Hands-on Activity Brain Power:
Exploring Reaction Time and Building Your Own Helmet

Learning Objectives

After this activity, students should be able to:

• Describe how information is collected through our senses and then processed in the brain.
• Construct a model that shows the process the brain follows to complete a task.
• Use the engineering design process to design, create and test how well a helmet made from various supplies will protect the brain (i.e., egg).

Educational Standards

Each TeachEngineering lesson or activity is correlated to one or more K-12 science, technology, engineering or math (STEM) educational standards.

All 100,000+ K-12 STEM standards covered in TeachEngineering are collected, maintained and packaged by the Achievement Standards Network (ASN), a project of D2L (www.achievementstandards.org).

In the ASN, standards are hierarchically structured: first by source; e.g., by state; within source by type; e.g., science or mathematics; within type by subtype, then by grade, etc.

NGSS: Next Generation Science Standards - Science

Materials List

Each pair needs:

• 1 ruler
• 1 pencil
• Brain Processing and Senses Worksheet (1 per student)
• (optional) 1 calculator

Each group of four needs:

• any building materials; some examples below
• electronics exploration kit (available online)
• magnetic building sticks (available online)
• LEGOs (available online)
• wood building planks (available online)
• building blocks (available online)
• interlocking disks (available online)
• building set (available online)
• Play-Doh
• helmet building supply options
• cardboard
• egg cartons
• pipe cleaners
• rubber bands
• straws
• yarn
• string
• tape
• newspaper
• bubble wrap
• cotton balls
• sponges
• pom poms
• feathers
• Popsicle sticks
• clay

For the entire class to share:

• laptop or tablet with projector to display the Brain Processing and Senses Presentation
• access to videos (as needed):
• BrainPop Nervous System (need subscription) 
• Generation Genius Brain Processing of Senses (12:23 minutes)   
• A Journey Through Your Nervous System (8:12 minutes) 

Worksheets and Attachments

Pre-Req Knowledge

Students should be familiar with the brain and the nervous system. They should also be able to name and explain their five senses.

Introduction/Motivation

Today, we're going to embark on an exciting adventure to explore how our brains work and how we can protect them. Imagine you’re catching a ball or reacting quickly to something happening around you. Have you ever wondered how your brain and senses work together to make those quick decisions?

In our first activity, we'll test your reaction time by catching a ruler dropped from a height. You’ll see how fast your brain processes the information and sends signals to your muscles to catch the ruler. Afterward, you'll build a model to represent how your brain and body work during this process. You’ll use various materials to create a model of your brain’s sensory system!

Next, we'll dive into why it’s so important to protect our brains. We’ll learn about brain safety and then engineer our own bicycle helmets using materials such as cardboard and bubble wrap. The goal is to create a helmet that will keep your brain safe from bumps and falls.

So, get ready to become brain experts and engineers. We’ll have fun experimenting, building, and learning about how our incredible brains help us react and stay safe!

Procedure

Background

The Brain: The human brain is the main control center for the nervous system. It processes information from the sensory organs and directs the muscles' responses. Although it shares a basic structure with other mammal brains, it is larger relative to body size. The largest part of the human brain is the cerebrum, which is split into two halves, the left and right hemispheres, connected by a bundle of nerves called the corpus callosum. The outer layer of the cerebrum, known as the cerebral cortex, is divided into four lobes: the frontal, parietal, temporal, and occipital lobes. Beneath the cerebrum is the brainstem, and behind that is the cerebellum. Different regions of the brain are responsible for various senses and bodily functions.

Senses: The five traditional senses are taste, smell, touch, hearing, and sight. When a sense is stimulated, specialized cells and tissues within each sense organ receive raw stimuli and translate them into signals. These signals are then sent through nerves to the brain, where specific areas interpret them as sight (vision), sound (hearing), smell (olfaction), taste (gustation), and touch (tactile perception).

Sensory Receptors: One key characteristic of living organisms is their ability to respond to stimuli. The human sensory system is highly advanced, capable of processing thousands of incoming signals at once. This complexity enables you to be aware of your surroundings and respond appropriately. Sensory receptors in your body detect these signals, reacting to various physical stimuli from your environment. Sensory receptors are categorized based on the type of stimulus they respond to. Generally, they respond to one of four main types of stimuli: chemicals (chemoreceptors), temperature (thermoreceptors), pressure (mechanoreceptors), and light (photoreceptors).

