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Frostbite Theater

Here's a Question! - Scales in Series

Stack one scale on top of another and stand on top of them both. What will the scales read?

Announcer: Frostbite Theater presents... Cold Cuts! No baloney!

Joanna and Steve: Just science!

Joanna: Hi! I'm Joanna!

Steve: And I'm Steve!

Joanna: Here's a question for you...

Steve: One digital scale is placed on top of another.

Joanna: Each scale is then tared so they both initially read zero.

Steve: A small steel bar massing 96.3 grams is placed on the top scale.

Joanna: What does each scale read?

Steve: Does the top scale read 96.3 grams and the bottom scale read zero?

Joanna: Does the bottom scale read 96.3 grams and the top scale read zero?

Steve: Does each scale read half of 96.3 grams?

Joanna: Or, does each scale read 96.3 grams?

Steve: Pause the video now if you'd like time to think it over before we show you what happens.

Steve: The top scale fully supports the steel bar, so it displays the bar's full mass.

Joanna: The bottom scale fully supports the top scale as well as the steel bar. Normally, the bottom scale would display the mass of the top scale plus the mass of the steel bar.

Steve: But we tared the bottom scale, which reset its display to zero, when we put the other scale on top of it.

Joanna: After that, the only thing that was added to the stack was the steel bar. So, the bottom scale only displays the bar's full mass.

Steve: If they're properly calibrated and tared, scales placed in series all display the full mass of the object placed on top of the stack.

Joanna: Thanks for watching. I hope you'll join us again soon for another question!

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