Archive | October 23, 2014

Day 34: Levis Jeans

Levis Tension (3)Levis Tension (2)

College-Prep Physics: Which situation is more likely to rip the Levi’s jeans?

Today we did another round of voting to get at the idea that tension in springs, strings, and ropes are constant all the way through. Today’s slides:

During which, we do one of my favorite demos: What does the middle scale read?

PhotoGrid_1382041114508

Click the picture to reveal the answer

In the end, we talk about how a seemingly unstretchable rope or spring actually stretches under tension, much like seemingly unbendable surfaces like tables deform under compression. Just like a solid can be modeled as a network of balls and springs, so can rope and string:

BallAndSpringRope

Even metal wire stretches!

##BFPM

NGSS Science and Engineering Practice #2: Developing Models
NGSS Science and Engineering Practice #6: Constructing Explanations

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