- Are you feeling curious?

- [All] Yeah.

- I'm so glad.

Today on Curious Crew.

Oh, great suspension right there.

What forces caused some things to stay afloat?

- Oh, mine's floating.

- Oh, oh my gosh, while others sink.

Whoa, what's going on there with the hot one?

Could it be magic?

Abracadabra.

Or molecules?

If we are molecules, we'd be moving.

Don't drift away.

The crew is about to submerge itself into the science of-- - Surface tension.

- Surface tension.

How about that?

- [Narrator] Support for a Curious Crew is provided by MSU Federal Credit Union offering a variety of accounts for children and teens of all ages while teaching lifelong saving habits.

More information is available at ufcu.org by the Consumers Energy Foundation dedicated to ensuring Michigan residents have access to world-class educational resources.

More information is available at consumersenergy.com/foundation, consumers Energy Foundation supporting education and building sustainable communities in Michigan's hometowns.

And viewers like you.

Thank you.

(upbeat music) - Hi, I'm Rob Stevenson, and this is-- - [All] Curious Crew.

- Welcome to the show, everybody.

We always like to start every episode with a couple of discrepant events because discrepant events stimulate-- - [All] Curiosity.

- That's exactly right.

And I've got some fun ones for you today.

First of all, I have to point out I have three glasses of water right in front of you, in fact.

Now, the one thing that you need to be aware of this first glass over here is really cold water.

The second one is really hot water and the third one is just room temperature.

You're also gonna notice in front of the glasses I have a little paper towel with three metal screens on them.

Now, in fact, I took scissors and I took an old window screen but I cut three little pieces of metal.

Emmanuel, I'd like you to make a prediction for me.

I'm gonna put one of those screens in each glass and I'd like you to predict what you think is gonna happen.

Okay, so let's think about what will happen if I place a screen in the cold water first.

- I think it's gonna float.

- He says it's gonna float.

Let's try it delicately.

It did.

Ooh, that was a good prediction.

Okay, how about the hot water?

- I think it's going to sink.

- He thinks it's going to sink.

And I saw a head nod from somebody over there.

Let's take a look.

Ooh interesting.

Okay, and how about the room temperature one?

- I think that one is going to float.

- You think this one's going to float.

Okay, how about that?

I'd like to try something for just one second.

I'm going to add a little solution here to this room temperature cup and just see what happens.

Oh Uh-oh.

Sorry about that.

Okay, that one went down and I have a nice little stream of solution moving down as well.

Very interesting there.

Okay, I'd like to direct your attention now to this.

Ishan, could you describe for me what I have here?

- Well, it looks like blue water.

- It actually is blue water.

Now in fact, what I'm going to do is kind of surprising at least to me, but I'm going to do it over top of this.

Okay?

Oh dear.

Oh dear.

Oh my goodness.

Okay, so we've got ourselves a leaky bottle.

Now notice, open, close.

Open close, open, close.

I'm having a little too much fun with that now.

In fact, I'm noticing something here as well.

Look at the middle glass now.

We've got a sinker going on there.

So this is kind of strange.

It started off floating.

It ended up sinking.

This one's still floating, and that one sank after we put some solution in there.

Okay, we've got some interesting discrepant events here.

I'm gonna invite three of you to do a little scientific modeling to see if you can explain these phenomena by the end of the show.

You can use information throughout the show to revise your thinking.

So who wants to engage in a little modeling moment?

Who wants to try this?

Okay, Kean, Ilaria, Callan.

You three are gonna do this.

And now I have another question.

Does anyone have a prediction?

What we're gonna be investigating today?

What do you think Genesis?

Probably something to do with water.

That's a very good prediction.

Specifically surface tension.

Stick around.

We're headed into uncharted waters.

(upbeat music) - So let's figure this out.

What did you notice Ilaria?

- It really surprised me when the bottle started leaking.

I didn't see any holes in it.

- I know, right?

How come the water didn't leak before Dr.

Rob touched the cap?

- Yeah, I was wondering why the screens floated on the cold water, but not the others.

