DEYSI: Today these engineers are going to use the design process to build something.

The design process is a set of steps that engineers, inventors, and other creative people use to come up with a solution.

And this is the Acera School.

Acera is a school where kids can work with their hands to solve problems.

The first step in the design process is to define the need.

Say you're at, like, the grocery store, and you're biking, right?

And then it's really hard to hold your groceries, because you're doing this.

So you have to use something that will make it easy to have it in the back.

I guess we could put the groceries in a trailer.

DEYSI: It's easy to skip past defining the need and rush into design and building.

Who's going to use this trailer, and what are they going to use it for?

Well, I'd be able to use it, and my parents probably would.

If you don't define the need, it's hard to come up with solutions that work.

- We could make it so it holds multiple things at once.

Defining the need paves the way to fulfilling the need.

So what's the next step?

Brainstorming.

DEYSI: Once an engineer or inventor understands the need, it's time to brainstorm to generate ideas and come up with solutions.

- What if we had a separate little area in the cart that was padded, so we could have eggs and other stuff like that that can get broken?

I think that's a really good idea.

We could use pressure-treated wood.

Wood might be a little bit heavy.

Aluminum?

That's what the bikes are made of.

We can't really weld aluminum together.

We might be able to use PVC pipe.

Yeah, PVC pipe, it's very light, it's going to be strong, and it's not going to fall apart.

- And also you can change the design because there's so many different sizes of it.

DEYSI: Brainstorming is about quantity.

The more ideas, the better.

Maybe there's something that's already kind of like this that we can repurpose and make it into a trailer.

- You found a trash can.

The next step is to design.

Looks like we have two ideas.

One is a trailer made out of PVC, and two is a repurposed trash can.

Designing involves sketching out your ideas, narrowing down your solutions, and giving it the NUF test-- is it new, useful, and feasible?

It's new, because I don't think anyone's ever made a trailer out of a repurposed trash can.

It's useful because you can carry groceries in it.

And it's feasible because we're actually building it.

DEYSI: The next step in the design process is actually three steps that cycle around, and may be repeated-- build, test and evaluate, and redesign.

- We decided to work on the repurposed trash can idea first.

- Almost.

Yes.

DEYSI: Yay, good job.

The trailer would bump into the bike wheel, so we can use this shopping cart as a connector between the bike and the trailer.

We already have the rack on it.

- We attached the shopping cart to the rack with two zip ties, and then we tested it.

The cart was not turning-- it just stayed straight.

Failure offers an opportunity for improvement.

It's what makes designs better and better each time.

- So we redesigned the connection using zip ties and a carabiner clip, the kind that's used in climbing.

Now the trailer pivots.

DEYSI: This is the heart of the design process-- the cycle of testing, evaluating, redesigning, and then repeating the process until the design is successful.

- Now we are starting work on our PVC pipe design.

- Elliot measured some grocery bags, and then he made a scale drawing.

- A scale drawing is when you make a drawing to the size of the actual thing you're making.

- So I'm taking the measurements from the drawing that Elliot made and marking them down on the PVC pipe.

This is PVC pipe, and these are PVC fittings.

The PVC pipe is designed to fit into the PVC fittings.

By using different lengths of pipe in different fittings, you can make lots of different designs.

- This is the basic box of our trailer.

These are two lawnmower wheels that I found in my basement, and I thought might be useful.

I'm going to put this axle through the caps that Grace and Elliot drilled holes into, and then I'm going to put the wheels on the ends.

Wow, that looks good.

What we can do is we can take the nut off, and then attach something to the nut.

I'm going to cut this piece of metal with a hacksaw and then drill a hole into this piece of PVC pipe and attach it.

That's good.

All right, let's try it out and see if it works.

- I was running behind the trailer, and I saw it would rub against the wheel of the bike.

I think we need a redesign here.

So I made an angled tow bar so it won't drag against the wheel.

So this is a hammock that I designed to put eggs in.

I used paper fasteners to attach the inner tubes to each other.

This hammock will help suspend the eggs so that they won't hit the sides or fall out.

A lot easier to carry.

I'm heavier than three bags of groceries.

Nope.

I think he's enjoying it a little too much.

This is awesome!

The final step in the design process is sharing your solution with others.

- I think that the trailer that was made out of the trash can right now is a little bit more sturdy.

- But it was bulky, it had a wide turning radius, and it didn't have, like, a way to keep eggs safe.

- But I liked the PVC pipe one better.

Yay, my eggs are safe!