- [Mister C] What time is it?
- [All] It's science time.
♪ Science, science, science time ♪ ♪ Let's all stop and just unwind ♪ ♪ One, two, three, four here we go ♪ ♪ Learn so much your brain explodes ♪ ♪ Lessons so cool and so fresh ♪ Feats so big you'll lose your breath ♪ ♪ Learning facts are real cool stuff ♪ ♪ Scream for more, can't get enough ♪ ♪ It's, it's science time ♪ It's fun, you best believe ♪ Explore and learn new things ♪ Come and join me please - I'm Mister C and this super smart group is my science crew.
Lyla is our notebook navigator.
Alfred is our experiment expert.
Riley is our dynamite demonstrator.
And London is our research wrangler.
Working with my team is the best.
And makes learning so much fun.
Actually, you should join us.
We're learning about inertia.
What time is it?
- [All] It's Science time.
- Welcome back to another episode of "DIY Science Time".
I'm Mister C and I'm so glad that you're here to be part of our crew today.
We're talking inertia.
That's right.
Things in motion stay in motion and things at rest stay at rest, unless acted upon by an outside force.
And I have one exciting experiment for us to try right now.
Grab some water and put it into a cup.
Take a plate, put it onto the cup.
I have a plastic plate.
I have a toilet paper roll, and I'm gonna place an egg on top of it.
This is our egg tower.
It's a system and it's sitting there and it's not going to ever do anything unless something acts on it.
So what should we do?
Hmm.
I think we should try to hit this plate out from underneath that egg and let's see if it works.
All right, here we go.
In three, two, one.
Yes, it worked.
So what happened?
It's all about inertia.
That egg wants to sit on top of that toilet paper roll until, well, we move things out from underneath it.
I think we should try this again, but I think we should try it with more cups.
What do you think?
(upbeat music) All right, get everything lined up really nicely.
One, two, three eggs.
All right, here we go.
Make sure they're lined up.
I think it looks good.
In three, two, one.
(Mister C laughing).
It worked, it worked.
I think we should try with taller tubes.
I've got paper towel rolls.
We have it set up.
And now we're gonna try this again.
I'm nervous about this one.
All right, we're gonna apply the horizontal force right here which hopefully kicks out this lunch tray, kicking out the tubes and allows the eggs to fall straight down like they've been doing.
In three, two, one.
Oh, well.
(Mister C laughs) Sometimes, kinda cracks you up.
That's okay.
No more yolking around.
We need to get to inertia.
I've got a couple of materials for this next activity that you need to check out.
Alfred, what do you have for us today?
- It's time to get moving and organize our materials.
Here's what you'll need for the first activity.
A yard stick, two juice boxes, a marker, tape, and we can't forget our science notebook.
- A science notebook is a tool that every scientist should have.
And it gives us a place to record all of our learning.
Taking good notes and being organized allows us to be better scientists.
A science notebook allows us to go back and review all the data and information we've gathered during our experiments.
Plus, it allows us to share results with other scientists who might be interested in learning more about what we've discovered.
Whenever you see the notebook pop up on the screen like this, it's a reminder that this is a good place for us to jot down new information.
You can see I've already added a title and the list of materials for today's activity.
Our crew is still going to have lots of information to collect and organize as we go through the experiment.
So keep your notebook handy.
Most importantly, the more you use the science notebook the better you'll get at taking notes and recording data.
If you don't have a science notebook yet, download a copy of Mister C's science notebook from the website.
- Newt's first law says that, "An object at rest will stay at rest unless acted upon by an outside force."
And that an object in motion will stay in motion unless it's acted upon by an outside force.
The egg tower is a great example of inertia at work.
Everything is at rest, but once we exert the horizontal force on the plate, it causes a chain reaction and allows our experiment to work successfully.
- It's the moment of a inertia you've been waiting for.
Take your yard stick and you're gonna split it in half.
You're gonna find the center of the yard stick.
A yard is 36 inches.
So if we divide a yard in half, we get to 18 inches.
So we're gonna take and mark the 18 inch increment right there.
So we know that's our center.
Now to build our wand, we have to space our juice boxes away from the center evenly.
So for this one, I'm going to go let's say five inches from the center.
So 18 plus five, one, two, three, four, five, gets me to 23 inches.