- It looked like soap that Dr.

Rob put in the water.

It must have affected it somehow.

- Have you ever seen a water droplet on a leaf or sitting on wax paper?

The water droplet stays together with a skin like surface.

This is a great example of surface tension and water.

The molecules in the droplet have strong attractions to each other.

Try filling an eyedropper with water and drop several droplets on wax paper.

Notice how the individual drops hold their shape.

You'll even be able to use a straw and gently blow them around on the surface.

Those molecules have great surface tension.

So if we're gonna investigate surface tension I'm going to give you the classic experiment.

I'm gonna challenge you to see if you can take a paperclip and rest it on top of the water so it appears to be floating.

How well do you think this is gonna work, Ali?

- I don't think it's gonna float.

- Let's try it.

You each have a cup, you each have a paperclip.

Go ahead, try it out.

See if you can get it to balance it in there.

Now the trick, of course is you have to try to keep it really level.

Oh, mine totally went down.

- [Ali] Oh, mine's floating.

- Oh, oh, oh my gosh.

You're my hero.

You're my hero.

Ali, I'm so impressed.

Oh my gosh.

Okay, so don't feel bad.

Mine went down.

Okay, for those of us that had a little epic fail grab a little tissue paper and drop this in first.

The tissue paper will start to wick a little bit some of the color down into glass, but that's totally fine.

Now take your paperclip and place it on top.

Ali, I can't believe you got that in the first try.

Okay, now we've got it in there level.

Once we've got it sitting on top of the tissue paper take this little wooden skewer and force the tissue paper down.

Do it gently around the edges so it doesn't happen too fast.

And once you get that tissue paper out of the way you will end up with a floating paper clip.

Most people are not like Ali and can get it on their first attempt.

There is another way to do that that's even easier with a different object.

I want to point out something right on the end of my pointer right there.

That is a little spring.

Julia, where do you think this is from?

- I think that's from a ballpoint pen.

- You are totally right.

For some reason it is easier to place this in the water than the paper clip.

So now we've got these floating on top.

And how is that happening?

This is all about surface tension, right?

Okay, link arms for a second.

We're gonna pretend that we are water molecules along the top of the water.

Now, we don't have any water molecules above us but we have water molecules below us.

And guess what?

They're pulling us down too.

So we're being pulled down and pulled side to side which creates this wonderful little skin like layer right across the top of our heads.

Now you can imagine that paperclip or that spring resting on our heads isn't that strange?

Surface tension.

Of course, we can also disrupt surface tension.

I won't disrupt yours.

I will disrupt mine.

I've got a little solution here.

What do you think this is Callen?

- I think it's soap.

- You are so right.

It is soap.

I'm gonna saturate this swab and put some soap inside the glass.

Notice it's like, oh, get away from me.

Oh, they both went down.

That completely disrupted.

Let's link back up.

Think about those water molecules.

And suddenly the soap it separates the bonds between the hydrogen particles and we suddenly lose that surface tension.

Amazing, these are some investigations you can try at home.

Some classic ones.

Try to challenge your family, see if they can do it as well as Ali can.

Imagine, we had microscope eyes and could see the molecules to understand how the water could support the pen, spring and paperclip.

Water molecules have a strong attraction to other water molecules around them.

The ones on the surface though only have particles below and beside them, so their side to side bonds are stronger.

The surface particles are also pulled down.

As a result, they form a skin like layer that could support the spring and the clip.

Amazing.

So we've seen how surface tension can support things from up above, but now we're gonna look at things in another way almost to defy gravity.

You'll see what I mean.

First of all, Julia, take a look at this bottle and what do you notice about it?

- It seems like you put a hole in it Dr.

Rob.

- You are totally right.

I actually put the cap on a drill press and I cut a 12 and a half millimeter hole or equivalent to about a half inch.

I now have some colored water inside.

Julia, I'm gonna do something that might not be a great idea but what do you think's gonna happen if I turn this over?

- I think all of the water's going to come out on the table.

- Okay, okay.

I really hope I don't make too big a mess.

Here we go.