Reaction Time: Reaction time measures how quickly an organism responds to a stimulus. Although stimuli travel rapidly through the nervous system as messages, the body doesn’t react immediately. Many athletes train extensively to enhance their reaction time. Reflexes and reactions, though they might seem similar, are actually quite different. Reflexes are automatic, protective responses that are faster than reactions. They are typically part of a negative feedback loop that helps restore the body to its normal state, or homeostasis. Reactions, on the other hand, are voluntary responses to stimuli.

Before the Activity

• Collect all of the necessary materials listed in the lesson plan, including rulers, pencils, building materials for the brain processing model, and supplies for creating the bicycle helmets.
• Make copies of the Brain Processing and Senses Worksheet (1 per student).
• Set up the classroom for each activity, ensuring that all materials are organized and easily accessible. For the reaction time experiment, designate an open space where students can safely conduct the experiment without obstruction.
• Preview the educational videos to ensure they align with the learning objectives and are age-appropriate for your students.
• Familiarize yourself with materials in order to best facilitate discussions and answer questions effectively.

During the Activity

Part 1: (2 days)

1. Go through the Introduction and Motivation section.
2. Display the Brain Processing and Senses Presentation.
3. Go through the questions on (Slides 3-4).

• Do all animals have the same senses? (Answer: Many do, some don’t.) 
• Do humans use their senses for the same reasons animals do? (Answer: Yes, for survival, to find food, etc.) 
• Do you think all animals’ bodies process sensory information the same way? (Answer: Yes)
• How do animals and humans detect, process, and use information about the environment? (Answer: Animals detect things with their senses. Their nervous system sends the information to their brain, and their brain decides what action to take based on the information.)
• Do you know the system that animals use to process sensory information to their brains?  (Answer: Nervous system)

4. What are some of the ways animals' senses are the same or different from humans’? 

• Potential answers:
• For vision, many animals see light and movement, but some, like eagles, have sharper vision, while others, like cats, excel in low light.
• Hearing is another shared sense, but animals like bats and dolphins use echolocation, and dogs can hear higher frequencies than humans.
• In terms of smell, dogs have a vastly superior sense compared to humans, and some insects can detect pheromones from far away.
• Taste is used by both humans and animals to identify food, though some animals, like cats, have fewer taste buds and do not taste sweetness.
• Touch is a common sense, but animals like elephants have sensitive trunks, and whiskers in animals like cats are highly adept at detecting their surroundings.

5. You use your senses every day and you might not even be aware of it.
6. Has anyone here ever caught a ball? (Almost all students should say yes or raise their hand.)
7. Think about the steps involved in catching a ball. 

• What is the first step? (Answer: Seeing the ball coming at you, or hearing someone call your name to tell you the ball is coming at you—input from your senses.) 
• What’s the next step? (Answer: Deciding to catch the ball—your brain is thinking about your action.) 
• Next step? You react. (Answer: Your brain tells your body what to do—catch it, run away, duck, hit it back, whatever—nerve impulses travel from your brain to the rest of your body.) 
• The last step? (Answer: Your body performs the task your brain told it to do, and you catch the ball… Maybe!)