And then I have to go five inches in the other direction which is 18 minus five or 13, one, two, three, four, five.
Once we have those marked, you're gonna take your juice boxes.
Now your juice boxes may look different than my juice boxes.
That's okay.
We're gonna place them right on the mark.
And we're going to tape them down.
One here.
Whoops.
Get that on there nice and snug.
This one on here.
(upbeat music) Put that on there nice and snug.
And now we have our wand.
Wait a minute.
Yeah, I wander how strong I can get lifting these 12 ounces of juice?
Anyway, all right, here we go.
I'm gonna back up.
I'm gonna hold this out, straight out.
And what I'm going to do is I'm going to twist my hand left and right, left and right.
And I wanna see and feel how easy that is.
Remember, our juice boxes are five inches from the center.
And let's see how many times we can get it in 10 seconds.
Here we go.
Are you ready?
In three, two, one.
(upbeat music) All right, if I counted correctly, I was at 32 twists of the arm and actually I could feel it.
It wasn't too difficult, but what you just experienced after you build this it's the moment of inertia on that rotational axis.
It's the moment when you put force into this and you can feel it turn, you can feel it turn.
All right.
So what we're gonna do now is we're actually going to take the juice boxes and move them further away from the center to see if that impacts how this wand allows you to rotate it.
So we're just gonna flip this over.
We're going to untape this and hopefully we can just reuse that tape.
All right, so now what we're going to do, I wander how far should we go from the center?
Hmm.
Let's go 13 inches from the center.
So 18 minus 13 is five.
And we can double check it.
One, two, three, four, five, six, seven, eight, nine, 10, 11, 12, 13.
And then 18 plus five is 31.
Oops, 18 plus 13 is 31.
Yeah, sorry about that.
One, two, three, four, five, six, seven, eight, nine, 10, 11, 12, 13.
Getting all my numbers mixed up.
So I have those two numbers on there and I have them marked.
We're gonna take our juice box, lay it down.
Hold that there.
Tape that up, tape that underneath.
We're gonna do the same for the other side.
Put that down, lift it up.
All right.
So already, it feels different.
Did I say 32 last time?
I think it was 32.
So now we're going to do the same thing.
The juice boxes are on there nice and snug.
I'm going to this up and I'm going to twist it the same.
I'm gonna see how many times I can twist it back and forth in about 10 seconds.
And here we go.
In three, two, one.
(upbeat music) All right, that was about 10 seconds.
I got to 20, 20.
That is literally experiencing the moment of inertia.
The moment of inertia.
- The moment of inertia occurs when you start turning the yardstick.
Once you apply a rotational force, the juice boxes begin to move.
The closer the juice boxes are to the center of the yard stick, the easier it is to start rotating that stick.
When the juice boxes are moved further away, it requires a greater force to get the mass moving.
And it's also more difficult to change directions.
- Let's get the momentum going and get this information added to our notebook.
I added a sketch of the egg tower and the inertia wand and included the definition for Newton's first law.
I wander what might happen if you try to tape different objects to the yardstick.
Maybe a heavier object on one end and a lighter object on the other end.
- Here's another really cool activity you can do at home to explore inertia.
Make a ring from some cardboard, place the ring on top of an empty bottle, and carefully place a hex nut or coin on top of the ring.
You've built another inertia tower.
Quickly pull the ring to either side and yahtzee!
The hex nut falls directly into the bottle.
Don't worry if you don't get it to work on the first time.
It can be tricky to get it to line up perfectly.
- In front of me, I have 50 feet of beads.
We call these inertia beads.
These beads are all connected through a string, but what's really interesting is they're all sitting on the table and they're not moving, but they have inertia.
Because an object at rest wants to stay at rest unless acted upon by an outside force.
What we're going to do is I'm going to take this little end here with the red beads and I'm just going o pull it off the table.
And I wanna see what happens to the rest of the beads.
Are you ready?
Let's give it a try.
All right, three, two, one.
(Mister C laughing) (Mister C laughing) That was so cool.
All right, I need to pick it up so we can do another one.
Now we know gravity is pulling down on the cup.
I can feel the force of gravity because it's making me hold this cup up.
Here's the thing, I'm gonna pull this out.
And I want you to pay attention to the beads and see if it works.
