What age is this video appropriate for?

This video is best suited for kids aged 8 and up. The physics concepts are explained simply, but the sledgehammer stunt and some of the more nuanced discussion about mass versus weight will resonate most with kids who have some basic science curiosity and can follow a 30-minute lesson.

Is the sledgehammer and nail stunt dangerous or scary for kids?

Mark Rober lies on a bed of nails and has a cinder block broken on his chest with a sledgehammer. He explains the physics behind why it is safer than it looks, so it serves an educational purpose. Younger or more sensitive children may find it startling, but it is not gory or gratuitous.

Does this video contain any advertising or sponsored content?

Mark briefly mentions giving away Sony headphones as prizes to viewers who share the class or submit challenge videos. It is a minor mention and not a dedicated ad segment, but parents should be aware it could prompt kids to want to participate in the giveaway.

Is the science in this video accurate?

Yes — Mark Rober is a former NASA engineer and the physics he explains (Newton's First Law, inertia, mass vs. weight, spring oscillation) is accurate and age-appropriately simplified. The video is a reliable and trustworthy science resource for kids.

Is there any inappropriate language in this video?

The language is almost entirely clean. Mark uses the phrase 'mouse fart motors' as a humorous description of small spacecraft thrusters, and says 'freaking' once. There is no strong profanity or crude humor beyond these minor instances.

What will my child actually learn from this video?

Kids will learn Newton's First Law of Motion, the concept of inertia, and the difference between mass and weight. Most importantly, they'll discover the real method astronauts use to measure their mass in zero gravity using a spring-based oscillation device — a genuinely fascinating piece of real space science.

Watchly säkerhetsgranskning

SCIENCE CLASS #5- How Do Astronauts Weigh Themselves?

Mark Rober

23:00 · 1,3 mn visningar · 3 april 2020

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Minor FlagsReviewed June 2026

3Minor Flags

6No Issues

This science lesson is safe and genuinely educational for most school-age kids, with hands-on demonstrations that make physics concepts like inertia and mass feel exciting and accessible. Mark Rober brings real NASA experience to the classroom, and the only minor notes for parents are a brief sledgehammer-on-chest stunt (framed with safety context) and a short motivational tangent about women in STEM that is positive but slightly adult in tone.

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SCIENCE CLASS #5- How Do Astronauts Weigh Themselves?

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