Table of Contents
- Introduction
- The Classic Penny Boat Challenge: Understanding Buoyancy
- The Water Drop Challenge: Exploring Surface Tension
- Penny Bridges and Towers: Structural Engineering
- The Chemistry of Cleaning: Shiny Penny Science
- Math and Measurement with Pennies
- Integrating Art: The Penny Spinner
- Tips for Success in Any STEM Challenge
- Bringing STEM into the Kitchen
- Conclusion
- FAQ
Introduction
Finding a jar of loose change on the kitchen counter usually means it is time for a trip to the bank. For a curious child, however, that jar is actually a treasure chest of scientific potential. We often look for high-tech gadgets to teach kids about the world. Yet, some of the most profound lessons in physics, chemistry, and engineering can happen with just a few copper-colored coins and common household items. At I'm the Chef Too!, we believe that the best learning happens when children can touch, build, and even taste the concepts they are studying.
This guide will walk you through several variations of the penny STEM challenge to help your family explore complex ideas through simple play. Whether you are a parent looking for a rainy-day activity or an educator seeking a low-cost classroom experiment, these challenges provide the perfect "edutainment" experience. By using pennies to explore concepts like buoyancy, surface tension, and structural integrity, we turn a mundane object into a powerful teaching tool. For more hands-on STEM inspiration, explore these penny STEM challenge activities.
Quick Answer: A penny STEM challenge is a hands-on activity where children use coins to explore scientific principles. Common versions include building foil boats to test buoyancy, stacking towers to study gravity, or drops of water on a coin to see surface tension.
The Classic Penny Boat Challenge: Understanding Buoyancy
One of the most popular ways to start a penny STEM challenge is by building a boat. This activity introduces children to the concept of buoyancy—the upward force that keeps things afloat. It is a fantastic way to see how shape and surface area affect how much weight an object can carry.
Why Do Things Float?
When your child places a flat piece of aluminum foil on water, it might float. But if they crumple that same piece into a tight ball, it often sinks. This happens because of displacement. For a boat to float, it must displace a weight of water equal to its own weight. By shaping the foil into a boat with high sides and a wide bottom, we increase the amount of water it pushes out of the way.
In our Erupting Volcano Cakes kit, we explore how different substances react and move. The penny boat challenge follows a similar logic. It helps kids visualize how forces like gravity (pulling the pennies down) and buoyancy (pushing the boat up) work in a constant tug-of-war.
Setting Up the Challenge
To get started, you only need a few basic supplies. This is a "mess-managed" activity that works well at the kitchen table or in a classroom plastic bin.
Supplies Needed:
- A large bowl or plastic tub filled with water
- Squares of aluminum foil (roughly 6x6 or 8x8 inches)
- A large stack of pennies (aim for at least 50 to 100)
- Paper towels for drying off coins
Step-by-Step Process: Step 1: Design and build. / Give your child one square of foil and ask them to create a vessel that can hold as much weight as possible. Encourage them to think about the shape of real cargo ships or barges. Step 2: The initial float test. / Gently place the empty boat on the surface of the water. If it tips or takes on water immediately, it is time for a quick redesign before adding weight. Step 3: Adding the cargo. / Begin adding pennies one by one. It is important to place them gently and distribute the weight evenly across the bottom of the boat. Step 4: Observation and recording. / Count each penny out loud. Stop once the boat "sinks to the bottom of the sea." Note the final number and look at where the water first entered the boat.
Engineering Improvements
The first boat rarely holds the most pennies. This is where the engineering design process truly begins. Ask your child what happened right before the sink. Did the boat tip to one side? Did the walls collapse?
For another hands-on lesson about floating materials, try this foil boat STEM activity.
Key Takeaway: Buoyancy is about spreading weight over a large surface area so the water can push back effectively. The wider and more balanced the boat, the more pennies it will hold.
The Water Drop Challenge: Exploring Surface Tension
If you want a penny STEM challenge that feels like magic, look no further than the water drop experiment. This activity focuses on the "skin" of the water, known as surface tension. It is a quiet, focused task that rewards patience and a steady hand.