Alright, here we go.
Three, two, one.
(upbeat music) That is so awesome.
The first bead gets pulled over the ledge.
Gravity's pulling down on it.
It's connected to the next bead and says to the other bead, you're coming with me, I'm in motion.
So they stay connected.
They're pulling each other out of this container.
But I wonder, it really wasn't shooting out too high out of the top.
What if we have a higher drop?
What if, instead of this being from about a foot from the cup to the table, what if we went to a park and we held it really high off the ground to see if we could get the beads to shoot out higher?
I think we should give that a try.
Don't you think?
(upbeat music) (Mister C laughs) - There's nothing more fun than breaking a water balloon on a hot summer day.
Let's look at that again in slow motion.
Mister C is applying an upward force that holds up the balloon and the water inside the balloon.
These objects are at rest, but still have inertia.
We can see the elastic balloon rip upwards quickly once the needle pierces the balloon.
But the water, the water appears to be suspended in mid air.
Once the water realizes the balloon is gone, it falls to the ground because of gravity.
- Did you know that a stack of five quarters weighs one ounce?
You can use that math to have some fun playing tricks on friends and family.
Carefully stack your quarters on top of a dollar bill, challenge your friends to pull the dollar off the bottle without knocking over any of the quarters.
Can it be done?
You betcha.
With one quick downward swipe, hit the dollar bill with your finger.
The dollar will slide out easily because there is not much friction between the bottle and the dollar and the quarters.
The stack of quarters stays on top of the bottle.
- Thanks, London.
That was an amazing experiment.
If I had a quarter for every time my crew had an amazing idea, I would be rich.
Which leads me to another experiment.
We're building a centripetal force board.
That's right.
What you need for this is a piece of cardboard, it can be any size technically.
It can be a piece of cardboard or a piece of wood.
You also need some string.
I have a little push pin to start my hole.
I have a pen to make the holes bigger.
A cup with some mass.
In this case, I'm using pennies.
A penny for your thoughts.
All right, what we're gonna do is we're going to take our push pin and put a hole into each of the four corners.
I'm going to take my pen and I'm going to just make the hole bigger.
We're going to take our string and we're going to unravel our string and make it, get four pieces that are the same length.
So I'm just going to use the string and measure it against itself.
Now what we're going to do is take our first piece of string, put it down into the hole and I'm actually going to bring it up.
And I'm going to use and tie it against itself like this.
So that I know it can't slip back through the hole.
I'm gonna repeat that three more times.
(upbeat music) And the last one.
So now what we're going to do is we're going to lift this up and bring all these strings to the top and the goal is to tie them off so that all the strings have the same tension from the board.
So I think we're pretty close here.
(upbeat music) Perfect.
Might be a little bit long.
I'm gonna make it a little bit shorter.
You can always change the length.
There we go.
All right, we've got our centripetal force board.
So now, I'm gonna cut off a little bit of the string.
So now that we have that, now we can add our mass to it.
And I can start to swing it just like this.
Now, you can see here that it wants to rotate, right?
It's rotating from the centerpiece here.
This is the centripetal force.
And centripetal force means that it's pulling towards the center, but our weight, our pennies, are trying to push out because of inertia.
They're staying in motion.
And what we're going to do is I'm going to try to rotate this over my head, up and around.
And I'm just making sure it's okay.
I'm gonna slide back.
If I do this correctly.
I don't know if it's gonna work.
Do you think the pennies are gonna fall out or do you think the pennies are going to stay in the cup?
That is the question.
In three, two, one.
Whoa.
That was so cool, it worked.
It actually worked.
And I thought it would because centripetal force is a force that is exerted inwards to the center of the system.
So, the force is actually pushing in because I'm keeping all of this tight.
The board, everything, wants to stay connected to the center, but inertia, inertia wants these pennies to push up and away.
But when the board and the pennies meet, it keeps them all together in the same place.
So the question is, if you were to take this outside, how many times could you get your centripetal force board to spin without losing control of the pennies and having shoot all over the place?
In fact, if it's warm enough, instead of having pennies in your cup, you could actually put some water inside and have some fun to see if the water would actually come spilling out.
Give it a try, build your own centripetal force board.
- The slinky was accidentally invented by mechanical engineer, Richard James in 1943.
