Mar 09, 2026
BallPit Affinity: Introducing Binding Kinetics with a Search Game (A Youth Summer Camp Activity)
- Maria Torres1,
- Yifan Tang2,
- Rebecca J Austin-Datta3,
- Eric McLamore1
- 1Biological and Agricultural Engineering, University of Arkansas;
- 2Department of Plant and Environmental Sciences, Clemson University;
- 3College of Public Health & Health Professions, University of Florida
- University of Arkansas Biosensor Engineering Lab
Protocol Citation: Maria Torres, Yifan Tang, Rebecca J Austin-Datta, Eric McLamore 2026. BallPit Affinity: Introducing Binding Kinetics with a Search Game (A Youth Summer Camp Activity). protocols.io https://dx.doi.org/10.17504/protocols.io.6qpvrne43lmk/v1
License: This is an open access protocol distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Protocol status: Working
We use this protocol and it's working
Created: March 06, 2026
Last Modified: March 09, 2026
Protocol Integer ID: 263358
Keywords: Kinetics, Affinity, BallPit!, Biochemistry, Youth, Camp, education, ballpit affinity, magnet glove, younger participant, ballpit activity, introducing binding kinetic, group size for younger participant, youth summer camp activity, ligand affinity in biological system, ligand affinity, highest affinity approach, participant, affinity capture, ball, intuitive analogy for protein, magnet, summer camp activity, protein, search game, magnet safety, gamification, participants graph performance, activity, rare target, search time as system scale increase, regarding magnet safety, mixture, student, chemical kinetic, youth age
Funders Acknowledgements:
National Institute of Food and Agriculture
Grant ID: NC1194
National Institute of Food and Agriculture
Grant ID: 2018-67016-27578
Abstract
This protocol describes summer camp activities for introducing basic concepts of biological/chemical kinetics using through gamification.
This activity models how rare targets are found in mixtures, using a BallPit activity to help reinforce the concept. The activity compares random/manual search to high-affinity capture using a magnet-woven glove. Students measure search time as system scale increases (from 50 balls → 100 balls → 200 balls → 300 balls → 500 balls).
Participants graph performance, and compute simple kinetic metrics (search rate, improvement factor). The magnet glove provides an intuitive analogy for protein–ligand affinity in biological systems. Teams compete to determine the highest affinity approach.
This activity is designed for youth ages 9th-12th grade, but may be modified for younger participants. The major modification is regarding magnet safety and group size for younger participants, reach out to our team for details.
Attachments
Guidelines
Important Safety Note: Only intact, sealed magnet-containing materials may be used. If any magnet, glove insert, or target ball is cracked, chipped, leaking, or broken, stop the activity immediately and remove the item from use. Broken neodymium magnets may produce sharp fragments and fine dust/powder that create additional hazards.
Materials
Hardware
- Duct tape
- Stopwatch(es) (phones are OK) or one official timer
- Clipboard + printed data sheets (or whiteboard table)
- Large bin for ball pit (deep enough to mix balls thoroughly)
- Magnet glove woven with neodymium magnets (or magnet wand alternative).
- Suggest purchasing pocket glove (link), wrap neodymium bar magnets in at least one layer of duct tape, insert in pouch and then sew pouch shut.
Consumables / Other
- Labels/tape for marking team IDs
- Sanitizing wipes (if shared materials)
- Pre-print Print data sheet (one per team)(see attachments)
- Eye protection (see Safety)
- Permanent marker (for labeling bins and ball sets)
- Gloves for handling magnets during setup
Troubleshooting
Safety warnings
General
- Medical devices: Keep all neodymium magnets away from pacemakers, implanted defibrillators, insulin pumps, and other implanted or electronic medical devices. Participants who may be affected should use a magnet-free alternative activity.
- Trip/fall risk: Keep the floor area around the ball pit clear and dry. No running, pushing, or diving into the pit.
Eye Protection
- Laboratory eye protection or equivalent PPE is required for all participants and instructors.
- Broken neodymium magnets can eject sharp chips or shards, which represent a serious eye hazard. If a magnet breaks, all participants should step back immediately, and the area should be secured before cleanup.
