Activity: Goalpost design challenge

This content is provided by the 49ers Museum Education Program.

Introduction

Have you ever seen a football goalpost? Do you know what they are used for and why? To understand how goalposts are used in the game, imagine that you just changed the channel to catch the second half of a 49ers afternoon home game. You find that the 49ers are on the opposing team’s 30 yard line and are lining up to kick a field goal.

Field goals are a three-point goal made by place-kicking or drop-kicking the ball directly above the crossbar and between the opponent's goalposts. When an offense cannot score a touchdown in their first three downs, and depending on the range or distance from the goal, the team will usually opt to kick. These goalposts are vitally important because they help set a parameter for scores to be made in the game.

Consider how the goalposts are built. Take a look at the pictures below. What do they have in common, and how are they constructed? Would you consider a goalpost a structure?

Structures are systems made up of a number of components that are held or put together in a particular way. With the cross-sectional design and vertical shapes of the posts, would they be considered a structure?

If you said yes, you are correct! Every structure built, whether it is a goalpost, a chair, or even a stadium, must have the strength to support the loads (weight) and forces acting upon it and possess structural integrity to reduce the hazards of the structure collapsing.

NFL goalposts must be 18 feet, 6 inches wide, and the top face of the crossbar must be 10 feet above the ground. Most goalposts are made out of heavy-gauge steel, which means there is a lot of weight to support. The vertical posts extend at least 35 feet into the air from the crossbar, and all the pieces of the goalpost must be installed carefully and effectively to stand upright. That is why goalposts are nicknamed “uprights.”

Goalpost structural design challenge

After learning about goalposts and how they are structures that serve an important purpose, we have an exciting challenge for you!

Challenge

You must successfully design and construct the tallest free-standing paper goalpost possible using only limited materials.

Materials

2 pages of standard 8.5 x 11 inch paper
Masking tape
Yard stick/ruler/tape measure
Scissors

Criteria

Your goalpost design may only include the materials given (you can only use 40 centimeters of tape and two pieces of paper). Hint: You may have to use paper creatively (roll it, fold it, etc.).
The goalpost must be freestanding and not be attached at the base to any surface (e.g., desk, floor) and may not lean against any other surface.
You must first make an initial design before construction.
Your goalpost must stand on its own for ten seconds or longer after it is built.
The goalpost must be constructed to be the tallest it can be, based on the materials given.
There is no time limit given for this challenge. It is about following the engineering design process and refining your design through experimentation.

Step 1: Gather your materials

Step 2: Follow the engineering design process.

You need to study and understand the problem you have to solve and understand what you can and cannot do.
It is time to brainstorm. What possible shapes or designs could you use for your goalpost?
After you have come up with good ideas, pick a solution and give it a shot!

Step 3: Sketch out a goalpost design

Step 4: Construct your goalpost

Step 5: Test and refine your design

You are encouraged to test as wide a variety of goalpost designs as possible. Keep in mind, while testing, that air conditioning, open doors, and/or open windows can create breezes that can knock over your goalpost.
Were you successful? Did your goalpost design fail? No worries if it did: fail stands for First Attempt In Learning. Failure provides you the opportunity to learn and helps move you closer to your ultimate goal. Keep trying to make it as great as it can be!

Evaluation

A. Once completed, the height of your constructed goalpost will be measured from the base to the highest point.

B. The following scoring rubric allows for you to compete only with gravity and your own design:

Over 30 cm = Good
Over 40 cm = Outstanding
Over 50 cm = Spectacular
Over 60 cm = A Masterpiece of Structural Engineering & Design!

Things to think about

What would you do differently next time?
What did you enjoy about this activity?
What would you like to know more about goalposts?
What geometric shapes do you see in the completed goalposts?
Why do you suppose that certain shapes work better than others in the goalpost design?
How important were measurements in this activity?
How did your completed goalpost design compare with the real goalposts pictured above? How were your goalposts similar to those? How did they differ?
What sort of training do you think a person would need if he or she wanted to design and build real goalposts?

Extension

We further challenge you to go online to conduct more research into goalposts. There are a lot of historic events that took place that led to its current design.

We hope you enjoyed this challenge, and we hope you continue to explore how structural design impacts the world around us!

This content is provided by the 49ers Museum Education Program.

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