8. What is "reaction time," and how does it help an animal survive? (Answer: The amount of time it takes for a sensory receptor to send a signal to the brain through the nervous system, for that signal to be processed in the brain, and for your brain to send a signal back that causes a response, such as pulling your hand away from something slimy.)
9. What is an instinct? (Answer: A response an animal makes to an environmental stimulus that is present at birth. It is something they are born knowing and therefore does not need to be learned.)
10. Provide an overview of what students will be doing, emphasizing the objectives and the relevance of the activities to their learning.
11. Tell the class: We are now going to do an experiment called the Reaction Time Experiment. You and your partner are going to take turns. One of you will hold the ruler at the top while the other one will pretend you are going to pinch the bottom of the ruler, where it starts at 0, but you won’t touch it. Without warning, your partner will let go of the ruler and you will have to pinch it as fast as you can. Then you will write down how many centimeters passed before you pinched it. Next, you will look up the distance on the reaction time chart to find your reaction time, which you will record as well. After that, you will switch so your partner can do it. Continue this until each of you has 10 trials. If you fail to catch the ruler, then your partner will need to redo the drop until you catch it.
12. Demonstrate how to conduct the experiment, emphasizing safety precautions and proper procedure.
13. Tell the class: Before we start, we are going to make a prediction on what you think your fastest time will be, as well as your slowest time. (Slide 5 on the Brain Processing and Senses Presentation)
14. Divide the class into partners. Have the students get together with their partner and complete the experiment. Supervise as students conduct the experiment, ensuring they follow instructions and record their results accurately. Offer assistance and guidance as needed, especially for students who may have difficulty understanding the concept or performing the task. (Slide 6)

    

15. After all students have completed 10 trials, have them look at their reaction times over the course of their trials and analyze the changes, if any, across them. (They should be getting faster.)
16. Complete the “Analyzing Data” section of the Brain Processing and Senses Worksheet. (Slide 7)

• Mean (“Average”): Add up all the numbers and then divide by how many numbers there are. Write each reaction time on a line in your worksheet. Once you have added up all the numbers, divide by 10 to get the mean. You can use a calculator if needed. (Slide 8)
• Median (“Middle Number”): Order numbers from lowest to highest. Identify the middle number or the average of the two middle numbers. Write the reaction times from lowest to highest. If the number in the ( ) is the same, then that is your median; if the numbers are different, add them up and divide them by 2. (Slide 9)
• Range (“Highest Minus Lowest”): Subtract the lowest value from the highest value. Write the highest reaction time first and the lowest reaction time next. Then subtract them to find the range. (Slide 10)
• Mode (“Most Often”): Identify the number that occurs the most often. (There might be more than one.) Write the number(s) that come up the most times. If each number only comes up once, you won’t have a mode. (Slide 11)
• Outlier (“Out There”): A value in a set that is very far away from the other values. (There might not be one.) Write the number that is very far away from the other values. You might not have one; in this case, you can write no outlier. (Slide 12)

17. Have the students all give you their data for their mean one at a time. On the board, show the Analyzing Class Data Line Plot and have the students fill it in together as you call on one student at a time to share their mean. Once a student tells you their mean, place an X above that number and have the students do the same. Continue this until every student has given their mean. (Slides 13-14)

• Class Mean: Model for the students how to add up all of the students’ means and divide by how many students there are to find the class mean. They can use their calculators. (Slide 15)
• Class Median: Use the Class Reaction Time Line Plot to help you find the mean. Start by putting a dot next to the lowest number X and then one next to the highest number X. Continue this until you have one number left, or two different numbers. If you have one number left, that is your class median. If you have two numbers left, add them up and divide by 2 to find the class median. (Slide 16)
• Class Range: Write the highest reaction time first, and the lowest reaction time second. Then subtract them to find the class range. (Slide 17)
• Class Mode: Write the number(s) that come up the most times. If each number only comes up once, you won’t have a mode. (Slide 18)
• Class Outlier: Write the number that is very far away from the other values. You might not have one. (Slide 19)

18. Have students review their predictions from the beginning of the experiment and record how well their predictions match what their actual performance numbers show.  (Slide 20)

• Some example sentence starters to give the students are:
• My prediction was correct because…
• My prediction was close because…
• My prediction was way off because…

19. Questions to ask: 

• Are there any differences between your trial times? (Answer: Should be getting faster.)
• Why do we perform the experiment more than once? (Answers: More accurate results, be able to see change over time, use averages to get more reliable results.)
• If your time decreased over the 10 trials—meaning it took you less time to catch the ruler—what does that mean? (Answer: Your brain is getting faster at its processing speed, memory, and thinking skills.)
• Why was the ruler caught in the middle (after a lag period) rather than at the end (instantaneously)? (Answer: It takes your brain and body time to process what is happening and what you are supposed to do.)
• What causes this delay? (Answer: Even though the information travels very quickly along your nervous system as messages, your body doesn’t react instantly.)
• What had to happen in your body for you to catch the ruler? (Answer: Your eyes send information to your brain that says the ruler is dropping and I need to catch it. Then, your brain sends information to your fingers to squeeze shut.)
• How can your reaction time be improved? (Answer: Practice.)