The Science of Cohesion
Water molecules are very "sticky." They like to cling to each other through a process called cohesion. On the surface of a penny, these molecules hold onto each other so tightly that they create a dome shape. They will continue to pile up until gravity finally breaks the "skin" of the water, causing it to spill over the edge.
This concept is similar to how we look at ingredient density and mixtures in our Galaxy Donut Kit. Understanding how liquids behave helps children become better observers of the world around them, whether they are in a lab or a kitchen.
How to Conduct the Experiment
This challenge is excellent for developing fine motor skills. It requires a gentle touch and careful counting.
Supplies Needed:
- Clean, dry pennies
- An eye dropper or a small pipette
- A small cup of water
- A flat, level surface
Step-by-Step Process: Step 1: Level the penny. / Place a penny flat on the table. Make sure the surface is not tilted, or the water will slide off one side prematurely. Step 2: Drop by drop. / Squeeze one drop of water onto the center of the penny. Watch how it sits right in the middle without spreading to the edges yet. Step 3: Build the dome. / Continue adding drops slowly. Encourage your child to look at the penny from the side. They will see a clear bubble or "dome" forming on top of the coin. Step 4: The breaking point. / Keep counting until the water finally breaks its tension and flows onto the table.
For additional ideas, explore these surface tension experiments for kids.
Variables to Test
To make this a true scientific inquiry, try changing one thing at a time. Does soapy water hold as many drops as plain water? What about salt water? These small changes teach children about how different substances can interfere with molecular bonds.
Bottom line: Surface tension allows water to stay together in a dome shape due to cohesive forces between molecules, and a standard penny can often hold 30 to 40 drops of water before spilling.
Penny Bridges and Towers: Structural Engineering
Not every penny STEM challenge involves water. Some of the best activities focus on gravity and balance. Using pennies to build structures teaches children about the "center of gravity" and how weight must be distributed to keep a building standing.
The Center of Gravity
Every object has a point where its weight is perfectly balanced. In a stack of pennies, the center of gravity is usually right in the middle. As the stack gets taller, even a tiny tilt moves that center of gravity outside the base of the stack, causing it to topple.
When we design our kits, like the Wild Turtle Whoopie Pies, we think about how layers fit together to create a stable and beautiful result. Building with pennies uses those same principles of alignment and balance.
Building the Tallest Tower
This is often turned into a friendly competition. It sounds simple, but it is surprisingly difficult to stack more than 25 or 30 pennies perfectly straight.
Activity Steps: Step 1: The steady base. / Start on a hard, non-carpeted surface. A table is usually best. Step 2: Vertical alignment. / Place pennies one by one. Instruct your child to look at the stack from two different angles to make sure it isn't leaning. Step 3: Environmental factors. / Talk about how a small vibration—like someone walking past or a heavy breath—can knock the tower over. This introduces the idea of external forces in engineering.
The Penny Bridge Challenge
This version adds a level of complexity by introducing a gap. How do you get pennies to stay suspended in the air between two supports?
Supplies Needed:
- Two stacks of books or wooden blocks
- A single sheet of printer paper
- Plenty of pennies
The Goal: Place the paper across the two supports. Now, try to stack pennies on the paper in the middle of the gap. Most likely, the paper will sag and fall immediately. Now, ask your child to "engineer" the paper to be stronger. If they fold the paper into an accordion shape (pleats), it becomes much more rigid. This corrugated design can hold a surprising amount of weight.
For another approach, try this penny bridge STEM challenge.
Myth: A single sheet of paper is too weak to hold a heavy load. Fact: By changing the shape of the paper (through folds or arches), you can significantly increase its weight-bearing capacity.
The Chemistry of Cleaning: Shiny Penny Science
Pennies change over time. New ones are bright and shiny, while older ones are dull and brown. This penny STEM challenge turns into a chemistry lesson. It explains why metals change color and how we can use household acids to reverse the process.
Understanding Oxidation
The brown "grime" on a penny isn't just dirt; it is a chemical called copper oxide. When the copper in the penny is exposed to oxygen in the air, they bond together. This is a slow chemical reaction. To "clean" the penny, we need to provide a new reaction that breaks those bonds.
