[Light music plays, screen reads 'STEM Education'.]

Glenn

Hi, I'm Glenn. Thanks for joining in on this awesome STEM challenge.

[High-energy rock music plays. Screen depicts the 8 steps in the Engineering Design Process as cogs in a circle.]

Whether you're a beginner or a pro, the design process looks much the same. This series of five videos will step you through the iSTEM design process.

Let's begin at define, seen here as the blue cog.

Defining a design problem means to understand it from inside out.

The challenge is on, ladies and gentlemen, to design a device that will dunk a teabag, and it must be made from whatever you've got lying around your home.

[Overlay reads 'Think about... Types of motion'. Speaker is dunking a tea bag into a mug.]

Here's a teabag. We know that the teabag is going to need to move inside the cup. So we're going to need some motion. Traditionally, it's jiggled up and down in a straight line, which is called linear motion. When it moves backwards and forwards, it's called reciprocating.

The superpower of a designer is always asking questions. For instance, could the teabag move in an oscillating motion? Or could it move, perhaps, in a circular motion? Just because it's always been done that way doesn't mean that it can't change.

So, what about if the teabag stayed still and the cup moved up and down? That sounds ridiculous, but thinking about things in a fun way can often open up our minds to consider possibilities that we might not have.

Let's look at this challenge from the teabag's point of view.

[Overlay reads 'Think about.... Displacement of the teabag'. The speaker has secured a rule to the mug with an elastic band.]

When it gets jiggled, it moves from the bottom of the cup to somewhere near the top.

Let's say this is the water level.

[Speaker draws a line on the mug to signify the water level.]

I'm going to move from the bottom. [Demonstrates dunking teabag motion on the outside of the mug.] Maybe like this.

In which case, I'd be moving a total of 40mm. That's called displacement, when it's moving from one point and finishing there. Let's compare that to a smaller cup. With this traditional teacup, if I moved 40mm, I'd probably be splashing lots of tea out of the cup, and I don't want that.

So let's have a look. If I go from the bottom and jiggle. I say I'm going a maximum of 25mm displacement [for the small cup].

[Bouncing sound effect. Overlay reads 'Think about... How many jiggles are needed?']

I surveyed all of the tea drinkers in the house and found out how many times they like to jiggle a tea bag each time they make a tea.

[Survey results for three people in the house: 10, 11 and 15 times.]

[Crashing sound effect. Overlay reads 'Identify your constraints Construction materials'.]

I need to make this project out of things that everyone would commonly have in their house, so I made a collection.

And here's what I've found. Food packaging is really common. So I'm going to constrain or limit myself to just using what's around the house. That puts it on a level playing field for everybody taking part in this challenge.

[Overlay reads 'Folio record your design ideas.']

I really want to keep a record of my design journey, so I'm going to make some sketches and notes in what's called a design folio. I'm analysing this problem by breaking it down into smaller challenges and I think creating the type of motion that we're going to use.

I'm going to use linear motion and also how to provide power. I'm not going to use batteries and motors. I'm going to try and make a mechanical powered device.

And finally, everything that I've learned from my analysis, I'm going to use to write a design brief. That's a really quick description of exactly what the problem is, how I'm going to approach it, and importantly, my constraints that I'll need to work within.

[Design brief – Jiggler machine

Design and make a magine that will 'jiggle' a tea bag between 10 and 15 times.

• It should not splash tea from the cup.
• It should be easy to attach the tea bag
• It should be easy to operate/reset the machine.

Challenge A – must not use electrical power, made from recycled packaging, stationary, common household items.

Challenge B – May use construction sets (Lego, Meccano etc.) and may use electrical parts (motors, controllers)']

So if you're taking part in Challenge A, you'll be using things like rubber bands, paper clips, straws are useful, even pencils, sticks, skewers, cardboard, hot glue, tape. You might find some tubing, balloons, wire, any of that kind of stuff that isn't usually made for constructing something out of.

How about a dinosaur? Yes! [Speaker holds up a small, plastice figurine of a dinosaur.] A dinosaur's okay because it's not usually used in constructing things. So that's cool.

If you are really keen to use things like batteries and wires, electric motors and switches to make things run, Then you are looking at option B. For option B you also can use things like these microcontrollers.

There's a little chip that can be programmed like this micro bit and it can control electric motors, servos that can move backwards and forwards, lights, all that sort of thing.

