Design, Test, and Improve - First Grade Science
Now that you have learned about how scientists explore the world and how engineers design solutions, it is time to put your scientific thinking into real action! A design challenge is a hands-on project where you are presented with a specific problem, given a set of materials and rules, and challenged to create a working invention. Throughout a design challenge, you will experience the excitement of designing, the thrill of building a prototype, the curiosity of testing, and the satisfaction of improving your design to make it even stronger.
The Structure of a Design Challenge
Every design challenge has three key components: a clear goal, specific constraints, and defined criteria for success.
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| ANATOMY OF A DESIGN CHALLENGE |
| |
| THE GOAL The specific problem you need to solve. |
| Example: Build a bridge to hold a toy car. |
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| THE CONSTRAINTS The rules, material limits, and time boundaries. |
| Example: Only 20 craft sticks and 1 roll of tape. |
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| THE CRITERIA How you measure if the design is successful. |
| Example: Bridge must span a 12-inch gap and |
| support the car without collapsing for 10 seconds.|
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Featured Challenge: The Index Card Bridge
Let us walk through a complete engineering challenge step by step: The Index Card Bridge Challenge!
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| THE INDEX CARD BRIDGE CHALLENGE |
| |
| [CHALLENGE GOAL] |
| Build a bridge that spans across two thick books spaced 6 inches |
| apart, capable of holding as many metal pennies as possible! |
| |
| [MATERIALS ALLOWED] |
| - 3 Plain index cards (3x5 inches) |
| - 1 Strip of masking tape (12 inches long) |
| - Pair of scissors |
| - Cup of 50 metal pennies (weights) |
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Step 1: The First Prototype (Flat Card)
In your first attempt, you lay a single flat index card across the six-inch gap between the two books. You place a single penny in the middle. The flat paper immediately sags down into the gap! You add a second penny, and the bridge collapses completely to the table. Testing Result: Holds only 1 penny. Analysis: Flat paper bends easily because it has no vertical depth to resist downward forces.
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| PROTOTYPE 1: FLAT PAPER (COLLAPSES) |
| |
| [BOOK 1] =================== [BOOK 2] |
| \ (1 Penny) / |
| \ v / |
| '--[Sags Down]-' |
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Step 2: Improving the Design (Accordion Folds)
How can you make a thin sheet of paper strong without changing what it is made of? You change its shape!
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| PROTOTYPE 2: ACCORDION FOLD (CORRUGATION) |
| |
| /\ /\ /\ /\ /\ /\ /\ /\ |
| / \/ \/ \/ \/ \/ \/ \/ \ |
| [BOOK 1] ===================================== [BOOK 2] |
| |
| Folding the card into zigzags creates vertical triangular walls |
| that resist bending! This is how cardboard boxes are made! |
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The Power of Corrugation
You fold the index card back and forth like a paper fan, creating an accordion pattern with triangular peaks and valleys. Then you lay a second flat card on top of the folded folds to create a smooth roadway. Testing Result: You place 1, 2, 5, 10, 20... all the way to 35 pennies on the bridge! The accordion-folded bridge supports 35 times more weight than the flat card!
Step 3: Further Iteration and Refinement
Iteration is the process of repeating steps to continually refine a product. Can you improve the bridge even further? Adding Side Rails: What if you fold the edges of the top index card upward into L-shaped girders? Taping the Ends: What if you tape the ends of the accordion folds securely to the books so the folds cannot slide outward under heavy weight? Testing Result: With taped ends and side rails, your bridge now holds all 50 pennies without budging!
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| THE ITERATION PROGRESSION CHART |
| |
| DESIGN ATTEMPT DESIGN FEATURE PENNY WEIGHT HELD |
| Attempt 1 Flat single card 1 penny |
| Attempt 2 Accordion fold 35 pennies |
| Attempt 3 (Refined) Folded + taped rails 50+ pennies! |
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The Mindset of a Young Engineer
When you tackle design challenges, remember three golden principles: Patience: Great inventions take time. Thomas Edison tested thousands of materials before finding the right filament for the electric light bulb! Observation: Look closely at where your prototype bends, slips, or tears. That spot tells you exactly what needs to be reinforced. Creativity: Do not be afraid to try unusual ideas. Changing the shape, rolling tubes, or folding triangles can transform weak materials into remarkably strong structures.
Chapter Review Exercises
Question 1: What is a design challenge, and what are the three main components that define it?
Question 2: In the Index Card Bridge Challenge, why did the flat index card collapse under the weight of just two pennies?
Question 3: How did folding the index card into an accordion shape make the bridge significantly stronger?
Question 4: What does the term "iteration" mean in engineering design?
Solutions and Explanations
Solution 1: A design challenge is a hands-on engineering project where you build a solution to a problem. The three main components are the goal (the problem to solve), constraints (the rules and material limits), and criteria (how success is measured).
Solution 2: The flat index card collapsed because thin paper has no vertical thickness or structural depth to resist downward bending forces caused by gravity and the weight of the pennies.
Solution 3: Folding the card into an accordion created a corrugated series of vertical triangular ridges. Triangles are extremely rigid geometric shapes that distribute the downward weight across many angled columns, preventing the paper from sagging.
Solution 4: Iteration is the process of testing, analyzing flaws, modifying the design, and retesting repeatedly to make successive improvements until the best possible solution is achieved.