In our subscription, The Chef's Club, we often explore how acids like lemon juice or vinegar interact with other ingredients to create bubbles or changes in texture. The penny cleaning experiment is a perfect non-food introduction to these concepts. Families who enjoy these monthly discoveries can join The Chef's Club.
The Cleaning Experiment
This is a visual and satisfying activity. Kids love seeing a dark, "dirty" penny transform back to its original copper glow in just a few minutes.
Supplies Needed:
- Dull, brown pennies
- 1/4 cup white vinegar
- 1 teaspoon salt
- A shallow glass or plastic bowl
- Paper towels
Step-by-Step Process: Step 1: Create the solution. / Mix the salt and vinegar in the bowl until the salt dissolves. The vinegar is an acid, and the salt helps it react more quickly with the copper oxide. Step 2: The half-and-half test. / Hold a penny so only half of it is submerged in the liquid for about 20 seconds. Pull it out and look at the difference. The submerged half should be significantly brighter. Step 3: The full soak. / Drop the rest of the pennies into the bowl. Let them sit for five minutes. Step 4: The rinse. / Take the pennies out and rinse them under cool water. If you don't rinse them, a different reaction will occur, and they might turn a pale green color over the next hour!
Why Do They Turn Green?
If you skip the rinse step, the copper atoms react with the oxygen in the air and the chlorine from the salt. This creates a green coating called malachite. This is exactly what happened to the Statue of Liberty! It was originally a shiny copper color, but decades of exposure to the elements turned it the iconic green we see today.
Key Takeaway: Chemical reactions can change the appearance of matter. Acids like vinegar can break down oxides, while further reactions with salt and air can create new compounds like malachite.
Math and Measurement with Pennies
A penny STEM challenge can also be a fantastic way to practice math skills. Because pennies have a consistent weight and value, they are perfect for teaching measurement, estimation, and large-number multiplication.
Weight and Scale
A modern US penny weighs exactly 2.5 grams. This makes them a perfect "standard unit" for kids who are learning about mass. If you have a kitchen scale, you can use pennies to weigh other small objects. "How many pennies does this glue stick weigh?" is a much more engaging question for a child than just reading a number on a screen.
The Power of Estimation
Estimation is a critical part of the scientific method. Before starting any penny STEM challenge, we should always ask for a hypothesis.
- "How many pennies do you think this paper bridge will hold?"
- "How many pennies will it take to fill this small jar?"
After the activity, compare the actual result to the estimate. This helps children develop a better "feel" for numbers and physical space.
Calculating Immense Numbers
For older children, pennies can help visualize the scale of the economy. If $100 worth of pennies weighs about 55 pounds, how much would $1,000,000 worth of pennies weigh? These "word problems" become much more interesting when there is a physical coin to hold in their hand.
For more coin-based learning ideas, explore these creative money STEM activities.
Bottom line: Using pennies as a unit of measurement helps bridge the gap between abstract math and the physical world, making concepts like mass and volume easier to grasp.
Integrating Art: The Penny Spinner
To truly embrace the "edutainment" philosophy we value at I'm the Chef Too!, we should always look for a way to add a creative or artistic element. The penny spinner challenge blends physics with color theory and design.
Centripetal Force and Motion
A penny spinner is a simple top. When you spin it, the centripetal force keeps the penny balanced on its edge. This is a great way to talk about motion and kinetic energy. But the real fun comes from the visual effect of the spin.
Supplies Needed:
- Sturdy cardstock or a small paper plate
- Markers or crayons
- A penny
- Scissors
How to Build It: Step 1: Create a circle. / Cut a circle about 3 or 4 inches wide from your cardstock. Step 2: Design the art. / Use markers to draw patterns on the circle. Suggest spirals, dots, or different colored wedges. Step 3: Add the "axle." / Cut a tiny slit in the exact center of the circle. The slit should be just slightly smaller than the penny. Step 4: Assembly. / Push the penny halfway through the slit. It should fit snugly. Step 5: The spin. / Hold the top of the penny and give it a quick twist on a flat surface.