Skin
- Neodymium magnets can pinch skin, especially if two magnets or a magnet and a metal object come together rapidly.
- Broken magnets may have sharp edges or fragments that can cut skin.
- Protective gloves are required whenever handling magnetic gloves, inserts, or any suspect/broken materials.
Dust / Fumes / Inhalation
- Under normal use of intact sealed magnets, inhalation risk should be minimal.
- If a magnet breaks, do not touch, sweep, or disperse any powder or dust. Broken neodymium magnet material may generate fine particulate matter.
- If dust or powder is inhaled, move the person to fresh air and seek medical evaluation if symptoms develop or persist. SDS guidance for broken magnet dust recommends fresh air and medical attention if needed.
Ingestion
- Magnet ingestion is a serious hazard. If any magnet or magnet fragment is swallowed, seek immediate medical attention / Poison Control guidance.
- Do not minimize this as a simple stomach irritation issue. Multiple swallowed magnets can attract across intestinal tissue and cause severe injury.
Heat and Flammable Materials
- Keep broken magnet material, filings, or dust away from heat, sparks, and open flame.
- Fine powder from broken neodymium magnets may be flammable or may burn rapidly in air. If a broken magnet creates visible powder or fine debris, do not treat it as ordinary trash during the activity.
- Follow your institutional hazardous-materials or EHS procedure for cleanup and disposal.
Emergency Response / Cleanup
If a magnet breaks:
- Stop the activity immediately.
- Keep participants away from the area.
- Do not allow participants to pick up fragments by hand.
- Cleanup should be performed by the instructor or trained staff wearing PPE.
- Remove all damaged materials from service and do not reuse them.
If there is concern for ingestion, eye exposure, breathing difficulty, or other injury, seek immediate medical attention and contact Poison Control or emergency medical services as appropriate.
Before start
Materials preparation
- Pre-count and bag sets of balls or stage them in labeled bins: 50 balls → 100 balls → 200 balls → 300 balls → 500 balls
- Print data sheet (one per team); template provided in Attachments
Prepare the target ball:
- Cut open one of the colored balls (small slit approximately 1 inch long). Wrap a neodymium magnet in duct tape with at least one layer to reduce chances of fracture. Insert bar magnet into slit. Duct tape the ball and be sure it is completely sealed. The completed target ball should be visually and tactilely indistinguishable from the other balls.
Activity management
- Create a clear rule and prepare to enforce periodically during activity: Search ends when target is retrieved and shown to timer.
- Decide whether students may “shake-to-listen” (recommended: yes, but for younger participants not recommended to limit risk of broken magnet exposure)
Ensure adequate PPE and prepare to reinforce proper PPE safety:
- Wear eye protection at all times.
- Wear protective gloves and lab coat at all times.
Teams conformation
1h
Organize Teams and Establish Roles
- This protocol is designed for groups of up to 40 youth.
- For a group of this size, 3–5 leaders should be available to circulate and support teams throughout the activity.
- Divide participants into teams of 2–4, with four members per team being ideal.
Note
Optional Learning Goal Assessment: If learning assessment is included in activity, the learning objectives below are suggested.
By the end of this activity, participants will be able to:
- Collect replicated timing data and create clear graphs (time vs number of balls; rate vs number of balls).
- Calculate basic "kinetic-style" parameters including search rate, improvement factor, and normalized search time.
- Explain an analogy between magnetic capture and protein affinity/binding using plain-language concepts (encounter, capture probability, selectivity).
5m
Assign rotating roles
- One participant is the timekeeper
- One participant is the data collector
- One youth is the seeker
- One youth is the safety officer
5m
Explain the Rules of Engagement
- The goal of this activity is to find the single target ball as quickly as possible.
- Standardize mixing method: After each round, use a consistent method for remixing balls in bin (e.g., 10 “stirs” or 15 seconds of mixing between trials).
Note
Regardless of team size, use the same number of searchers per team
for all trials.