I'm gonna try to do it right over this plate.

Okay, here we go.

Oh, there it is.

There it is.

Okay, my magic bottle, which is defying gravity.

Now I don't want to squeeze and I don't want to move and I'm gonna attempt to turn it back over.

Okay, that's kind of cool.

I also want to direct your attention over here.

First of all, Ken, do you know what this is right there?

- That looks like gauze.

- It is gauze.

Okay, we're gonna place some gauze over top of this bottle and put a little rubber band around it.

And Ishan, you're gonna help me out with this one.

I'm going to flip this over.

Now, clearly this gauze weave has lots and lots of little holes in it, and I'm gonna ask you to take a toothpick and push it through.

And what I'd like to know is what do you think is going to happen?

I'm gonna turn this over first.

See if I can get some surface tension working.

Oh yeah.

Okay, Ishan, what do you think is going to happen?

- I think that all the water's gonna come out.

- Okay, go ahead.

Pierce one of those toothpicks right through.

- [Ishan] Oh.

- Oh yeah.

Grab another one.

That was kind of surprising.

Notice it.

Whoa okay, one more.

Do one more.

Is it amazing you would think that the water would come rushing out as he's perforating right through that surface tension.

Let's think about what's going on in both of these cases.

So if we know those water molecules are clinging together and resisting being separated apart amazingly, even though we've got gravity and air pressure at play here it's not going to wick out.

And surprisingly, when you put the toothpick inside those water molecules attract to the toothpick.

The toothpick goes back and then they attract to each other.

Amazing.

So you can see surface tension can be quite impressive.

One of the best examples of seeing surface tension in action is with water striders.

Those insects are designed to walk on the skin like layer of water.

The insects have very long legs that can distribute their weight over a big surface area.

And even though gravity pulls them down the tension among the water molecules is greater.

So they stay on top and can walk around if ever a wave or to splash over it the tiny hairs on its body trap air keeping them afloat and its hydrophobic legs shed the water so it can climb right back on the surface again.

Imagine if we could do that.

So have you been having fun investigating surface tension today?

- [All] Yeah.

- I'm so glad.

Now I have a question.

Have you ever seen an insect on water?

Raise your hand if you've ever seen an insect walking on water.

That is amazing, isn't it?

I've got a challenge for you today.

You're going to be making your own surface strider out of wire.

Okay?

You ready to get started?

- [All] Yeah.

- All right, let's do it.

- We could do three different lengths.

We could do a long one, a medium, and a really small one just to see how length affects, you know the surface tension on the water.

Is that a good idea?

- Yeah.

- We should start cutting our wire first.

- The materials we used were 28 gauge wire, a popsicle stick and a bowl of water.

Where are you going for in like length wise?

I'm gonna do a long one.

It's supposed to stride on the surface.

You're supposed to connect the wire and make it flat and even and level so that when you put it on top of the bowl of water it balances.

- Okay, I think I have my strider.

- No, that was so close.

- We did three different lengths to test the different impacts, but we realize that you have to make sure all the legs are level or else it won't float.

- Guys, I think this might work.

I'm gonna try it.

Oh, okay, okay.

- Sometimes it would like float for like one second, then it would sink.

- Make sure you have the legs even like set it on the.

- Okay, it fell again.

- My advice to the kids that wanna try this experiment at home is make sure the legs are straight and flat when you put them on top of the water and that they're in line with each other.

- I can't tell if the issue is the design or me putting it in the water.

I think it might be both.

- I would say not make your surface strider too long.

'Cause then it would be a little bit heavy so it won't float.

- Why is untwisting?

- [Ishan] Hey I got it.

- So hard at work with the surface striders.

I was watching from afar and I saw some of you having some success.

I also saw some taking nose dives.

So what are some noticings that you've made?

- I've noticed that it's hard to keep, get the legs level.

- Yeah, so they will all contact the water at the same time.

That's a really important part of this investigation.

Good, Ali what's something else that you noticed?

- The smaller the bug is the easier time you have getting it to float.

But also the longer it is the more of an impact it has on the water.

