Month: March 2018

Reaction Time – Testing Your Nervous System

In the course of our human body unit, we have just wrapped up the nervous system. Part of the discussions included how our brain can send and receive messages to other parts of the body through neurons. Sometimes, these messages are sent almost immediately, without us really thinking about the process (think about when you touch a hot stove!). Other times, our brains take a little longer to process what needs to be done.

To demonstrate this point, the class did a quick reaction time lab. I first found this lab at and I’m so glad I did! It was a blast!

For the lab, all you will need is a ruler or meter stick, and a conversion chart like this one:Image result for reaction time table If you don’t have a conversion chart ready, simply use the inch marks as your indicator!

You can get the entire lab and worksheets for free by visiting and signing up!

Round 1

  1. The student being tested holds their hand out, ready to catch the ruler.
  2. Another person in the group holds the ruler with the end of the ruler (the “zero” inch mark) right above the blindfolded person’s thumb
  3. The person holding the ruler will drop the ruler without warning, and the student being tested must grab the ruler as quickly as possible.
  4. Check what inch mark the top of the student’s thumb is resting on.
  5. Record the number, then use the conversion chart to see the reaction time (if using the conversion chart)
  6. Repeat this process two more times. Students then find the average of all three trials.

Students had a great time watching each other try to catch the ruler as quickly as possible!  

If your students seem ready for the next challenge, gather several blindfolds and have students test their reaction time in a slightly different way!  

Round 2:

  1. One person in the group is blindfolded and holds their hand ready to grab the ruler
  2. Another person holds the ruler with the 0 inch mark right above the blindfolded person’s thumb
  3. The person holding the ruler counts, “1, 2, 3, Go!” and drops the ruler on “Go”
  4. The blindfolded student listens for “Go” and grabs the ruler.
  5. Another group member takes note of how far down the ruler went and sees at what measure the student’s thumb is near and record the time using the chart.
  6. Repeat this process two more times. Students then find the average of all three trials.

**If you do not have anything to use as a blindfold, just have students put their heads down on their desks and close their eyes. This can be way easier than messing with making the blindfolds just right around kids’ heads.**

Follow up questions to ask students:

  1. Which method did you have the quickest reaction time?
  2. Was this the better method for everyone in your group? Explain.
  3. Why might some people’s reaction time be faster than others?
  4. What errors may have occurred that would affect the outcome of this experiment?

Blender Muffins

I happened to stumble upon these blender muffins when my son wanted to “cook” with me. He loves baking cookies, muffins, or anything else that uses my stand mixer. We also had a few bananas that desperately needed to be used. This time, I found a recipe that uses the blender. Intriguing!

Turns out, this recipe was super simple, gluten free (there is no flour!) with mostly healthy ingredients. And of course, pressing buttons on the blender was a huge hit with my son! He asks to make these blender muffins often!

The original recipe can be found here at 

I made a few changes and added whatever mix-ins we had to the muffins. Chocolate chips and blueberries made the list, but really, any type of nuts, berry, or even adding some peanut butter would work!

The recipe makes about 12 regular size muffins.


  • 2 ripe bananas (I usually keep overripe bananas in the freezer. Once thawed, these make excellent, moist muffins!)
  • 2 cups old fashioned oats
  • ½ cup unsweetened applesauce
  • ¼ cup Greek yogurt
  • ¼ cup brown sugar
  • 1 egg
  • 2 tbsp honey
  • 1 ½ tsp vanilla
  • 1 tsp baking soda
  • 1 tsp baking powder
  • ½ tsp salt
  • ½ tsp cinnamon

Mix-in options – almonds, walnuts, blueberries, raspberries, chocolate chips, butterscotch chips, peanut butter chips, raisins, coconut, etc.


  1. Place bananas, oats, and applesauce to the blender. Pulse for a few seconds until oats are slightly more smooth. Add all other ingredients and blend until well combined and mostly smooth.
  2. Add in any mix-ins that you would like and stir with a spatula (so the mix-ins don’t get crushed up!)
  3. Pour batter into muffin liners two thirds to three fourths full. You can add more mix-ins to the top of the batter if you would like! The muffins will rise as they  bake, but flatten out once they come out of the oven.