Prepare search bins
- If not prepared, count and bag sets of balls or stage them in labeled bins: 50 balls → 100 balls → 200 balls → 300 balls → 500 balls
Figure 1. Schematic step by step magnetic ball preparation
- Cut open one of the colored balls (small slit approximately 1 inch long). Wrap a neodymium magnet in duct tape with at least one layer to reduce chances of fracture. Insert bar magnet into slit. Duct tape the ball and be sure it is completely sealed. The target ball should be visually and tactilely indistinguishable from the other balls (see Fig. 1).
Safety information
Always inspect magnets for physical and/or chemical damage. Damaged magnets can create a visible powder or fine debris, which should not be handled by untrained personnel. Follow guidelines in Warning section carefully and handle magnets with caution .
Baseline Search (Manual Seek)
- Fill the pit with 50 balls and mix using the standard method. Scale up through each bin size (100 → 200 → 300 → 500) in order.
- All participants take their assigned positions before each trial.
- Data collector records participant names on the datasheet prior to starting (see attachments)
- Start timer when the seeker's hands enter the pit; stop when the target ball is lifted above the rim.
- Record search time in seconds.
- Safety officer monitors for hazards throughout.
- Run 2–4 trials per bin size to calculate a reliable mean.
Note
If available, five separate bins may be set up prior to the activity
25m
Scale up manual search
- Repeat all five bin-size trials from Step 2 in the same order (50 → 100 → 200 → 300 → 500 balls), with the seeker now wearing the magnetic glove.
- All other roles, timing rules, and mixing methods remain unchanged.
Note
Record keeper should carefully note the amount of balls for each search, and then names of the participants
Assisted Search (Magnetic Glove)
- Repeat the same five trials from step 2, but with the seeker wearing the magnetic glove
- All other roles, timing rules, and mixing methods remain unchanged.
commercial magnetic gloves may be used if customization is not possible. Note that the magnets are positioned on the back of the glove.
Safety information
Always inspect magnetic gloves for physical and/or chemical damage. Damaged magnets can create a visible powder or fine debris, which should not be handled by untrained personnel. Follow guidelines in Warning section carefully and handle magnets with caution .
Analyze data
25m
Prepare Graph 1: Mean Search Time vs Number of Balls
- Collect the data for each team member
- For each BallPit, calculate the average search time for both manual search and assisted search
Average = Sum of Data Values ÷ Number of Values
- Optional: Calculate the standard deviation of the search time for both manual and assisted search
Prepare a scatterplot with the following:
- X (independent variable): N balls (number of balls)
- Y (dependent variable): Average search time for team (s)
- Optional: Plot error bars for each average time (represnting one standard deviation)
- Include two series: Manual and Assisted
Expected result
An example plot is shown below
Graph 1. Plot of average search time versus the number of balls in BallPit. Assisted search was faster than manual search, which is due to the affinity of the magnetic glove for the ball. Error bars represent one standard deviation of the arithmetic mean.
- Inspect the graph and be prepared to discuss its shape with your team.
- In one or two sentences, write down the main conclusion you can draw from this graph. What does the relationship between search time and number of balls tell you about each search method?
Prepare Graph 2: Effective Search Rate vs Number of Balls
- Calculate the effective search rate using the following equation:
Note
Search Rate Equation:
SReff = N/mean search time
where:
N=number of balls in bin
SReff = Effective search rate (units of balls/second)
Prepare a vertical bar graph with the following:
- X (independent variable): Search Type
- Y (dependent variable): Search rate (balls/second)
Expected result
An example plot is shown below
Graph 2. Search Rate as a function of Search Type. The average search rate for Assisted Search (R^2=0.89) was higher than Manual Search (R^2=0.83).
- Inspect the graph and be prepared to discuss its shape with your team.
- In one or two sentences, write down the main conclusion you can draw from this graph. What does the relationship between search time and number of balls tell you about each search method?
Note
Compare the shapes of Graph 1 and Graph 2. If the trends differ between the two graphs, write down a possible explanation for why this occurred in your experiment.
Prepare Graph 3: Kinetic Parameter (Search Time)
- Calculate the mean total search time across all trials for both manual and assisted search.
- Plot mean search time for each search type as a bar graph (manual vs. assisted).
- Optional: add error bars representing one standard deviation to each bar (1SD)
- Inspect the graph and be prepared to discuss its shape with your team.
