Lab coats optional, curiosity required
Supply Closet Science
Episode 1 — Index Card Towers: A Simple Classroom Engineering Challenge [back]
How tall a tower can students build using only index cards? A flat card bends or falls easily, but folding, curving, or combining cards changes the way they carry a load. With only a few inexpensive materials, this activity becomes an open-ended engineering challenge that encourages creativity, testing, and improvement.
There is no single correct design. Some towers may be tall but unstable, while shorter structures may support more weight. Comparing the designs helps students see that engineers work within constraints and learn from unsuccessful attempts.
Materials
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Index cards—ten per group is a good starting limit
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Ruler or measuring tape
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Optional recording sheet
Scientific Concept
A structure’s shape affects its strength and stability. Folds and curves make a card more rigid and help transfer forces through multiple supports. A wider base usually improves stability, while added height can make a tower easier to tip. Students engage in the engineering-design process when they build, test, compare results, identify weaknesses, and revise their structures.
Applicable Virginia SOLs
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3.1a.iii: Define a simple design problem that can be solved through the development of an object, tool, process, or system.
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3.1d.ii: Generate and compare multiple solutions to a problem.
Safety Notes
Keep loose cards off the floor and the testing area clear.
Related Assembly
This challenge complements our Science of Flight Assembly, where students see how forces, materials, and design choices affect the performance of real structures and flying objects.
BOOK A BROKEN BEAKERS ASSEMBLY
Episode 2 — Test Your Reaction Time With a Ruler [back]
How quickly can your brain tell your hand to catch a falling ruler? In this simple partner activity, one person releases a ruler without warning while the other tries to catch it. The distance the ruler falls provides an easy way to compare reaction times.
The activity also turns naturally into a classroom investigation. Students can complete several trials, record their measurements, calculate an average, and discuss why results vary from one attempt to the next.
Materials
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Metric ruler or meterstick
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A partner
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Paper and pencil for recording results
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Optional calculator
Scientific Concept
Reaction time is the interval between detecting a stimulus and responding to it. The eyes detect the falling ruler, the brain processes that information, and the nervous system sends instructions to the hand muscles. Because this communication is fast but not instantaneous, the ruler falls a measurable distance before it is caught. Repeated trials also demonstrate why scientists use multiple measurements rather than relying on a single result.
Applicable Virginia SOLs
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4.2b: Animals, including humans, have structures and processes for perception and motion.
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4.1c: Interpret, analyze, and evaluate data, including measurements from repeated trials.
Safety Notes
Use a lightweight ruler with smooth edges. Participants should remain seated or stand still during the test. Release the ruler straight down, away from faces, and never throw it.
Related Assembly
This investigation pairs well with our Magical Science Assembly, where surprising results invite students to observe closely, make predictions, and use evidence to explain what happened.
BOOK A BROKEN BEAKERS ASSEMBLY
Episode 3 — The Upside-Down Cup: How Air Pressure Holds Up Water [back]
Can a full cup of water be turned upside down without spilling? Place a stiff card over the cup, invert both together, and carefully release the card. When the seal holds, the card stays in place and the water remains inside.
The result can look like a trick, but it provides memorable evidence that invisible air can exert a force. Asking students to predict the outcome before the cup is turned over makes the explanation even more meaningful.
Materials
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Clear plastic cup
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Water
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Stiff index card or piece of cardstock
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Tray, sink, or shallow container for spills
Scientific Concept
Gravity pulls the water and card downward, while atmospheric pressure pushes upward against the card. The pressure outside the cup is sufficient to support the card and water under the right conditions. Surface tension and the seal formed between the wet card and the cup’s rim help prevent outside air from entering and disrupting the pressure difference.
Applicable Virginia SOLs
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2.3a: Matter has mass and takes up space.
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2.3b: Solids, liquids, and gases have different characteristics. This demonstration provides direct evidence that air, although invisible, occupies space and exerts pressure.
Safety Notes
Use a plastic cup rather than glass. Perform the activity over a tray, sink, or water-resistant surface, and wipe up spills immediately to prevent slipping.
Related Assembly
This experiment connects directly with our Science of Flight Assembly, where students explore air pressure, airflow, lift, forces, and motion through larger visual demonstrations.
