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More trials! This time we need to figure out what to do if you don't have all the things you'd like to have to perform your tests. How do you isolate a variable across multiple tests? A good engineer will work to find a way to make it happen. In this episode of Crash Course Kids, Sabrina shows us some ways to do just that.

///Standards Used in This Video///
3-5-ETS1-2. Generate and compare multiple possible solutions to a problem based on how well each is likely to meet the criteria and constraints of the problem.

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Producer & Editor: Nicholas Jenkins
Cinematographer & Director: Michael Aranda
Host: Sabrina Cruz
Script Supervisor: Mickie Halpern
Writer: Jen Szymanski
Executive Producers: John & Hank Green
Consultant: Shelby Alinsky
Script Editor: Blake de Pastino

Thought Cafe Team:
Stephanie Bailis
Cody Brown
Suzanna Brusikiewicz
Jonathan Corbiere
Nick Counter
Kelsey Heinrichs
Jack Kenedy
Corey MacDonald
Tyler Sammy
Nikkie Stinchcombe
James Tuer
Adam Winnik

Welcome back ring toss champions.

You know, I was thinking about our carnival game experiment from last time. and I think we are getting pretty good at using the engineering process to come up with a solution to a problem. 

So.. Good for us. 

Now its time to mix things up a little. Sometimes engineers figure out more than one way to reach a solution to a problem. Think about our trip to the bowling alley. In order to solve the problem of getting a strike we used a ball ramp for every trial. 

But... what if someone else in another lane was waiting to use the ball ramp? Engineers aren't just brilliant at solving problems, they're also excellent at sharing.

So. In general, what if you don't have what you need. Whether It's the necessary equipment, or the right materials, or enough money - to make a certain solution that works? It means that you've gotta come up with another solution. And that mean, you have to be able to test a bunch of possible solutions that all meet the same criteria.

So. How do engineers design multiple tests, of different solutions, that produce the same outcome?


 Big question

Let's head back to our ring toss game and see. We decided that the criteria for our solution was: First, that we get the ring around the pin, and second that we need to do it in one toss. Next we thought about the variables that could affect our outcome, like the size of the ring, the height of the pin, how we toss the ring, and how far away we were from the pin.

After some though we decided to isolate the ring size as our variable, and it was go time!

We did three trials using: a small ring, a medium ring, and a large ring. And it took the large ring to get the outcomes that we wanted, and a sweet grand prize.

But that's not all, being good engineers, we kept testing out solution until we found a failure point. We learned that if we changed another variable; the distance from the pin, the large ring was not going to solve our problem anymore.

Which is okay cause I only have room for one huge stuffed platypus in my room anyway. But let's try to find a few different methods we could use to get the same results.


And let's not only make a plan, let's also make some tables. Tables are a great way to make everything organized because we are going to do a few different tests.

And we need a way to keep track of which variable we are changing in each test. Now the criteria for our solution are the same; one ring, one throw, on the pin. Boyega!!

So next let's list our variables. They are: ring size, distance from the pin, the height of the pin, and how we toss the ring (overhand, underhand, or like a Frisbee).

Now we need to pick a variable that we want to isolate. We already did the ring size so, let's choose the distance from the pin. So for our three trials we'll change how far we stand from the pin, making it one, two or three meters.

New we have to keep all the other variables the same. So let's decide what they are going to be. Let's choose the small ring, the medium height pin, and to through the ring underhand.

Okay Sabrina, start tossing

When we do our trials, we see that we get the outcome we want when we stand 1 meter from the pin. Test 1 is complete.

For our second test let's change the height of the pin between trials. So we will switch between throwing the ring at a short pin, a medium one, and a tall one.

We also need to pick what we are going to use for the variables that don't change. Let's stick with the small ring and standing 1 meter away from the pin, and tossing the ring underhand again.

Ready little me?

This time we can see that it is the tall pin that is giving us the outcome that we are looking for.

Okay, last test, this time let's change how we toss the ring between trials. So we will toss the ring underhand one time, overhand the other time, and the last time like a Frisbee. And all three times we will use the small ring, the tall pin, and stand one meter away.

Ready set toss. When we do our trials we see that it is the Frisbee throw that gives us the outcome that we want. Now if we wanted to we can mix and match to create any combination of variables that we are curious about. Like, we could try the Frisbee toss with different pin sizes, or toss the ring differently but only use the short pin.

As long as we only change one variable at a time, and still get the outcome that meets our criteria. we're totally golden



And now we know that it is possible to design several different tests that lead to the same outcome. We just have to remember to make a plan to change only one variable at a time and to keep things organized. When in doubt use engineering to solve problems. It will pass the test every time.