Science at the Library: Structural shapes

Hello everyone, my name is Mikayla and I work in the Public Programs team here at the National Library. 

The National Library is located in Canberra on the beautiful lands of the Ngunnawal and Ngambri People. 

The National Library pays our respects to their elders past and present, and through them to all Aboriginal Australian and Torres Strait Islanders. 

At the Library we work in an impressive building in the Canberra landscape. 

Close by is the Commonwealth Bridge, the wonderful building that is the National Library is based on the ancient Parthenon in Greece. The Parthenon was an ancient Greek temple, parts of which are still standing today. The Parthenon was built over 2000 years ago, and while it is no longer the majestic temple of its origins, some of its formations remain. 

Well-built structures stand the test of time. Structures like the National Library and the Commonwealth Bridge rely on a collection of engineering processes just like the library's collection relies on building a catalogue process to keep everything in order. 

Structures are about order and at the base of some of the world's largest structures are geometric shapes used in repetition. If you look at the library from the outside, you'll see the columns are repeated. This gives strength and shape to the building, but if you look at scaffolding around construction sites, you'll see rectangles repeated, providing safety to the workers.  

In the fun experiment you’ll be shown today you'll see triangles repeated to create the structure of strength. 

To build a bridge like the Commonwealth Bridge over Lake Burley Griffin required many different geometric shapes in its construction. The main structure is a web of boxes. The central legs of the bridge are octagons on top of cylinders, shapes held in place by other shapes. 

With the help of our friends at Fizzics Education we've got a fun experiment that you can try yourself. 

This school holidays we're bringing you building for fun. Did you ever wonder how buildings like the library or bridges like the Commonwealth Bridge or a bridge near your place stay so strong for so many years? Or think of the pyramids of Egypt or the skyscrapers of New York City or the amazing buildings in Dubai. 

Geometric shapes are found everywhere in construction. In our libraries, the books are combinations of squares and rectangles while the shelves are the structures strong enough to hold hundreds of books. In fact, the National Library holds over 3,000,000 books of all shapes and sizes, right down to one as tiny as your fingernail. 

Remember, before you do any kind of experiment, always ask for permission first and have an adult nearby that you trust nearby to help you out. 

We hope you enjoy learning with our friends from Fizzics Education.  

For the experiment you can use jubes, like our presenter, or why not try some marshmallows, see how long or how high you can go with your structure. If you can't use lollies then try with some play-doh. You might even try to build some structure of your own using some other geometric shape. 

So let's get building. 

You know what? You don't have to have really strong materials to hold a lot of weight, now of course concrete is handy. It is very good at making some super strong bridges and some super high towers, but here's the thing, your kitchen materials can make things be held up if you set them up in the right way. So that's the plan. We're going to set up this structure multiple times and we’re going to use this to hold this book and you know what I reckon at home you just might be able to hold just more than just one book. 

Tell you what, let's go check out how we do this. So, what we need are some toothpicks, so any regular toothpicks will do fine, and this is the best bit, lollies. The ones that we got, well we're using jubes, they're actually a little bit hard and they've got a little bit of structure but also, they're also well frankly, tasty. So, let's let's do this while I talk with my mouth full. 

So, what we need to do, is that we need to make this tetrahedral shape. This four-sided shape which is made out of triangles and it's really not too bad when you start looking at how to put this together so I'm gonna put these off to one side and we'll start building up one at a time as we go along. So, first job is we need to well push our toothpick into your jube and let's not hurt ourselves here. Just take it nice and gentle. Just be aware where that toothpick is in relation to your well fingers, but we just need to make a simple triangle. 

So how are you going with that so far? Follow along. Push on in, now, of course, if we want to be perfect, we can make it equilateral so the same angle on each spot, but it doesn't have to be absolutely perfect now, just yeah, it's OK. Now I'm going to push a toothpick here and now another toothpick up here and finally, another toothpick here. We're kind of making a little pyramid. There we go and we're just going to do a capstone. Just put that there and there and there. Now here's the bit where we're going to need to be able to set this up so it can actually hold the book. Clearly the point is no good. We need kind of like a flat surface, so we're gonna have to keep repeating this shape over and over and over to make a long girder sort of shape. That's the plan. 

 So, let's keep on going. Let's put another toothpick out this way again, it's nice if we get the angles perfect. It's OK if you don't get it spot-on so, let's just keep on going. We'll keep on building this out over and over. And we'll see how we go with building this, one over one, point, point, point, push, so it's almost like a diamond shape, see that almost like a diamond shape, we keep on going, let's put out another couple of toothpicks and here we go, here we go yep there we go and now we put another one in, push! 

 Now some people at home may have people in their family who work at building things and have known that building things with triangles makes the structures really strong and this is something that’s been known by people for a very very long time. Because triangles distribute force, they're really, really good at it, and in our case, we're going to need to distribute the force of our well honestly, quite heavy book, so we’ll keep on going and we'll get there very very soon. Here we go, push and push and well I nearly missed my thing there. Looks a bit wonky. You better unwonky it. Unwonky that might be a word, or is it a word?  I don't know. We are working with the National Library, so I'm hoping that you guys can look up in a dictionary, go and find out is unwonky a word, yes, or no? I've got a funny feeling, it's not.   

Anyway, we'll keep on going. Here we go pushing, pushing. Oh, we’re nearly there. This really is a repeating shape over and over and over and over and over and over and over again so that we end up with a bit of a flat surface to work from so in we go get that there ready to go. Again, don't stress if it’s not spot on perfect. I mean I must say in this video I'm sort of rushing through a little bit quickly just so that we can get it done and we can get there, but you might take a bit more time and make it really, really nice. 

I reckon I'm getting very close. Oh, it's a bit wonky up there that's OK, we can fix that up soon. Sometimes people get paralyzed by getting things absolutely perfect. You know what done is better than perfect and then fixing it later is even better.  

But just getting your first prototype is part of engineering design, checking things, seeing if it works, then fixing it later and making it better. But if you never check things and you always want it to be absolutely perfect, maybe you might not get there cos you're spending too much time making it perfect. In this case, you’ve gotta spend some time trying a prototype, testing it and then seeing if we can make it better. 

All right, so that is a bit of a structure, so here's the thing. I just to speed it up a little bit I've also made a second one. We've got two. Oh look, there's one that's popped out there. Fix that one up there. 

So, what do you reckon? Can this hold my book? Let's get it, let's put it on and we are good. It's done it, YES. 

Now here's the thing. I reckon that you can make a structure like this just as effectively if actually a little bit stronger. My challenge to you is what if you try to get your book higher and then higher and then higher. See how high you can go with your tetrahedral shapes that connect together to make a bridge, and in this case it's all about triangles and moving force around the place and the best bit about this is that, well, you get to eat it, at the end.