Mister C has extended a slinky and is going to release it.
Make a prediction on how the slinky will fall.
Will the top and bottom fall at the same time?
Will one fall before the other?
Will the bottom shoot upwards?
Let's give it a try.
Three, two, one.
Did you expect that to happen?
Gravity is exerting a downward force on the slinky.
And Mister C's hand is applying an equal upward force to hold it in place.
Once he let's go of the top ring, that ring begins to fall.
The rest of the lower rings remain suspended.
The lower rings don't know that Mister C let go until the ring above them begins to fall.
Eventually, the last ring gets the signal that there is no longer any upward force.
And the whole thing comes crashing to the ground.
- I am going to show you one of the coolest things I've been working on.
It's called an inertia walker.
I've got this ramp here that I built out of a cardboard box that we have here at the house.
And then I have this rectangular prism thing.
And I'm gonna show you what it does.
So if I hold this here and I let go.
I've got another one, let's try this one.
That was awesome.
And you're probably wondering how does that thing work?
Well, it's all about inertia.
All right, let's clean this up.
Let's build one together.
My inertia walker, this here, it's powered by one simple thing.
This metal steel ball, it's actually really heavy and has a lot of mass to it.
And what happens is, when this ball is rolling down that ramp, the ball wants to keep going because an object in motion wants to stay in motion.
But what we're trying to do is harness the power of that ball.
And because the ball is going from one side to the other side, it's actually causing that inertia walker to flip over, over and over and over.
Now, you can build an inertia walker using the template that we have at "DIY Science Time".
Or you can build one from scratch using paper towel rolls, some egg carton pieces, and some tape.
It's totally up to you.
And they all work in different ways.
That's half the fun is using the engineering design process to figure it out.
I'm going to use my newest and latest design right here.
(upbeat music) So as you can see here on this design, we have these little tabs and these tabs are going to allow me to fold the paper over and kind of help me keep it in place while I tape it.
And then we're gonna put a steel ball inside before we tape it up.
All right, so we have our inertia walker built.
Now really quickly before I bring the ramp back out, you can see that this iteration is much more narrow and I'm hoping that this allows the steel ball to literally just roll back and forth and will allow our walker to walk more straight down the ramp.
All right, let's give it a try.
Let's get our ramp back out.
All right, we've got our ramp set up and we are ready to test the latest and greatest "DIY Science Time" inertia walker.
Here we go.
In three, two, one.
Success.
Onto the ground.
Onto the ground, that was awesome.
The coolest thing is if you start using it and you're like, "Oh, I wanna change some things."
Make changes to it.
That's what this is all about.
Building on each other's understanding and making something better than it originally was.
That's the whole piece to the engineering design challenge.
The engineering design process allows me to take something that I started with like this, where I took a piece of cardboard, a paper towel tube, egg carton pieces, some tape, and then I glued on salt to make it have more friction and resistance so that it actually walks down the ramp just like that.
Have some fun, make some changes, modify it, enjoy.
And most importantly, get moving because an object in motion, always stays in motion.
- I'd say that the first law of our science crew is that a team in motion, stays in motion.
Let's get moving on all these notes.
I've added some really great info to our notebook.
I wonder if you could test the centripetal force board with longer strings.
Do you think that would still work?
What about a taller egg tower?
How tall do you think you could make the tower and still have the experiment work?
That would be eggciting to see.
- Whoa.
That was almost exactly what I didn't wanna have happen, break an egg.
Speaking of eggs, what an excellent day learning about inertia today.
We had our inertia beads, our inertia wand.
We had our centripetal force board, our inertia walker.
And if you don't have it yet, use your inertia.
Head over to the website and download a copy of the notebook so that you can keep track of all these experiments and all the changes you're going to make when you try them yourselves.
What an amazing day.
So much fun, so much energy and so much inertia.
That was excellent.
Keep learning, keep exploring, keep having fun.
And remember, science is wherever you are.
Take care, bye.
♪ It's science time Didn't work that time either.
That is experiencing.
♪ It's science time All right, three, two, one.
♪ It's science time ♪ It's science time ♪ It's so much fun ♪ Learning fun for everyone Speaking of which, so now that we have all the (indistinct).
♪ Yes, you best believe
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