Thanks for watching guys.

[Visual depicts the steps in the Engineering Design Process, 1. Define and 2. Identify are highlighted.]

In this video we've defined the challenge, we've identified constraints, which allowed us to write out a design brief.

You can copy this design brief down into your folio. So that you're ready for the next step, 'Brainstorm multiple solutions'. Seen here in orange, it's the cog with the lightbulb.

Here's a sneak peek at video two, which is 'Brainstorming'. We're going to jump right into the design process and explore multiple solutions.

[NSW Government logo.]

[End of transcript]

[Light music plays, screen reads 'STEM Education'.]

Glenn

[High-energy rock music plays.]

Hi, I'm Glenn. Last video, we covered how to define a problem and how to identify our constraints. In this video, we're going on to step 3, the orange cog, brainstorming lots of ideas.

Remember we need to get the teabag to jiggle.

Get your ideas flowing by making lots of quick sketches. It also helps to make a rough mock up and test it out.

[Overlay reads 'Brainstorming Just start! Experiment. Have fun.']

Twirling up and down, you can see I'm changing rotational motion into reciprocating, linear motion.

[Speaker twirls a stick with a teabag tied to it forward and backward over the cup, moving the teabag up and down.]

That may be an idea I could come back to. Let's try and modify this one.

I'm going to borrow a part out of this pen.

[Speaker cuts the end of a pen ink with scissors and inserts it into a circle of cardboard which has a toothpick stuck in it.]

I'm going to snip that off. Put through the cardboard there. OK, can you see where I'm going with this?

If I had something to hold that, that's called a bearing. Let's attach that one [the teabag] onto there [the protruding pen ink tube.]. And, that would work, except it's getting caught around there [the toothpick end]. So, let's do a mod [cuts end off toothpick to be flush with the cardboard].

So this is trial and error. How can I stop this [the string of the teabag] from winding around there [the pen ink tube]? Let's try this.

[Speaker cuts a plastic straw and places it over the pen ink and ties the teabag around the straw. The string no longer gets caught and the teabag jiggles up and down.]

So we're generating reciprocating motion from circular motion. Cool.

If I was looking at option B, being able to use construction materials, that's working very well [a cog with an arm attachment jiggles the tea bag when rotated].

This is a Beyblade launcher that spins these little tops around. When I pull on the rack, it's changing linear motion to circular motion.

What about if I attached a teabag to here? This all seems reliable. On the negative side, it's going to be quite hard for me to make this spin backwards and forwards unless I was using an electric motor and a controller.

[Speaker holds a ruler with a teabag attached to the end and jiggles the teabag into the mug with a see-saw motion.] I can see that a method like this is going to jiggle the teabag. The trick is, how do I get this to move backwards and forwards?

[Bouncing sound effect. Overlay reads 'idea! use a cam']

As this cylinder spins around, it has a lump or a lobe on it. As it comes around onto the linkage [ruler with a teabag attached], boom! There's my motion [tea bag dips into beaker.]. Here I'm changing the direction of motion 90 degrees [Speaker pulls teabag string through cardboard toilet roll to dop teabag.].

It's time to record, to sketch some of these ideas in our folio so that our teacher can see the decisions we've made and to help us remember what ideas we've stepped through.

These are called thumbnails. They're just small sketches showing how some ideas could work. Here's a pendulum swinging. We've got a lever arm moving backwards and forwards. Here we've got a pulley with a crank moving the teabag up and down. These linkages move from high to down low like that. And if I've got a teabag attached to there, you can see how that's going to work.

This one's really interesting. I've seen little mechanisms where the water fills up a container and when the water level reaches way up high, the whole container Spills over like that, the water runs out into a container. As it writes itself back up here to be filled again, if we attached a crank to one end, that crank would be moving like this, backwards and forwards. And if we attached a teabag to it, boom [teabag would be dipped]!.

This is a rack and pinion system. A rack, remember, has lots of teeth in a straight line, and we have teeth in a circle around a gear. This one's called a pinion, rack and pinion.

[Overlay reads 'Brainstorm FInd a power source.']

Now remember, we have to power this machine somehow. Let's brainstorm some ideas. What about if I took some bellows and put some hot liquid in it and it warms the air? As the air cools, it contracts and the bellows would get pulled up and maybe give us the power we need. It's still a concept at this stage. It's untested.

