Tinkering School

come make amazing things with us

Physics (Fall 2013)

Hands On Physics - More Predictive Power and Play

Physics (Fall 2013)Sean Murray

Last friday was a day of play and prediction. The day began with a rousing discussion about gravity. It was lead by the kids and not at all a part of the plan for the day. Then, we quickly reassembled our giant balance beam and jumped on.

Then we briefly covered the equation that dictates balance. R1*M1 = R2*M2 (wiki for more information). For the kids who understood the equation, it was powerful and enlightening. For the kids who didn't connect, it was an introduction to the notion of equations and scientific prediction. In the photo below you can see us calculating where person two (of weight M2) should stand(R2 being their distance from the center).

Our predictions were always within 2%!

An essential part of any big project is its disassembly. The goal wasn't to have a giant balance beam. The goal was to have made a giant balance beam. Having made the device and explored it properties, it was time to take it apart.

Hands on Physics and Predictive Equations

Physics (Fall 2013)Sean Murray

We warmed up with some intuition building games. We asked kids to stand at the very end of the board and adjust the board's position until balance was achieved. We marked the fulcrum point for each pair and saw how different they where.

Then it was right back to building. We had made it so far last time and this time we where determined to finish our 16 Ft teeter-totter.

From there we put panels on the top, screwed it down and were excited for our first trial of the larger than life scale.

The moment we got on our 16ft lever arm, it bent. Both sides weekly flopped the ground. The structure wasn't strong enough. Disappointment floated in the air for just a moment until Sean came up with he idea to clamp some 4x4's to the center.

It worked! The beam was sturdy and we could start balancing. Immediately the kids started figuring out how to balance themselves, and began measuring how far from the center they were and how much they weighed. Then, a game began. Josh said that all he need to know was the weight of one person, and the distance of each person from the center (when everything was in balance) and he could accurately predict the other persons weight. Super powers? Magic? No, science! We spent the rest of the day guessing weights, often within 2 lb. (2.5% error).

Next week we will unveil the mysterious equation that wielded so much predictive power.

Hands On Physics: Giant Progress on Giant Teeter-Totter

Physics (Fall 2013)Sean Murray

Today our team drew tantalizingly close to completion of our giant teeter totter.

To give us reliable information regarding our questions on levers, the teeter totter has to be built with precision.

So we use a fence...

Nathan and Bryn set a fence to make sure all the pieces get cut at the same length.

...and carefully laid out each piece to distribute mass evenly. 

The team achieved some great great workflow, distributing several tasks among team members.

We took a break from production to research exactly what we should expect from our teeter totter, and found this helpful equation... 

With any luck, we'll be using our teeter totter to answer our questions about leverage by next week! 

Hands-On Physics Day 2: From Model to Full Scale

Physics (Fall 2013)Sean Murray

Today we revisited our question: How many kids does it take to balance against an adult on a teeter-totter? The question still felt a little vague: which kids? which adult? which teeter-totter?

To help us clarify our question, and maybe reveal some issues we hadn't considered, we quickly built a model.

Kaia, Nathan, Hugo and Lux make a model with only four pieces of scrap.

The model suggested something curious: did Lux really weigh the same as Josh? 

Mass of Lux = Mass of Josh ??? 

We quickly realized that distance from the fulcrum--radius--had something to do with how the teeter-totter behaved. Specifically, the two teeterers could always adjust their distance-from-fulcrum to bring the teeter totter--even if one weighed more than double the other! 

Realizing what an interesting variable radius might be, we set to work on a 16-foot teeter-totter. 

Nathan, Trent and Hugo build the fulcrum for the second (bigger) iteration.
Isabella, Kaia and Lincoln lay out the platform.
Lux takes a break--sort of.
What is it like to be BOTH masses on the teeter-totter? Lincoln on the balance board. 

Hands On Physics, Day 1 : Good questions

Physics (Fall 2013)Sean Murray

What is science? What is physics? What is a good question? What are we doing at this class?

Hands on Physics started with a discussion on these topics. It's always our goal at Tinkering School that kids don't just walk away with a set of facts lodged away for future use, but also take steps toward developing an active system for viewing the world. In Hands on Physics the system is founded on good questions, iterative methods or experimentation and assumption that the physical world is knowable, if only we look and listen hard enough.

Sean and Josh initially proposed a terrible question "How many kids does it take to balance against josh?" The kids identified its issues. "Wait, are the kids leaning on Josh? The question isn't specific." "How are we going to measure that?" Which starts a brief discussion on units and if "kid" was a valid unit? Until we narrowed to a more specific, more measurable and more interesting question. Given a large, balanced when empty scale (like a seesaw) could we accurately predict weather or not it will be balanced when we put different people on different ends?

The question isn't finished, it still isn't clear if multiple people and weights can be on the scale, or if they have to be on the ends of the scale. But those questions will come out as we make. This led to clarity in what we are testing, and what we need to build to test it.

From there we did tool training to get ready for the big build.

Lux practicing on the shop saw

Bryn practicing on the chop-saw

Isabela practicing on the chop-saw

Maddox and Trent working on their prototype scale

Tinkering School is a trademark registered in the US Patent and Trademark Office.