Bake muffins at 400 degrees for 13 – 15 minutes, or until a toothpick comes out clean.

While you can eat the muffins right out of the oven, they freeze well too, which makes a great grab and go breakfast on those busy mornings. Make sure you allow the muffins to cool completely, then put them in a Ziploc bag or wrap with a few pieces of plastic wrap. You can thaw in the fridge or by zapping them for a few seconds in the microwave.


Lung Capacity Lab

Want to know how much hot air middle school students have? Try this lung capacity lab. Students will be able to see how much air their lungs can hold!

The human body unit is once again upon us! Because I’m using a new curriculum this year, I’ve made some adjustments to how I go about teaching. However, a few labs are tried and true that I will definitely keep! This was one of them. It is so easy. Grab a balloon and a ruler for each student, and you’re set!


Giving middle school students balloons does have some risks. Be prepared to hear many balloon squeals and other noises that sound like body functions. I warned the students in advance that no balloons should be released across the room.

Now to the lab:

Once students have received their balloon, they will use it to measure how much air their lungs hold. We compare the difference between vital capacity and tidal capacity of their lungs.

Vital capacity – the maximum amount of air the lungs can hold.
Tidal capacity – the normal amount of air that your breathe in and out.



  1. Students take a deep breath and blow up the balloon as much as they can with that one breath. Hold the balloon (do not tie it!) and measure the diameter with a ruler, recording this length.
  2. To find the volume, you can use the formula for the volume of a sphere (although the balloons aren’t perfectly sphere, this gives a pretty close measurement). Or, I give my students a graph that they can use to estimate the volume like this one, which is found l here at
  3. Repeat this two more times, then find the average of all three.
  4. Next, students take in a normal breath and breathe it into the balloon. Be careful not to push too hard! This should be a normal breath.
  5. Record the diameter and then find the volume either using the formula or the graph.
  6. Repeat this two more times and then find the average diameter and average volume.

The average adult male has a vital capacity of a little more than 3000 cm3 and the average female’s vital capacity is about 2700 cm3. Of course, this also depends on height, weight, health and several other factors.

You can have students compare their lung capacities to their classmates. You can also ask follow up questions such as:

  1. What would you expect a professional athlete’s lung capacity to be? Why?
  2. What would you expect the lung capacity of someone who smokes to be?
  3. How might a musician’s lung capacity compare to others?

What a great way to lead into talking about health concerns and the importance of exercise!

Radioactive Pennies

Teaching chemistry in middle school is difficult. You can’t see atoms and you can’t feel electrons moving around.The material leans toward the abstract, even though atoms are what make up all concrete objects! To make it worse, this unit comes during the mid-winter, still not close enough to spring break time of year.

I always try to use hands-on simulations or interactive labs to help students connect to the information. (For example, these cereal Bohr model projects). Radioactive elements are another great one to simulate (I mean, you have to simulate it… highly radioactive elements are frowned upon at school). Radioactive Pennies a mini lab that can bring the concept to life. This lab uses probability and flipping coins to simulate what happens to elements that undergo radioactivity. Each round represents a half-life of the penny element. So after discussing what happens when an element becomes radioactive, students participate in this!

Materials Needed:

  • 50 pennies per group
  • Ziploc or paper bag
  • Blank graph

Instructions for Radioactive Pennies

  1. Students put all the pennies into the bag, shake, then dump them out onto the table
  2. Any pennies that land on heads are the ones that have changed elements. Put these in a pile to the side.
  3. Place all the tails back into the bag to be dumped again
  4. Repeat the process until all the “element” has changed
  5. Students record how many pennies landed heads after each round and create a line graph plotting the number of heads each time on the y-axis and rounds on the x-axis.

    This shows how many pennies were heads after each round

Comparison to a half-life of an element

Students should notice a pattern of about half the pennies being flipped to heads each round. Of course, it is not always half, but this idea is the same as an element’s half-life. It takes each element a certain amount of time to fall to half its size. It takes one round for the group of pennies to fall to half its size. From this, you can predict about how long it would take for all the pennies to flip, just as scientists can predict about how long it takes for certain elements to “fall apart.”