reading facing down). Another student will hold out their hand sideways with the ruler between their fingers and thumb. The student holding the ruler will release it without letting the other student know when they will drop it.

I like this experiment because it easy to collect precise data. Students don’t need to operate a stopwatch to measure fractions of a second of time. They simply convert the inches that fell (where they stopped the ruler with their hand) into their reaction time. I’ve added a chart below to show the conversion.

How do you show a stimulus-response pair with pupil dilation?

This one needs no materials. Dim the lights for two or three minutes so pupils dilate, then have partners watch each other's eyes as you flip the lights back on. Students are amazed at how fast pupils contract, which sets up a clear discussion of cause and effect in the nervous system.

Your students will say, “Woah!” with this one. And best of all, it requires no materials! I turn off as many lights as I can safely in my classroom. You will need to wait about two or three minutes in low light for pupil dilation to occur. I pass the time by asking them to tell me about a time they left a movie theater and saw how bright the outside light appeared. I also ask them to explain a time they went somewhere extremely dark and how they were able to see better after about a minute.

Then, I have them pair up and look at their partner’s pupils. I count to three and turn on the lights. Students are always shocked by how quickly their pupils will contract from dilation. Then, I will repeat the experiment and tell them about the structure of their eye, focusing on the pupils. Flip the lights on again. Then, ask students to explain the cause and effect of pupil dilation.

How can a memory test teach the nervous system?

Build a slideshow with about 20 quick instructions and a list of five random numbers on the third slide. Move fast so students can't secretly write the numbers down, then ask them to recall the numbers at the end. It's a fun lead-in to why phone numbers are seven digits—about our working-memory limit.

This one is also fun and requires no materials for teaching the nervous system unit. Make a PowerPoint with about 20 instructions (count from 35 to 25, write the letters in your name in alphabetical order, name the states that share a border with your state, etc.). On the third slide, put a list of five random numbers between 1-50.

During class, have students put a piece of paper and pencil on their desks. Then, go through the PowerPoint fairly quickly to make sure they don’t have time to secretly write down the numbers. At the end of the 20 instructions, have students write down the five numbers. Then, see how many were able to remember them.

This is also a great way to discuss why we use certain sets of numbers in everyday life. For example, phone numbers are seven digits because that is about how many numbers we can remember at a time (although our phones do that job for us now)!

What does the Invisible Gorilla show about attention?

The Invisible Gorilla selective-attention test demonstrates how focused attention can cause us to miss obvious things—about half of viewers never notice the gorilla. Hide the video's title so students aren't tipped off, and use it to open a discussion about how the brain filters what we perceive.

This is an experiment that has been performed in numerous ways by researchers. I like to show this version by Christopher Chabris and Daniel Simons because of its simplicity. Be sure to hide the name of the video so students don’t get a hint about the purpose when they watch.

The researchers say that only about half of the participants will say that they saw a gorilla when asked. Over the years, I’ve found this to be accurate when using this in my classroom.

If you want to find other versions, look for “selective attention tests” on Google.

How does a color vision simulation explain how we see?

Before running the simulation, teach the structure of the eye: rods give us grayscale vision in low light, and three types of cones (red, green, blue) let us see color. Then pose the puzzle—if we only detect red, green, and blue, how do we see purple?—and let students build colors and trace the optic nerve to the brain.

This is a great simulation to show how our brains and eyes are able to use photoreceptors and light to give us vision. Before using this, we learn a bit about the structure of the eye. We have structures called rods and cones in the back of our eyes. Rods allow us to see in grey scale in low light. Cones (of which we have three – red, green, and blue) allow us to see color.

After learning this, I pose this question to my students: If we only have detectors for red, green, and blue, how do we see purple? Then, students create purple (and many other colors) using the simulation. It also shows a model of our optic nerve and brain. See if your students can explain why there is a nerve leaving our eye and connecting to the back of the brain!

How can a tin can telephone model the nervous system?

Most of the nervous system is invisible, so a tin can telephone gives students a concrete model: one can is the sensory receptor, the string is the nerves, and the second can is the brain. The key is pushing students past the model—naming what each part represents and how it differs from the real thing.

Most of the nervous system cannot be seen. This means that our students must think in abstract terms about nervous system structures. One way we can help our students do this is through modeling their functions. Try this model while teaching the nervous system this year!

An easy and fun way to show how the nervous system transmits information is to use a tin-can telephone. It’s easy to build. Take two cans (such as vegetable tin cans) and run a string between them. When you speak into it, the vibration from your voice will be transmitted in waves through the metal of the can. It will then travel through the string and into the metal of the second tin can. The vibrations of the tin can make a sound similar to your voice.

An important note about using modeling like this is that students need to think beyond the model. They should explain what each part of the model represents, how it is similar to the structure, and how it is different. Here is an example:

Why is it easier to see stars out of the corner of your eye?

Rods, which handle low-light grayscale vision, sit off to the side of the back of the eye rather than dead center. So looking slightly to the side of a faint star lands its light on more rods, making it easier to see. It's a surprising fact that ties eye structure directly to real experience.

This last one is a fact I didn’t learn until much later in my science career. If you look at a star directly, it is harder to see and will appear dimmer. The best way to view stars at night is by looking just slightly to the side of them.

The reason for this has to do with our eye’s structure with rods and their location. Rods are responsible for seeing in low light and give us our grey-scale night vision. They are not directly in the back of the eye but to the side of it (in a region called the macula). When we look at the side of an object, we can see dim light from it more clearly (but not the colors which is the responsibility of our cones). Since stars are so far away, the color is not as important.

Teaching the nervous system offers plenty of opportunities to incorporate interesting phenomena into our lessons. I find that these kinds of experiments and demonstrations really stick with students. They will sometimes tell me that those were their favorite thing we did in science class that year. Or, it will be something from my class years later. And, in my opinion, giving students the ability to wonder and be curious is one of the best skills we can teach them in middle school science.