Part 2 (2 days)

1. Watch one or more of these videos: (Slide 22)

• BrainPop Nervous System (need subscription) 
• Generation Genius Brain Processing of Senses (12:23 minutes) 
• A Journey Through Your Nervous System (8:12 minutes)

2. Divide students into groups of four.
3. Have students discuss and create an explanation of what was taking place in their bodies as they tried to catch the ruler. They may use words, drawings, or a combination of both. Have each group share their thoughts with the whole class to create a class explanation about how their bodies and brains worked together to catch the ruler. (Slide 23)
4. Circulate among the groups, offering support, asking probing questions, and providing guidance as needed. Encourage creativity and critical thinking as students construct their models.
5. Have each group of four brainstorm some common actions they do in their lives that are triggered by information coming in from their senses. Ask each group to come up with at least 10 different actions and identify the sense or senses that received the information. Beside each action and its senses, list how that action helps with survival in their classroom, at home, on the playground, and other places students spend time. Have them write this down on their worksheet. (Slide 24)
6. Have each group make a 3D model showing how the sensory network is involved in receiving, transmitting, and responding to input from senses. Tell them they will need to label the model with information, receptors, perception/memory, and action. (Slide 25)

• The model can be made with any of the following:

                                               i.     electronics exploration kit

                                              ii.     magnetic building sticks

                                             iii.     Legos

                                             iv.     wood building planks

                                              v.     building blocks

                                             vi.     interlocking disks

                                            vii.     building set

                                          viii.     Play-Doh

• Have each group make a sketch diagram of how they want their 3D model to look. They need to include labels and what materials they would like to use to make the model.
• You will need to approve each diagram before students can start building. This will help make sure that they have all of the parts needed.
• Once each group has had their diagram approved and built their model, have them displayed so that the students can go around the room and look at everyone’s creations.

Part 3 (3 days)

1. Go through the slides covering the importance of protecting the brain.

• Watch one or more of the videos: (Slide 27)
• BrainPop (Must have subscription) 
• Mystery Science Mini Lesson (Must have subscription; 5:11 minutes)
• Protect your Brain (Mentions addiction; 1:31 minutes)
• Why? (Slide 28)
• Your brain is in charge of your body and controls everything that you do.
• When?
• We should protect our brain whenever riding a bicycle, in-line skating, skateboarding, or playing contact sports.
• Where?
• Outside or in sports situations.
• Who?
• Everyone!
• How?
• By wearing a helmet!

2. After learning the reasons that it’s important to protect the brain, give the students various supplies (cardboard, eggs, egg cartons, pipe cleaners, rubber bands, straws, yarn, string, tape, newspaper, bubble wrap, cotton balls, sponges, straws, etc.) to construct a bicycle helmet to keep the brain protected. Students will use the engineering process as they build their helmet.
3. Go through the engineering design process with the students. (Slide 29)

• Ask (Slides 30-31)
• What is the problem?
• The brain needs protecting from head injuries (wrecks, hits, falls, etc.)
• What do we want to design?
• A helmet to protect the brain (egg)
• Who is it for?
• Students (egg)
• What do we want to accomplish?
• Protect the brain from injury
• What are the project requirements and limitations?

1. Limitations
• Two to three class periods
• Supplies given
2. Requirements
• The egg (brain) must not crack when dropped from different heights up to 5 feet.