BOOK A BROKEN BEAKERS ASSEMBLY
Episode 4 — Pencil Through a Ziplock Bag: A Surprising Polymer Demonstration [back]
Pencil Through a Ziplock Bag Video
What happens when a sharpened pencil is pushed completely through a water-filled ziplock bag? Most students predict a spray of water. Instead, the bag stretches around the pencil and forms a surprisingly effective seal.
The dramatic result makes this a useful introduction to polymers and materials science. Invite students to predict the outcome first, then examine the stretched plastic around the pencil after the demonstration.
Materials
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Ziplock-style polyethylene storage bag
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Water
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Several freshly sharpened round pencils
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Tray or shallow container
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Paper towels
Scientific Concept
The plastic bag is made from polyethylene, a polymer composed of long molecular chains. As the pencil enters, its sharp point separates and stretches those flexible chains rather than tearing a large opening. The chains press closely around the pencil and create a seal. The demonstration shows how molecular structure influences a material’s observable properties, including flexibility and resistance to tearing.
Applicable Virginia SOLs
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CH.3e: Molecular geometry is predictive of physical and chemical properties. The long-chain structure of a polymer helps explain the plastic bag’s flexibility and its ability to stretch around the pencil.
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1.3a: Objects are made of one or more materials with different physical properties and can be used for a variety of purposes
Safety Notes
This should be closely supervised by an adult. Push pencils away from hands and bodies, and never allow students to aim sharpened pencils toward another person. Work over a tray and wipe up water immediately.
Related Assembly
This activity connects with our Magical Science Assembly, which uses polymers and other unexpected material behaviors to show how science can explain results that initially seem impossible.
BOOK A BROKEN BEAKERS ASSEMBLY
Episode 5 — Stronger With Folds: Build a Paper Bridge [back]
How much weight can one notecard support? Laid flat across two books, the notecard bends under even a small load. Fold that same notecard into an accordion, however, and it can support far more weight—even though no material has been added.
Students can extend the demonstration by designing their own notecard bridges. Comparing different fold sizes and shapes turns a quick observation into an authentic engineering investigation.
Materials
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Two notecards per group
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Two books or boxes of equal height
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Coins, washers, blocks, or other small weights
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Optional ruler and recording sheet
Scientific Concept
A material’s shape affects how it responds to forces. A flat sheet bends easily because it has little depth in the direction of the load. Accordion folds create ridges and supports that increase rigidity and distribute the load across the paper. Engineers apply similar principles in corrugated cardboard, roofing, bridges, and structural panels.
Applicable Virginia SOLs
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3.1a.iii: Define a simple design problem that can be solved through the development of an object, tool, process, or system.
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3.1d.ii–iii: Generate and compare multiple solutions and describe how scientific ideas apply to design solutions.
Safety Notes
Use small, lightweight objects for testing. Keep fingers and feet away from falling books or weights, and do not stack objects high enough to create a tipping hazard.
Related Assembly
This engineering investigation complements our Science of Flight Assembly, where students discover how forces, shapes, and design decisions influence the way objects perform.
BOOK A BROKEN BEAKERS ASSEMBLY
Episode 6 — Pepper and Soap: A Surface-Tension Experiment [back]
Sprinkle pepper across the surface of a bowl of water and touch the center with a clean finger. Very little happens. Touch it again with a small amount of dish soap, and the pepper quickly races toward the edges.
The pepper is not fleeing from the soap, and it is not undergoing a chemical reaction. Instead, the pepper acts as a visible marker that lets students observe changes occurring across the water’s surface.
Materials
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Shallow bowl or plate
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Water
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Ground black pepper
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Liquid dish soap
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Cotton swab, toothpick, or clean fingertip
Scientific Concept
Water molecules attract one another through hydrogen bonding, producing surface tension. Dish soap interferes with those intermolecular attractions and lowers the surface tension where it touches the water. The resulting surface-tension gradient causes movement across the surface, carrying the floating pepper with it. This is a physical interaction rather than a chemical reaction between the pepper and soap.
Applicable Virginia SOLs
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SOL 3.3a — Solids and liquids mix with water in different ways.
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CH.6c: Intermolecular forces affect physical properties. The demonstration makes the effect of intermolecular attraction on water’s surface tension visible.
Safety Notes
Use only a small amount of dish soap and avoid contact with eyes. Students should wash their hands after the activity and should not taste any materials. Wipe up spilled water promptly.
Related Assembly
This demonstration pairs well with our Magical Science Assembly, where familiar materials behave in surprising ways and students use scientific evidence to uncover the explanation.