STEM: Walking water with Guy at Sunnybank Hills Library - video transcript

This page is a transcript of the 'STEM: Walking water with Guy at Sunnybank Hills Library' video on Brisbane City Council's YouTube channel. The video is 11 minutes and 16 seconds long.

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>> GUY: Hello, welcome to Brisbane City Council libraries. My name is Guy and I’m from Sunnybank Hills library. Welcome to our library lab at home! Library lab is a fun way to learn about science and engineering. Today we are going to look at walking water. So, we have used items that you can find around your home, so that you can try this yourself with the help of an adult.

What you’ll need are: Seven clear plastic cups, Six folded sheets of paper hand towel, Food colouring - red, blue and yellow colours, and a jug of water.

As you can see, this is what we've already made. This has been on action now for the last couple days, and you can see all the different colours that we have. You’ve got your reds on the outside, then you're blue and yellow on the inside there. The other cups, these three, they originally started as empty. But, since then the colours in the water have travelled. Two outside ones to the inside one. Same for these two into there. And the same for these two into here. As you see there’s is different colours that it's made.

We originally started with red, blue, yellow, and another red, but as the colours have moved, somewhat mysteriously, then they’ve mixed, as you can see on the paper at the top here. Different colours and moving water. Two different things that we are going to be experimenting today with our library lab.

Okay, now the first thing that you have to do is you have to fold your sheet paper hand towel. So, fold it in half, fold it again, and then fold it in half again, like so. So, make sure it's nice and well folded, that’s good. Now what you need to do then, is just to test and make sure that your paper towel can reach as close as it can to the bottom, hopefully touching it like so. So, we’ll just test that out, push it down, that's pretty good. If your paper hand towel is stuck out too high, then the water wouldn't be able to walk over the bridge to the other side. Okay, so that's good, so we will take the paper hand towel out now, and let’s fill your cups with colour.

So, we’ll need four cups, one, two three four. Now the next thing you have to do is fill your cups with water. So, fill it about halfway. Try to make them all equal. Good, so now you’ve got your four cups with water.

The next thing that we have to do is to mix our food colouring into the cups of water. So, we’ll start with red, you will need about five or six drops. Be very careful because food colouring can stain your fingers, so you might end up with red, yellow, or blue fingers after this experiment. It's no harm. Oh, look at that! Wow, little explosions of colour. One, two, three, four, five, I’ll do six.

Then we’ll do two cup of red. One, two, three, four, five, six. Isn’t that beautiful! Look at it. Let’s see if we can mix that with a little bit of a shake. Ah yeah, that works. You might want to use a spoon for this. Actually, it’s just mixing itself quite well, if you just leave it for a bit, so that’s fine. Okay, let’s mix the other two colours now. One, two, three, four, Oh, this is quite dark. I might leave it at four and just see how that goes, I think the blue’s a bit stronger than the red. I’ll leave that for a little bit and see if it mixes in.

Okay, and our last colour, yellow. I might need a bit more yellow than the other colours I'm thinking, let’s see. One, two, three, four, five, six, seven, eight, nine, give it a little bit of extra strength because I think the yellow is a bit weaker as far as strength goes to the other colours. Very nice.

Now that we've got our four cups of coloured water, let's set up the experiment. So, we’ve our three extra cups, so spread out the other two. Put cups in between, nice and close together. Okay, we need to add the paper towel sheet, water walking bridge into each cup. So, we’ll add that in like so, sits in there nice. And as you’ll notice already the colour in the cup with the water in it is already starting to travel up over the bridge this is a process that's called capillary action.

We all have capillaries inside our body and that’s what our blood flows through, and this similar to that - small little tubes or channels in the paper that makes the water absorb up against gravity and then down the other side. Once it goes up against gravity and starts going down the other side and gravity is working with the water that’s been absorbed to pull it down and it acts a bit like a wicking type or siphoning type action.

Okay, now we need another one in here, good. Look at the blue travel up, it’s quite strong the blue. I’m looking at the red thinking it might need a bit more colour in it. I can always add a bit more in, there’s no problem with that, you can always modify the experiment, just to make it work a bit better. That’s good, the yellow is really absorbing through there. And now our last sheet. It’s looking good. Try to make sure the paper stays down as low in the cup as it can, because if the water level goes below the paper then it won’t absorb. Okay, it’s been just over an hour now and we could see how all the colours have joined together.

Okay, now as you can see in the first two cups the red and the yellow, the water has walked over the bridge, and down again, and joined together the two colours in the empty middle cup, and you can see there's quite a bit of water in this one and the rest of them. The colours have joined and have formed orange, wow! So now you know that red and yellow make orange. Okay, on to the next two, the blue and the yellow. So, again they have travelled over and combined together to make a lovely looking green colour in the middle empty cup. Okay, onto the last two, the red and the blue, they have joined together in the empty cup to form quite a nice purple. Here is the finished result which is a beautiful rainbow of colours.

I hope you’ve had fun watching the colour water walkover the paper bridge and creating all these different colours. Thanks for joining us!

Last updated: 2 July 2021
Topics: library