Sketching in 3D is a great way to show concepts. Your drawings might look a little rough at first, but your teacher will love that you've had a go.

Let's brainstorm some more concepts, just for fun. I wonder if we could use the kinetic energy of falling sand into a sand wheel, which collects in a container, to power our device. We could take the motion through a band to a wheel above the cup. That would use a crank maybe to give me the reciprocating motion.

We're back to the bellows. Remember they contract as they cool. Well, if we attached a rack to the bottom that drives a pinion, that drives a camshaft with a cam on it, then that would move a follower.

Can you see an advantage in having a cam with three lobes?

This concept uses a weight to turn a drum.

[Overlay reads 'Maybe ask your teacher about this formula']

Force is measured in newtons and mass in kilograms.

[Overlay reads 'Can you describe the forces in your power system?'.

Acceleration is 10 meters per second per second from gravity. So 20 grams would change to 0. 02 kilograms times 10 giving 0.2 newtons downwards.

Using batteries would fall into the challenge B category. I could join two cells together using a paper clip. That gives me three volts. My three volt motor would need to be geared down. I could use an elastic band to drive a larger wheel.

It's great to have you working along with me. Today we've looked at brainstorming. Next lesson is Design and prototyping. Head over to video 3.

[NSW government logo.]

[End of transcript]

[Light music plays, screen reads 'STEM Education'.]

Glenn

[High-energy rock music plays.]

Hi, welcome back. This is the third in a series of 5 videos where we use the iSTEM design process to solve the Jiggle Challenge. First, the purple cog, design your best solution. Then the green cog, prototype or build your solution.

I need to bring together the best of all my ideas and my experiments into one design drawing. It doesn't need to be a fantastic drawing.

Design drawings are not your final drawings. They're more about helping you to get to the next stage, which is prototyping or making a working model of your design.

As I'm making this design drawing, I'm thinking about the cardboard that I could use. I'm thinking about the drinking container I'm using as a drum to wind the string.

And I'm also thinking about the processes, the holes I'll need to drill or poke, and the parts that I can use. Sometimes beginners over complicate the design by adding on more and more and more things. The trick is to try and boil it down into as simple a design as you can. Just enough to see it work and to prove your concept.

I design with thin, wispy lines. They're like thinking on paper. Only when you're sure about the shape of your design, then you come back and firm or darken them in. Here's the string around the drum, and I'll tie a weight to that, or a mass. Rendering is more than colouring in. It's to help make your objects look 3D, or to show the form, or to help communicate the material that it's made out of. In this case we're looking at cardboard.

I'm making this side a little darker, and inside I'll make darker again. It all helps trick the eye into making this look 3D. Here I'm giving the cup just a hint of colour so that you can see the teabag inside. My design needs to be next to the edge of a table, so that the weight can fall.

Maybe your design will be an improvement and can be sat anywhere on a kitchen bench. The design of your fabulous device probably won't look anything like mine, because it depends on the type of motion that you're choosing for the teabag, how you intend to power your device, and it depends on the materials that you've got.

When you're designing, you won't always draw in 3D. This is called an orthogonal drawing. That means looking directly on to one face at a time. Here's the front view and end view. Sometimes I'll render parts of the orthogonal drawings as well, mainly because they're so untidy that I use a ruler to straighten up the lines.

As I said before, these are not your best drawings. They're a snapshot on where your design thinking is up to and helps you plan for the prototype. If you did show them to anybody, it may be to discuss ideas, to collaborate with other designers, maybe to show the end users where you're up to. Students would certainly be showing these to their teachers and it keeps a record of your thinking.

Here's a fix up. The height of the cup should be the same whether I'm looking from the front view or from the end view. Other orthogonal views could be the other end, it could be from the top, even from the bottom if they were needed. Here, I'm using the colored pencil again just to tidy up my lines and to help it lift off the page and to really show that outline, I'm using a darker line outside of that light line.

The drum also gets its own outline to help it stand out from the cardboard that's behind it. So here's my finished drawing, including a detailed drawing that shows my thinking on how I'm planning to make the crank, including the pin.

[Speaker demonstrates prototype made from cardboard and a drinking chocolate tin.]

So for this mock up, I've put a hole in two ends of the drinking can, and I've used a skewer with a straw on there to stop this from rubbing against the cardboard. That seems to work really well. From this angle.