- Calculate the effective search rate for each BallPit size using the equation below.
Expected result
An example plot is shown below
Graph 3. Example plot of average search time across all experiments. Error bars represent one standard deviation of the arithmetic mean
Note
Instructor Note: The average improvement factor across all bin sizes serves as a proxy for binding affinity, the higher the value, the greater the advantage conferred by the magnetic glove.
When discussing results, introduce the concept of rate constants (how fast a reaction or search proceeds) and note that the improvement factor is dimensionless, meaning it has no units because it is a ratio of two times.
Prepare Graph 4: Kinetic Parameter (Affinity)
- Calculate the improvement factor (Affinity) as follows:
Improvement factor (IF) = Tmanual / Tassisted
where:
Tmanual = mean time for all manual search in a given bin size [sec]
Tassisted = mean time for all assisted search in a given gin size [sec]
- Prepare a graph of Improvement Factor versus bin size
- Calculate the average improvement factor across all bin sizes (affinity)
- Optional: calculate the standard deviation of the improvement factor
Expected result
An example plot is shown below
Graph 4. Improvement Factor in different BallPits. The average improvement factor (affinity) was 2.2 with a standard deviation of 0.3
Summarize data and prepare a short statement.
- Each team should work together to analyze the data and reflect on the experience
- Work as a group to summarize the key feature of the following graphs, and note how this relates to the conclusion
Graph 1- Average Search Time
Graph 2- Search Rate
Graph 3-Average Search Time
Graph 4-Improvement Time
Note
Using your graphs, write a summary statement that tells the full story of your experiment. Use the structure below as a guide:
"Graph 1 indicates [how search time changed with bin size], which is supported by [what the search rate showed] in Graph 2 and [what the average search time showed] in Graph 3. Therefore, Graph 4 indicates [what the improvement factor tells us about the affinity of the magnetic glove]."
The summary should explain not just what each graph shows, but how they all connect to support one overall conclusion.
Discussion Questions
Instructors may use the following notes to guide discussion
Note
Instructor Note: Close the activity by reinforcing these three core principles:
- Encounter: the target must come close enough to be detected.
- Capture probability: once close, does the searcher "stick" or "miss"?
- Selectivity: does the searcher capture only the right target, or does it pick up wrong ones too?
Connecting to the bigger picture:
In the manual search, encounters are random and capture probability is low — the searcher may handle many wrong balls before finding the target. With the magnetic glove, encounter still matters, but capture probability becomes very high within a defined "capture radius," which is why performance improves so dramatically.
Analogy to protein binding:
In a living cell, a protein is surrounded by thousands of molecules, most of which are not its target, just like the pit is full of non-target balls.
Proteins are effective because when the right molecule comes close, it binds strongly and rapidly. This "stickiness" is called affinity. Importantly, affinity is strong but not permanent, much like a magnet, the molecule can bind and release, which is essential for biological function. Higher affinity means higher capture probability once the right molecule is nearby, which translates directly to faster, more selective binding.
Discussion Questions:
- Why does search time increase with the number of balls in the manual condition? Does the same pattern hold for the glove condition? Why or why not?
- Why does the magnetic glove maintain a more consistent search time as the number of balls increases?
- Which part of the search process is truly random in each condition, the encounter, the capture, or both?
- In a biological system, what might correspond to "increasing the capture radius" of the glove? Think about protein structure or concentration.
- What would cause a "false positive" in a biological binding system, that is capturing the wrong molecule, and what was the analog in this activity?
Clean up
- Count all balls back into their labeled sets (50, 100, 200, 300, 500) and confirm counts before storing.
- Inspect the magnetic glove and all magnets for cracks, chips, or any signs of damage. Remove any damaged materials from service immediately.
- Store the target ball separately from the pit balls in a labeled container to prevent mix-up between sessions.
- Wipe down all shared surfaces and equipment with sanitizing wipes.
Acknowledgements
The authors acknowledge financial support from NIFA v: Biosensors and NIFA Agriculture and Food Research Initiative Competitive Grant no. 2018-67016-27578 awarded as a Center of Excellence. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institute of Food and Agriculture nor the National Science Foundation.