You can really see the water like bending around the weight of the leg.

Oh that's fantastic.

So you can almost visualize that surface tension interacting with the leg, great noticing.

Julia, what else?

- For the surface riders that use more wire they wouldn't stay on top of the water for as long so they might stay on the surface of the water for a little bit, but then they would sink shortly after.

- And I saw a lot of you making some adjustments after you made a surface strider, raise your hand if you did that.

I saw people cutting legs shorter.

'Cause like, ah, nope.

I gotta rebend it again so we can get it just right.

So the crew used 28 gauge wire.

You may or may not have that at home but if not, no worries.

You can always grab a couple of twist ties from some loaves of bread.

Remove the covering and you've got the perfect wire to make your own surface striders.

Have you ever tried to combine oil and water?

It's interesting to observe that the two liquids don't mix.

Just like the liquids in a lava lamp.

Lava lamps are often made with water or mineral oil and then a colored liquid wax is added.

They're often compounds added to the wax to increase its density.

The two substances do not mix as the similar particles stay together.

This kind of surface tension between different substances is called interface tension.

Now that's some terrific tension.

So we've already seen one way to disrupt surface tension today, and that's with soap.

We're gonna explore one other way.

And Emmanuel notice here we've got a cold glass of water and a hot glass of water.

But I also have a couple of cotton balls.

I'd like you to predict for me, what do you think's gonna happen when I put these cotton balls in the glasses?

- I think they're going to float and I think that the hot one is going to sink first.

- Okay, hot water's going to sink first.

Let's drop these in.

Boynk, boynk.

Oh, great suspension right there.

Whoa, what's going on there with the hot one?

Goodbye cotton ball.

Now that happened awfully fast much faster than I even expected.

I'm gonna direct your attention right over here.

I've got another experiment.

This is an ordinary glass of colored water.

I'm going to place this plate.

Oh my goodness, this is not a good idea.

Okay, and we've got it turned over ever so carefully.

I've lost a little bit of water, but that's totally fine.

Ilaria, do you think it's possible for me to slide a quarter in between the plate and the rim of this glass?

- I mean, not unless you're a magician.

- Let's see, Abracadabra.

Okay, I'm going to very carefully tip and push.

Oh my, oh my.

It's there.

Now we lost a little bit of water, but not the whole glass.

Do you think we can do it again?

Yeah.

- Okay.

She's feeling a little more confident now.

You did it once.

Maybe you are a magician Dr.

Rob.

Okay, I'm gonna place this in right over here.

Try to separate it equally apart.

Oh my gosh.

I think we need to go for a third one.

I think we have to go for a third one.

So this entire glass is resting on quarters.

No way.

And we still have all that water inside and yet there's a gap down at the bottom.

Genesis, do you think we could get another level of quarters in there?

- I mean honestly, with the way things are going, yeah.

- You have such confidence in me.

I'm a little nervous.

Okay, I'm gonna dry some of this just so we can see if we end up having this awful explosion of water at least we'll know.

Alright, here we go.

Second level coming in.

Oh, I got it in.

I got it in.

Okay, I got it in.

Let's try this side.

I gotta turn that a little more slowly so I don't knock the glass over.

That one went in really fast.

And one more.

Okay.

Will we keep water in the glass?

Now we lost some but I still have quite a bit of water inside that glass.

Think about this, my friends.

We have just created a three millimeter gap in between these quarters and the water's not coming out and we can attribute that to what?

Perhaps?

- Surface tension.

- Surface tension.

How about that?

So we have seen there is another way to disrupt surface tension.

That's with heat.

We get those molecules moving faster.

Think about this.

We're gonna link arms for just one second.

We are molecules all along the top and all of a sudden if we are molecules, we'd be moving right?

Moving back and forth.

Now, if we are happen to be hot molecules we're moving way faster which means our bonds start to weaken and break.

And in fact, the cotton ball clearly thinks look at that one.

It is still floating like mad.

We've got some great surface tension over there.

These are some impressive examples of surface tension.

And in fact, you could take that to the bank.