On the end of the pin, I glued a round disc to hold the teabag. Here's an issue, I can't move the cup far enough across to get it under the teabag. So here's my fix up. I'm marking where I'll need to cut and fold, but always check with an adult and have supervision before using sharp knives.

I'm getting really close to finishing my prototype. I can't wait to test it. The last thing is to attach a weight to the string, and I'm going to wind it up 15 times. I'm aiming for a maximum of 15 jiggles.

How do you think my prototype's going to go when I test it? Join me in video 4, Evaluate and Iterate, which means to test and improve.

There's a clue. Thanks for joining me. See you soon.

[NSW government logo.]

[End of transcript]

[Light music plays, screen reads 'STEM Education'.]

[High energy rock music plays]

Glenn

In the last video we covered prototyping. We're moving on to the blue cog, Evaluate.

Let's evaluate how well the device works. Attach a weight, wind it up, ready, 3, 2, 1, go!

[Error sound effect.]

Oh, the teabag got caught around the crank. Let's try slowing the drum down by resting my thumb against it.

Now the teabag's moving much smoother there, but how can we slow it down?

Well, I'm experimenting with wrapping the string around the straw, around the shaft. Let's give it a try.

First I've cut the string. I've shortened it because now that it's a smaller spool, I'm using far less string. I don't want the weight to hit the floor. Let's see how we go.

[Error sound effect.]

Hmm, it looks like something's slowing it up.

It seems to be the string getting caught in between the cardboard right in there. So let me try and wrap it around again, and we'll test. Much better, but it's not really, it's not enough tension or force to be able to pull it from that straw. What we need is in between those sizes. Let's see, maybe a cork is in between the big drum and the straw size, so we could cut that down and use it perhaps.

Be very careful if you're using sharp knives, always check with an adult. And, never hold anything in your hand when you're trying to put a hole in it.

Plan B, I'm using a piece of cardboard here and I think I actually wrapped it around a screwdriver, so that it was the same size as the straw. So that is my spool that I'm going to wrap the string around.

To stop it coming off each side, I'm going to stick a little piece of cardboard. There we go, all ready to assemble. Let's take off the drum and pop my spool on there.

Let's put the drum back in. Really tricky to line up that hole there, so I found it easier to pop the lid off, line it up with the skewer, our shaft. And then pop that back on. All right. I think we're getting close for another test. So now I'm wrapping the string around the spool.

Here we go. 3, 2, 1... Oh yes, that's much better. Much more power. Could you spot the problem? The crank isn't spinning and the teabag's staying still. So I'm going to need to connect the spool to the shaft which is connected to the crank.

A little piece of tape here will get me out of trouble. With this sort of prototyping, remember, the quicker you can mock something up and learn the lessons, the better.

So here we go, we're wrapping the string around the spool again, and I'm hoping for a better result.

Much smoother.

Now it's time for the next iteration, or the next improved version. I'm really excited about redesigning, given that I've learnt so much already.

[Resketching the design.]

I've left off the big drum, we only need the small spool. Let me walk you through the design. Let's start with the main shaft. I've made it stronger by going up to a diameter 4 bamboo.

We'll position the spool on that. And for the crank, it doesn't need to be right angle bends. It can be a bend, it can be shaped like that [a more obtuse angle bend]. This one I found in the garden sprinkler. And I bent it just on a little flame. Just heated it really gently, didn't burn it. On to there. So that worked really well.

But to hold the teabag, I've got this old milk bottle, and cut out a little bit of plastic. I was really lucky to find a screw that would fit into the end. So let's assemble that. I do have the option of using a crank at both ends for two teabags at once, or I could make it a little knob for twisting, twirling the string up quickly.

I did start to think about some sizes for my final design.

In this iteration, I've redesigned how I hang or attach the teabag. Different crank, and have a look at the paper clip, does two things. It stops the string from rubbing on the cardboard, but it also extends the string out so that the weight dangling over the table doesn't hit the edge of the table.

3, 2, 1. Oh, it's working really well, but way too fast. I need to slow the motion down, using a governor of some sort.

Using air resistance, this paper's easy to spin slow, hard to spin fast. Let's give it a try and see how it looks. 3, 2, 1 Awesome! That's getting close to a really good quality jiggle right there.

