World's Largest T-Shirt Cannon (breaks the roof)

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What Parents Need to Know

Mark Rober's World's Largest T-Shirt Cannon video is a strong example of educational entertainment done well. Kids will learn real physics concepts — how air pressure works, how barrel length affects velocity, and how iterative engineering design solves problems — all wrapped in an exciting build challenge. The standout element is Anthony, a young inventor who designed a Lego ventilator and whose engineering ideas are genuinely incorporated into the final cannon. There is a brief moment where a friend jokes about wanting a cannon that 'could possibly kill,' which is clearly played for laughs and not dwelt upon. A real Civil War cannon is fired early in the video, and while it's treated safely and scientifically, younger or more sensitive children might find the loud bangs startling. There is no inappropriate language, no sexual content, and no substance use. The video includes a brief mention of the Jimmy Kimmel Bowl, which is a sponsored event context, but there is no overt product promotion.

Talk to Your Kids About

1. 1What were the three engineering improvements Anthony suggested, and can you explain why each one would make the cannon shoot farther?
2. 2Why do you think Mark involved Anthony in the design process instead of just building it himself? What does that tell us about how engineers work together?
3. 3The lawyers made Mark reduce the cannon's power to 25% for safety reasons — do you think that was the right call? Why is safety important even when something is really exciting?
4. 4If you could design a machine to solve a fun problem, what would it be and how would you start figuring out how to build it?

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