As the spinner turns, the individual colors will blend together. If your child colored one side blue and the other side yellow, the spinning top might look green! This introduces the basics of color theory and how our eyes process fast-moving images.
Tips for Success in Any STEM Challenge
When you are leading a penny STEM challenge at home or in the classroom, the goal isn't just to get the "right" answer. The goal is to foster a sense of wonder and a willingness to try again when things fail.
Embrace the Mess
Many of these activities involve water or small piles of coins that might end up on the floor. Setting expectations early—like keeping the water in the bin—is helpful, but don't let the fear of a small spill stop the fun. Learning is often a little bit messy.
Ask Open-Ended Questions
Instead of telling your child why the boat sank, ask them what they saw.
- "Where did the water first touch the pennies?"
- "What do you think would happen if the boat was taller?"
- "Why did the tower fall to the left instead of the right?"
Document the Journey
Encourage your child to keep a "Lab Notebook." They can draw pictures of their boat designs and record the number of pennies each one held. This reinforces the idea that science is a process, not just a one-time event.
Bringing STEM into the Kitchen
At I'm the Chef Too!, we see the kitchen as the ultimate laboratory. Every time you bake a cake or mix a sauce, you are performing a series of STEM challenges. You are measuring (math), watching chemical reactions (science), and designing a final product (art and engineering).
The penny STEM challenge is a perfect "appetizer" for the types of adventures we offer in our monthly kits. By starting with simple household items, you build the confidence your child needs to tackle more complex projects later. Whether they are building a bridge out of coins or baking a themed dessert, the core skills remain the same: observation, trial and error, and the joy of discovery.
If your family enjoys these types of hands-on activities, you might find that a more structured adventure is the next logical step. Our kits provide all the specialty supplies and pre-measured ingredients needed to take these concepts to the next level. It turns a standard afternoon into an immersive educational experience that the whole family can enjoy together. You can explore the full kit collection when you're ready for another project.
Conclusion
The humble penny is much more than just a cent; it is a gateway to understanding the physical laws of our universe. From the "skin" of a water droplet to the structural integrity of a paper bridge, these simple challenges make complex science accessible to everyone. We hope these activities help spark a new curiosity in your home or classroom, moving learning away from screens and back into the hands of eager young scientists.
- Buoyancy is taught through foil boat designs.
- Surface tension is revealed through the water dome experiment.
- Structural engineering is explored through towers and bridges.
- Chemistry is discovered by cleaning copper oxide with household acids.
Key Takeaway: Hands-on learning with familiar objects like pennies builds lasting confidence and a deeper understanding of STEM concepts than passive observation alone.
The mission of I'm the Chef Too! is to make every learning moment delicious and engaging. Whether you are using our monthly subscription or trying a simple penny challenge on your own, the goal is to create joyful memories while building real-world skills. Ready to dive deeper into the world of "edutainment"? Consider joining The Chef's Club to receive a brand-new STEM cooking adventure at your door every month.
FAQ
What is the purpose of a penny STEM challenge?
The primary goal is to help children learn scientific and engineering principles through hands-on experimentation. By using a common, low-cost item like a penny, kids can visualize forces such as buoyancy, gravity, and surface tension in a way that feels like play rather than a formal lesson.
How many drops of water can a penny usually hold?
On average, a standard penny can hold between 30 and 40 drops of plain water before the surface tension breaks. This number can vary based on how level the surface is, how large the drops are, and whether the water has any additives like salt or soap. Families looking for more related activities can explore these water-based STEM experiments.
Why do some foil boats hold more pennies than others?
The capacity of a foil boat depends on its volume and surface area. A boat that is wider and has higher sides will displace more water, creating more upward buoyant force. Even weight distribution is also key; if the pennies are all on one side, the boat will tip and sink prematurely.
Can these penny challenges be used in a classroom setting?
Yes, these activities are perfect for classrooms or homeschool co-ops because they use inexpensive, readily available materials. They align well with NGSS (Next Generation Science Standards) by encouraging students to use the engineering design process: building, testing, and improving their models based on observations. Educators can also explore school and group programmes for additional hands-on learning opportunities.