• What is our goal?
• Create a “helmet” to protect the egg (brain) from cracking using the supplies given and within three class periods.
• Research - These resources are available for research if needed: (Slide 32)
• https://www.youtube.com/watch?v=4nvhVv5uNI0 (4:30 minutes)
• https://www.healthychildren.org/English/safety-prevention/at-play/Pages/bicycle-helmets-what-every-parent-should-know.aspx
• https://helmets.org/howmade.htm
• https://www.cdc.gov/heads-up/media/pdfs/helmets/headsup_helmetfactsheet_bike_508.pdfCDC_AAref_Val=https://www.cdc.gov/headsup/pdfs/helmets/headsup_helmetfactsheet_bike_508.pdf
•  Imagine (Slide 33)
• Divide students into groups of four.
• Have the students bring their research together and write down as many ideas and solutions that each group might want to explore.
• Plan (Slide 34)
• The students must have the majority of their group members agree on which solution they would like to move forward with.
• Make sure everyone in the groups gets to suggest an option.
• Create (Slide 35)
• The students may use any of these items to make their prototype: cardboard, egg cartons, pipe cleaners, rubber bands, straws, yarn, string, tape, newspaper, bubble wrap, cotton balls, sponges, pom poms, feathers, popsicle sticks, clay
• If there are other things that students would like to make their prototype out of that aren’t listed above, have them ask to see if it is possible.
• Test (Slide 36)
• Let the students try dropping their egg from different heights ranging from 1 foot to 5 feet.
• Have students write down their results and discuss with their team and analyze what worked and what they need to improve.
• Improve (Slide 37)
• As a group, have students discuss how they want to improve their prototype. They will make revisions and continue to test until they have a final product.

4. Test out the students’ helmets one at a time for a final test with all of the students watching.

Vocabulary/Definitions

action: The effort of performing or doing something.

information: Something that people can learn, know about, or understand.

memory: A record of a thing or an event stored and available for later use by the organism.

perception: Interpreting the input from your senses.

reaction time: The motion required for an observer to respond to the presence of a stimulus.

reaction time: A response an animal makes to an environmental stimulus that is present at birth. It is something they are born knowing and therefore does not need to be learned.

receiving: Accepting.

receptors: Receive and transduce signals.

transmitting: Sending.

Assessment

Pre-Activity Assessment

Partner Share: Have the students answer the following questions with their partner:

• What is "reaction time," and how does it help an animal survive? (Answer: Reaction time is the amount of time it takes for a sensory receptor to send a signal to your brain through the nervous system, for that signal to be processed in your brain, and for your brain to send a signal back that causes a response, such as pulling your hand away from something slimy.)
• What is an instinct? (Answer: An instinct is a response an animal makes to an environmental stimulus that is present at birth. It is something they are born knowing and therefore does not need to be learned.)

Once finished, record their answers on the board and discuss similarities and differences.

Activity Embedded (Formative) Assessment

Worksheet: Have the class work in groups of four to discuss and create an explanation of what was taking place in their bodies as they tried to catch the ruler. They may use words, drawings, or a combination of both.

Class discussion: Have each group share their thoughts with the whole class to create a class explanation about how their bodies and brains worked together to catch the ruler. 

Post-Activity (Summative) Assessment

Discussion questions:

• Which body system includes the brain and spinal cord? (Answer: Nervous system)
• True or false: A signal from your senses reaches the brain instantly. (Answer: False)
• What is reaction time? (Answer: Reaction time is the amount of time it takes for a sensory receptor to send a signal to your brain through the nervous system, for that signal to be processed in your brain, and for your brain to send a signal back that causes a response, such as pulling your hand away from something slimy.)

Safety Issues

• A potential safety concern is students misusing the rulers or other building materials, such as using them improperly or as weapons. It's important to set clear guidelines for appropriate use.

Troubleshooting Tips

• Sometimes, students may not be able to catch the ruler before it falls to the ground. To help with this, consider allowing them a practice round or two if needed.
• A potential safety concern is students misusing the rulers or other building materials, such as using them improperly or as weapons. It's important to set clear guidelines for appropriate use.
• Additionally, not all student projects will be successful on the first attempt. Encourage iteration by giving them opportunities to improve their designs. You might also allow students to observe successful projects from other groups to learn from their approaches.

Activity Scaling

• For lower grades and younger students, increase the class time to complete the activities.
• For upper grades and older students, reduce class time to complete the activities.
• For more advanced students, make more constraints and limitations to the activities.

Copyright

Contributors

Supporting Program

Acknowledgements

This work is based on work supported in part by the National Science Foundation under grant no. EEC-1801666—Research Experiences for Teachers at the University of Missouri. Any opinions, findings and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation.