
Conservation of Mass
3/14/2021 | 26m 46sVideo has Closed Captions
Measuring mass with marble fizz and massive bricks!
Measuring mass with marble fizz and massive bricks! Matter cannot be created nor destroyed. But weight, there’s more to know about the Conservation of Mass! STEM Challenge: Designing a Simple Balance Curious About Careers: Astronomer Jillian Bellovary
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Curious Crew is a local public television program presented by WKAR
Support for Curious Crew is provided by
Michigan State University Federal Credit Union (MSUFCU)
Consumers Energy Foundation

Conservation of Mass
3/14/2021 | 26m 46sVideo has Closed Captions
Measuring mass with marble fizz and massive bricks! Matter cannot be created nor destroyed. But weight, there’s more to know about the Conservation of Mass! STEM Challenge: Designing a Simple Balance Curious About Careers: Astronomer Jillian Bellovary
Problems playing video? | Closed Captioning Feedback
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Learn Moreabout PBS online sponsorship- Are you feeling curious?
- Yeah.
- Today on Curious Crew, (Rob laughs) we use chemistry and physics to weigh in on the Law of, the mass is all still there, the Conservation of Mass.
I'm getting a little afraid right now.
- [Janellyn] Support for 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.
Also 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.
(soft upbeat music) - Hi, I'm Rob Stephenson and this is?
- Curious Crew.
- That's right, welcome to the show everybody.
We always like to start every episode with a couple of discrepant events because discrepant events stimulate?
- Curiosity.
- That's exactly right.
And I've got a couple of fun ones for you here.
I've got two digital scales.
I've got two bottles, both with balloons on top and we'll talk about that in just a minute.
But first thing I wanna point out to you is, I'm gonna turn on this particular digital scale because I wanna get a mass reading on this bottle.
I put some vinegar in this bottle and you know me I had to do something to the balloon.
So, guess what I put in the balloon.
I put in there baking soda, and I'm actually gonna drop the baking soda into the vinegar.
Finney, what do you think is gonna happen?
- I think that the two will combine and they will cause a chemical reaction which will inflate the balloon.
- You'll notice I've got some goggles here.
Okay, I'm going to place this on the scale and I'm gonna let you know what the mass is coming in at 341 grams 0.96.
Now, I'm gonna put this on, safety first of course and I'm going to sprinkle this in.
Let's see if Finney's prediction is right.
Oh dear, oh my, oh my, oh my, oh my.
Okay, some pretty good predictions there Finney and I'm getting a little afraid right now and I'm just going to let that do its thing.
Now you might've noticed I actually put some tape around there just to be a little safer so it didn't come flying off.
I think I can probably pull off my goggles now and let me tell you what's going on in this one.
I actually have some steel wool and I have some on the paper towel here too.
Jacob, I know you've got some.
How would you describe that steel wool right there?
- Like shiny and stiff.
- Now you happen to see some other steel wool after it had been submerged in vinegar and placed inside this flask.
And how would you describe what that's like now?
- This one is like red and brittle.
- Okay, now I'm gonna do the same thing.
I'm gonna put this one on and in fact we've already had a reaction take place on this one.
This one's coming in at 221.5 grams.
When I put this on, there was a little bit of air inside this balloon and there's no longer any air inside this balloon.
So, we've gotta figure that thing out.
Now, wait a minute.
Do you guys remember what the measurement was over here?
Because I've got a different measurement.
This is now coming in at 339.57 grams.
That's a little perplexing.
I happened to measure this one before I started and guess what?
It was 221.5, it's the same.
But that one, is not the same.
What's going on here?
We've gotta figure this thing out.
Does anybody have a guess what we're gonna talk about today?
Sasha, what do you think?
- Does it have something to do with mass?
- Great thinking, we are gonna talk about mass.
Exactly, we're actually gonna talk about the conservation of mass, and to figure this out I'm gonna need a few of you to do some modeling during the show.
Who would like to take part in some modeling moments today?
All right, I see a lot of people want to, okay.
Jacob, Rishabh, Janellyn.
You guys are gonna be working throughout the show.
Use the information that you get to get some clues revise your thinking and then you can try to explain this at the end.
Stick around, it's gonna be fun.
(soft upbeat music) - Okay, let's see if we can figure this out.
- Why would the wool change color and make the balloon get compressed?
- Well, it must have something to do with the steel rusting making that color change but the total mass stayed the same, unlike with the inflating balloon - Mixing the vinegar and the baking soda produces the carbon dioxide gas.
And that must be what's blowing up the other balloon.
(soft upbeat music) - [Rob] When you look around, you are surrounded by matter.
Things that are made of tiny particles that take up space.
We can't see those tiny atoms and compounds that make up things because they're too small.
But as they combine their total mass increases they have more matter and that makes it easier to observe.
The Law of Conservation of Mass says that those tiny particles cannot be created or destroyed but they can rearrange to form new substances with the same total mass.
So, weren't those discrepant events interesting you guys?
- Yeah.
- Excellent.
Well, I've got a couple of fun activities that we're gonna do here.
And first thing I wanna point out to you is I have this digital scale and I'm just gonna turn it on and we're just gonna set it to grams like we did before so we can measure some mass.
I'm gonna place a glass of water on top and then I'm going to drop in this little tiny magnet inside the water.
Let it go all the way to the bottom, and the last thing I'm gonna put on here is this tablespoon that has some powdered drink, and I wanna know what's gonna happen.
Right now I have 724 grams.
What will happen after I put this powder inside here we're gonna stir it up on the stir plate, and then in a couple of minutes, I'm gonna put it back on to the scale to see what happens.
What do you think is gonna happen?
- I think that the mass will be less because I think that the powder will dissolve into the water.
So there will be less to weigh.
- So you're thinking about that powder dissolving and we can sorta see that, we've got a mixture going on right now, don't we?
And of course, I'm gonna put it back on and to be perfectly fair I'm now gonna put the empty tablespoon back on there.
And do you remember what it was before?
It was 724.
And guess what it is now?
It is 724.
Interestingly, the mass is all still there even though we got a mixture going on, it's all still there.
Let's think about it this way.
I have these buildings bricks right here and I'm going to put this on my scale and I think Sasha's got one too.
Sasha, do me a favor.
I want you to put your building bricks on your digital scale.
Make sure your digital scale is on.
What's the mass of your bricks?
- 67 - 67.
Mine's coming in at 99.
Sasha, I want you to rearrange your bricks and then put it back on.
Now, I just changed mine.
I'm gonna put it back on the scale here.
It said it was 99 before it's still 99.
Sasha is yours the same as it was before?
- Yup, 67.
- How about that?
Okay, now it's interesting.
Every single one of these bricks is kind of like if we can imagine them like different atoms we are just rearranging the bricks or rearranging the atoms just like over here in the drink.
They're not gone.
It may be rearranged, but it's all still there.
Mass is the amount of matter in an object.
Think about a brick.
If we could add up all the atoms in that brick we could figure out its total mass.
But remember those particles are so small.
Counting all of them would be too hard.
So, engineers develop balances that could be used to compare the mass between objects.
They use known masses of grams or kilograms on one side of the balance and the brick on the other.
When the balance is level, you found the mass of the brick.
This one is 3.1 kilograms.
That's a lot of mass.
(upbeat music) Okay, so I've got a couple of bottles here, you guys.
I want you to notice them closely.
I've got the caps off this one over here has no cap.
Now, I'm gonna turn on both of my scales and then I've got these antacid tablets.
So, I got a question for you, you guys.
Have either of you ever had to take an antacid tablet before?
- Yes.
- Genesis, you have.
So, what does it do when you put the tablet in water?
- It starts to fizz up and make all kinds of bubbles inside of the water.
- [Rob] Okay, I'm going to put both of these on the scale.
And in fact, I wanna make sure I have the cap over here and then I've broken these tablets into a couple of pieces so I can drop them through the top of the bottle.
And so what I wanna do now is just get a measurement of the mass.
So this one is coming in at 76.7 and this one's coming in at 76.8 which makes sense because there's a cap over there.
So, here's what we're gonna do.
I'm gonna put this one in first and we're gonna swirl it around and let it do its thing for just one second.
Oh, there it goes that fizzing that you were talking about and I'm gonna do the same thing over here but the difference is I'm going to put the cap on it.
Okay.
So cap is on there, swishing it around and I'm gonna let it do its thing over there.
The first thing I want to discuss is that gas.
Jacob, what gas do you think is coming off of that?
- Is it carbon dioxide?
- It is.
It is carbon dioxide.
Good job.
So the interesting thing about this is, this is called sodium bicarbonate.
And when you put it in with water there's a chemical reaction.
We can see it.
It's that fizzing going on.
It's now turning into sodium hydroxide and water and carbon dioxide gas.
Those are going to be the products.
Now, interestingly enough the mass measure has gone down on this one.
This one it's the same.
Now, let's think about that.
This one stayed the same.
This one went down.
Why might that be the case?
Let's think about that.
Could it be that this one has no cap?
That kinda makes sense, doesn't it?
So Jacob was talking about the gas escaping and in fact it is that gas is actually escaping out into the room.
It still exists, but it's way harder to detect on the mass scale right now.
Over here I've got a closed system.
So I can still measure that gas along with the entire rest of the bottle, cap and water.
The Law of Conservation of Mass says that in a closed system all of that mass is still measurable and detectable.
Sometimes it can escape out but it's not gone, at least not very far away.
Nice job, you guys.
Have you ever watched a log burn up in a campfire?
It may seem like that matter was destroyed but the matter in that log had a chemical reaction.
The wood is made of carbon, hydrogen and oxygen atoms.
But when the wood burns, some of the atoms separate and go into the air, combine with oxygen and become water vapor and carbon dioxide.
Other particles are also released.
But if you could measure all those released gas particles, smoke and leftover ash it would be the same total mass as when it started.
That's the Law of Conservation of Mass.
(soft upbeat music) - [Male Voice] STEM challenge.
- So, have you guys been having fun today?
- Yeah.
Awesome, now I've got a really interesting STEM challenge for you today.
We've been doing a lot with these digital scales and digital scales are great to find mass, but it's kind of a trick because we're actually using the force of gravity and then the scale's doing a calculation to find mass.
When we wanna find mass, we use a balance and that's what we're gonna do today.
I am gonna challenge you to make your own simple balance and then start checking the mass of different objects that you've got.
You guys have some materials, are you guys ready?
- Yeah.
- All right, let's go ahead and get started.
(soft upbeat music) - In this experiment, we are building balances to test the mass of multiple different objects.
- I'm using this metal hanger thingy.
Plastic hanger, weights and two bins like this.
- I am using a wooden board, a piece of pipe and two U shaped hangers.
Man, I should have put this on the thing first and then put the hooks over it.
- Mine has a hook and I had to put a binder clip on a straw.
So, that took me a bit of trial and error to make sure it was perfectly balanced so the balance would actually work.
- It's really equal almost.
- I used the hangers to clamp the pipe onto the board so that the board and the pipe together act kind of like a seesaw so that you can put a certain amount of mass on one end and you can test it against the mass of another object.
- [Genesis] This one's heavier.
I'm really proud of how the end game turned out.
I was kind of skeptical 'cause it was stuff you could find around your home, like straws and binder clips but it actually worked pretty well.
Yes, we have done it.
- What I love about doing experiments like this, is the fact that you're always learning something new.
- So it looks like you guys have been busy, you're ready to show us your pan balances?
- Yes.
- Awesome.
All right, Finney, let's start with you.
You tested some items and show us one of the items that you figured out the mass on.
- This is something that I printed on a 3D printer.
I couldn't figure out its exact mass, but I could figure out that it was somewhere between 73 and 80 grams.
- Nice job and I like that whole idea of a seesaw balance.
Excellent job.
Let's go to Sasha, next.
Sasha, yours is hanging.
What's going on there?
- I have a metal stick that has a hanger at the end of it and then there's a hanger hanging from that and then two boxes.
- So tell me one of the things that you investigated to find the mass.
- I tested this pair of sunglasses and I started by putting 80 grams on the one side and then the sunglasses on the other side.
And it was less, so I know it's less than 80 but then when I put it with the 20, it was more.
So, I think it's somewhere around 40 grams.
- So finding that unknown mass.
Great job.
Okay, Genesis, how about you?
- So mine is like Sasha's little sister.
It's the same concept.
There's a little hook that holds like some cups.
So, one of the things that I tested was some nail polish and I was actually able to find the exact weight.
So, I did 50 grams and I knew that that was a bit too much.
So, then I ended up putting in 25 grams and then I put all four of my metal washers which added up to 10 and it gives me the exact weight.
So my nail polish was 35 grams - 35 grams.
Well done, you guys made some great designs there.
You can try making your own simple balance with materials just like they did at home.
And in fact, if you're trying to figure out a great way to come up with a system as a counter measure, coins can be super useful.
In fact, nickels, they actually weigh in at five grams which is kind of appropriate, I think.
And in fact, a penny, if it was minted after 1982 is two and a half grams.
So you can use some of those to help find the mass of some of your unknown objects.
Great job, you guys.
The Law of Conservation of Mass was discovered by a French chemist named Antoine Lavoisier in 1789.
He ran many different experiments with chemical reactions all inside a sealed jar.
Because the jar was a closed system, he could measure the total mass before, during and after the reaction, it was always the same.
He realized the matter wasn't created or destroyed but that the particles were rearranging.
Great job, Antoine.
(upbeat music) So, we've been doing a lot with chemical reactions today, haven't we you guys - We definitely have.
- I know both of you have some marble at home and how would you describe that marble, Rishabh?
- I would describe this marble as white, pointy and rough.
- Okay, great and Janellyn, what would you add?
I would add that the marble definitely has very defined grooves and it gets dirty very easily.
- Okay.
So, now I have a wondering, does it have mass?
- Yes.
- Of course, it has mass.
And I'm going to put this on the scale so I can find out the mass, but I also am going to put on this glass.
Now, even though this looks like water, it is not water.
This is actually hydrochloric acid and Janellyn, do you have a guess what might happen if I drop the marble into the acid?
- Will it begin to dissolve?
- I think we should find out, but you know what?
Safety first, let's just take every precaution.
I'm gonna drop this in real carefully and see what it starts to do.
So, it does look like there's some dissolving going on and I'm seeing some bubbles coming off of there.
Okay now, that's pretty interesting.
I'm also keeping an eye on the scale because as it is right now, it's coming in at 508.9 grams and I'm curious to know what's gonna happen in just a couple of minutes.
I also wanna direct your attention to these over here 'cause I've got some really interesting chemicals that we're gonna mix together.
I have potassium iodide and I have lead nitrate and I'm gonna put both of these on the scale.
So, we get a sense of what our total mass is with the cylinders as well.
This is coming in at 371.9 grams.
Rishabh, take a guess.
What might happen if I combined these two chemicals?
What might it do?
- It might bubble or fizzle.
- [Rob] Okay.
- He wants bubbles.
He wants fizzles.
All right, I'm going to pour this in and then I'm gonna put this right back down on the scale.
(Rob laughs) Okay, so clearly we have a chemical reaction taking place, don't we?
Now, what's amazing is, in this example we've got potassium iodide and those atoms are actually separating and we had lead nitrate and those atoms are separating.
And in fact, we now have something that is lead iodide and potassium nitrate.
You'll notice that one of them has this yellow color.
It's almost a solid yellow.
The other has a white solid.
This is very unusual.
All of the mass is still there.
And in fact, the mass has not changed.
We have a chemical reaction, but the mass has not changed.
Now over here, in fact, our marble is still bubbling and dissolving and you'll notice it's really cloudy in there.
This, in fact, the mass went down.
We actually had bubbles coming off and I bet you can guess what kind of gas was coming off of this?
It is carbon dioxide and we actually have left inside calcium chloride and water.
Now you might be wondering, "Okay, why did the scale go down?"
Well, the carbon dioxide gas is now all around the room.
It's a lot harder to detect on the scale now, isn't it?
Isn't that amazing?
Chemical reactions, the products that result from them but gotta remember the mass is always present.
Isn't that cool, you guys?
- Yeah.
- Definitely.
- [Rob] We could see how the mass stayed the same in the surprising reactants investigation but sometimes a chemical reaction produces gases that are harder to measure.
This happens when things burn or when a reaction produces a bubbling gas like the marble fizz.
It's important to remember that those atoms still exist.
Even if we can't see them in the air.
Remember, it's the law.
(soft upbeat music) - Are you curious about careers in science?
- Hi, I'm Genesis and today I'm here with Dr. Jillian Bellovary.
Jillian, can you tell me where you are and what you do?
- I am in New York city and I am an astronomer and a professor.
- Tell me what are you do at your job?
- I study things in space.
In particular, I study black holes.
A black hole is something that is so dense that nothing can escape it, not even light.
By using computer simulations, I can make predictions about what's going on in the universe and then I can let my colleagues know what I'm predicting and I ask them to go on and look for the things that I'm telling them that are there.
And maybe sometimes they find them which is pretty exciting.
- What's the most rewarding part of your job?
- Mentoring students.
I love watching students have the like mind blown moment.
- I am over the moon that I get to learn about astronomy with Jillian Bellovary.
Explore your possibilities.
- And now, back to Curious Crew.
- [Rob] There you go Rishabh.
We got the wave going on, man.
The wave going on.
(upbeat music) - We know that in both discrepant events, there's a chemical reaction taking place and that the particles get rearranged.
Kind of like Sasha's building blocks or the power drink.
The total mass is the same.
- And Genesis and I saw how the tablets fizz but the open bottle went down in mass because some of the particles escape into the room the closed one stayed the same.
- That's right, and in Dr.
Rob's discrepant events both bottles were close too.
But I think the inflating balloon might've changed the results.
- So you guys had fun learning about the Conservation of Mass today?
- Yeah.
- Awesome.
Now, I know some of you have been hard at work trying to figure out these discrepant events that we did at the beginning of the episode.
Jacob, what have you guys figured out so far?
- We've seen a lot of chemical reactions like the wool rusting from the air in the bottle.
- How do you know there was a chemical reaction with the steel wool?
- Because the properties changed and it went from shiny and stiff to red and brittle.
- When you put this into vinegar, it actually removes the wax coating that is on the steel wool and suddenly the iron starts to interact with the oxygen and there's your chemical reaction, Jacob.
And we actually have something created, iron oxide which is that red rusty that you see on the steel wool.
Excellent job.
The other thing that's interesting because that oxygen was involved in the chemical reaction, there's fewer air particles hitting the balloon on the inside as at the beginning and so it actually gets squished.
Nice job.
So what's happening over here in this system?
Rishabh, what have you guys figured out there?
- Well, we know that the carbon dioxide gas is produced from the chemical reaction between the baking soda and the vinegar, just like how we saw gas produced with the antacid tablet and the marble and the acid.
Each time the mass went down, the system was open because the particles went into the room.
- So if they go out into the room much harder to detect on the scale, right?
Excellent job.
Okay, and we know that the Law of Conservation of Mass says that all the matter's going to be there in a closed system, and yet this is closed and when we measured it on the scale, we saw the mass go down.
How do we explain that part, Janellyn?
What do you guys think?
- We know that digital scales figure out mass by calculating an object's weight from the Earth's gravity, whereas a simple balance can compare the masses.
We think that because the balloon is inflating the total volume of the system changes and that affects the reading on the digital scale.
- So, as the volume changes, we actually get some air particles interacting with the balloon and we even have air particles bouncing off the underside.
This has a buoyancy effect.
Even some lift, you can even see that.
And because of that buoyancy, it actually changes the force applied to the scale.
So the scales kinda tricked into believing that the mass has gone down.
When in fact we know it has not, nothing has been created or destroyed.
All of those particles are still there.
Remember that's the law.
So, remember my friends.
- Stay curious.
- And keep experimenting.
Get your curiosity guide and see more programs at wkar.org.
- [Janellyn] Support for 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.
Also 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.
(Genesis sings) - [Janellyn] That sounded good (Rob laughs) - Full of energy.
Full of excitement.
- Yeah, energy, energy.
(Rob laughs) That's hilarious.
(upbeat music)
Support for PBS provided by:
Curious Crew is a local public television program presented by WKAR
Support for Curious Crew is provided by
Michigan State University Federal Credit Union (MSUFCU)
Consumers Energy Foundation