Each revolution did seem to speed up and slow down. 180 degrees, the teabag's being lifted, and then the other 180, it's falling.

My next step would be to investigate counterweights on a crankshaft. There's a clue for you. I'm not going to solve this for you. It's all over to you. Did you notice we haven't yet had a test where we've put the teabag in an actual liquid?

You'll find that when you do, there'll be a whole new set of challenges to solve, and more fun to be had.

I'm Glenn, join me on video 5, the last video, where we'll be looking at communicating your idea. Thanks, bye.

[NSW government logo.]

[End of transcript]

[Light music plays, screen reads 'STEM Education'.]

Glenn

[High-energy rock music plays.]

Hi, welcome to Video 5, Communicating your design through drawing. This is the final in a series of 5 videos. In the last video we covered Evaluate and Iterate.

The drawing I'm working on here is a pictorial, or 3D, type image. I'm using an isometric tool to help set out the basic 3D forms. Then I'll add the details, followed by some colour or rendering.

[Jazzy music plays while the speaker draws a detailed technical drawing in fast-motion.]

[Overlays read:

• 'Quick sketches work best to imagine new possibilities'
• 'Sketching in isometric is a great way to begin drawing in 3D'
• 'Maybe the side could tilt out to suspend the string?'
• 'Combining two functions into one part is a good design principle'
• 'With practice, many concepts could be communicated in a very short time'
• 'Coloured pencils work just as well as these art markers'
• 'Rendered, isometric sketch']

[Visual displays the finished technical drawing and then changes to a computer-generated image.]

This image has been drawn with the help of a computer. It's called Computer Aided Design, or CAD. CAD drawings have lots of advantages, like, one, checking the parts actually fit together, two, being able to make changes to drawing very, very easily, three, it's super easy to communicate and work in teams.

Imagine, while you slept, someone on the other side of the globe could continue working on a project. In industry, this is happening right now all around the globe.

[Speaker walks through the parts of the design in a CAD program.]

Here we're stepping through the latest iteration. Notice the fan or speed governor is now on the inside and I'm driving that using those two brass pulleys with a band.

I'm placing a cap on top so that I can position a little release or on button in a fairly obvious position. A good design should communicate, how to operate the product. And you can also see a little bit of red detail there where you hang the teabag from.

I'd like to show you some of the other features that are typical of many of the CAD programs. For instance, here we're working in 3D, we're working in the design feature. Let's go back to the home page and run through some of the options.

Here's the design, but I could also choose to render from specifying materials and appearances. I can animate or have the parts moving around. Simulation allows us to easily see where the forces or stress is located inside the components.

Manufacture is for C.N.C. milling [Computer Numerically Controlled], or if I wanted to output STL files to a 3D printer. And drawing is a major feature. I can go straight from the design and output 2D drawings.

Now that I've got my page all set up, I'm choosing the base or the most important view. The scale's too small. Let's go 1 to 1. That looks a little too large, so I think we'll go scale 1 to 2.

Now that I've set that, I simply click on the base view and drag across the page and it generates for me the end view. And if I drag upwards, I get a top view.

If I drag on a 45 degree angle, it generates an isometric view. But it's a little too large sitting there, so I'm going to select the isometric. And for it, choose a smaller scale.

Good, so there's all my line drawings done in about 10 seconds. That's a real advantage with CAD.

I'm going to show you, if I cut through one of the drawings, and then drag upwards, that's my sectional drawing.

Here's something to keep in mind with CAD drawings. They look so good and so finished, it's hard to remember that this drawing is really not much more than a concept, and isn't yet fully resolved.

That's something to keep in mind when you're communicating using CAD drawings.

Here's the orthogonal views, the plans. Now I just need to go and print them out. With CAD, if I change my mind, it's really easy to edit. Here I'm adjusting the thickness of the base. And the good thing is that when I update that drawing and go back to my plans, it will automatically update the 2D drawings.

In this video we've looked at ways that you can communicate your designs through drawing. Drawing helps to develop creative thinking, enables working in teams. Sketches keep a record of your design thinking, so that you could jump back to a previous idea you've had and consider it further. Orthogonal drawings, plans, communicate how a product should be manufactured.

We need young people to step up and learn these skills. There's no better way than just starting. Fail, then figure it out. Be bold.

Thanks for watching. Now go engineer something.

[NSW government logo.]

[End of transcript]