As impressive as surface tension and water is, it isn't indestructible.

We've seen two quick methods to disrupt surface tension.

Soap is really affected because the soap molecules on one end attract water while the other end repels it and attracts grease.

The presence of soap weakens the hydrogen bonds by spreading the water particles apart.

Another way to disrupt the surface tension of the water is to heat it up.

As the particles move faster, their bonds get weaker.

And that's why so many items get washed with hot soapy water.

Now that will really disrupt the surface tension.

(upbeat music) - Are you curious about careers in science?

Hi, I'm Janellyn, and today I'm with Dr. Evangelyn Alocilja.

Dr. Alocilja, tell me where we are and what you do.

- We are in the Nano-BioSensors lab at Michigan State University.

We do research on nano biosensors.

Nano biosensors are devices that use biological materials and nanotechnology to detect diseases especially for humans.

Animal health, environmental sciences.

So the magnetic nanoparticles are floating around trying to grab the bacteria or virus from the sample.

We put them in a magnet.

They are now moved to the magnetic side.

- Whoa.

How did you get into career like this?

- With my background in chemistry, biology, and engineering I could contribute to the research of biosensor because it is a lifesaving technology.

- Evangelyn Alocilja showed me how something this small can have a huge impact on our lives.

Explore your possibilities.

And now back to curious crew.

- So we know that surface tension can hold up the screen just like the paperclip or the spring.

- Right, remember the soap caused them to sink the bonds between the molecules were messed up.

- That must happen to the screen too.

The temperature must have affected the bonds.

- That makes sense.

Molecules move faster at higher temperatures.

So maybe the bonds were just messed up.

- What about the leaky bottle?

- We've seen how strong surface tension is like in the magic bottle.

Water didn't come out of either of them and the holes in the leaky bottle were much smaller.

- So have we had fun investigating surface tension today?

- [All] Yeah.

- So glad.

Well, I'm sure you might have had a sinking feeling thinking about trying to solve these problems at the beginning but I know you're a very cohesive crew too.

So what have we figured out about this leaky bottle Callen?

- We decided that you poked pinholes in the bottle and with the cap on the water wouldn't come out.

- Right, the attraction between the water molecules is so strong that click a skin layer clogging the holes.

- Oh, you guys are so clever.

Okay, so first of all, I have to tell you yes, in fact I used a little push pin.

You caught me.

Now there's holes all around there because we could see the results.

Oh no.

What about the startling screens Kyan?

- Well we know that the screen floated well in the glass of cold water because the surface tension.

- We think the particles in the glass of hot water were too hot.

Therefore they had a bad surface tension and the screen sunk.

- And the soap you added messed up the surface tension.

That's why the screen sank.

- Okay, so clearly I've got soap here.

It's not just a solution.

You're correct.

It was soap.

So we can see amazingly the one in the cold water is still floating, whereas the other two of course are still at the bottom of the glasses.

Now we disrupted the surface tension two different ways.

One, by heating the water, you're right those particles are moving around too fast so it disrupts the surface tension.

It was weakens the bonds.

The soap does the same thing.

It actually separates those hydrogen bonds and so those screens cannot be supported.

Pretty interesting stuff.

These investigations are all ones you can try at home.

It's wise to test the waters.

So remember my friends.

- [All] Stay Curious.

- And keep experimenting.

Get your curiosity guide and see more programs at wkar.org.

- [Narrator] Support for a Curious Crew is provided by MSU Federal Credit Union offering a variety of accounts for children and teens of all ages while teaching lifelong saving habits.

More information is available at msufcu.org.

By the Consumers Energy Foundation dedicated to ensuring Michigan residents have access to world-class educational resources.

More information is available at consumersenergy.com/foundation.

Consumers Energy Foundation, supporting education and building sustainable communities in Michigan's hometowns.

And by viewers like you.

Thank you.

- I can't believe you got it on your perfect attempt.

- Okay.

- Hi Ali.

Ali, you look funny upside down.

You can try some of today's investigations at home as well after, that sounded funny.

That's exactly where I got that from.