Hello, I'm Mrs. Niven, and today we're going to be looking at mixtures and the equipment we might use when we create or investigate mixtures.

And this is gonna help us as we try to answer that big question of how can we explain how substances behave.

By the end of this lesson, you should be able to identify and name some common laboratory equipment that is used when we create or investigate mixtures.

You may be familiar with some of the equipment already, but it is very important that you feel confident being able to identify and choose appropriate equipment as we go forward in our journey through science.

So let's get started.

The keywords that we'll be using in today's lesson include apparatus, mass, and volume.

Now the next slide will show the definitions of these words being used in a sentence, and you may find it helpful to pause the video here to read through them, or jot them down before continuing.

So today's lesson will be looking at two main things, the equipment that's used for measuring and heating, and then we'll start to look at the equipment that's used specifically for mixing.

So let's get started by looking at the equipment that's used for measuring and heating.

Now, if you've ever seen inside a science lab or seen one on television, you will have seen the large variety of equipment that can be found in a science lab.

When we use the term equipment, we're talking about a generic hold-all term to represent all of the equipment that you might be able to find for an investigation.

Today we're gonna be talking more specifically using that term apparatus.

Apparatus is a word we use to represent a very specific technical piece of equipment that has been designed for a particular use.

So that's what we're talking about today, those particular uses and what is it about that piece of equipment that allows it to be used for that specific use.

When a scientist makes a choice of apparatus, they need to consider very carefully what exactly is being measured.

Are we measuring the length of something? Are we going to be measuring the time it takes for something to occur? Regardless of what we're actually measuring, those pieces of equipment or those apparatus are some of the easiest to locate within the lab, and that's because they're distinguished by a scale of numbers along its side, or will provide a range of numbers on its display.

When we're talking about making a mixture, the most common measurements that you will need to make are those for a substance's mass, or for a substance's volume.

So let's take a closer look at those two aspects about a substance.

Now you may remember that all matter is made up of tiny particles and we have here a diagram showing how the particles are arranged in a solid.

When we're talking about a substance's or an object's mass, what we're really talking about is how much matter that object or substance actually has.

Now in science, we measure mass using those units of grammes represented by the lowercase g.

You will have come across mass in other ways, though, in your life.

For instance, a person might be given the mass in kilogrammes or stone, the mass of a car might be given in tonnes, and the mass of a bag of flour or a bag of sugar may be given in pounds.

But whilst they're all representing masses, the units that we use specifically in science is grammes, and we measure that using a balance.

Now the balances come in varieties of types, but we tend to use an electronic balance at the moment because it gives us a far more precise measurement.

Now a material's volume on the other hand represents how much 3D space it actually occupies, how much space it takes up.

And we represent the object's volume using the units of centimetres cubed represented by the lowercase cm and the raised three.

Now, how do we measure an object's volume depends on the type of object or material we are trying to measure.

For instance, if we're talking about cubic materials, and I'm thinking about something like a wooden block or a cardboard box, you'd end up using a ruler because using that you can measure that object's length, it's width, and its height, and those measurements would be multiplied together and give you the 3D volume of that particular cubic object.

When we're making a mixture in the lab, we are less likely to use a cubic material than we are, something like a liquid, or something in the gas state.

So we're going to need to use a different measuring apparatus to find the volume of those materials.

You're more likely to use something like a measuring cylinder or a pipette.

Now which of those apparatus you choose to use depends on a few things.

So let's take a closer look at both of these pieces of equipment.

Now the great thing about a measuring cylinder is that it comes in many different sizes, but we'd only really choose one if we're going to be measuring volumes of five cm cubed or more.

So what is it about a measuring cylinder that makes it particularly useful for larger volumes? Well, there's a few different things.

The first one is that it is designed with a spout.

That helps us to pour the contents out in a very controlled way once that volume has been measured.

The second thing we'll notice about it is that a measuring cylinder has a narrow body and that allows for really accurate measuring.

This is something we'll come back to in a moment.

and the best thing I would say about a measuring cylinder, but sadly one that's many people forget about is that it has a very wide flat base and that helps to keep the measuring cylinders stable when you are filling it, and that's particularly useful when you are measuring larger volumes.

Now a dropping pipette on the other hand would be used if you are going to be measuring any volumes that are less than five centimetres cubed.

And it might be a little tricky to see the line markings on the side there, but they are there.

You can probably see them a little bit better in this picture.

But what we notice is that there are very similar features between the measuring cylinder and the pipette.

For instance, if you remember, the measuring cylinder had a spout at the top for very controlled transfer of its contents to somewhere else.

A dropping pipette also has a feature that allows controlled transfer of those contents, and that's that bulb at the top, which tends to be quite flexible, that is allowing that control.

The other common feature that we see here is it also has a narrow body used for more accurate measuring.

But also like the measuring cylinder, it's the bottom or the base of this apparatus that makes it unique for a particular purpose.

The dropping pipette has a narrow tapered tip, and what that allows us to do is to create really precise individual droplets.

So the combination of that flexible bulb and the narrow tapered tip means that we can control transfer drop by drop, one substance into another container, which is incredibly useful for making some observations during chemical reactions or if we want the transfer to be ridiculously slow.

Now you may remember that both the measuring cylinder and the pipette have narrow bodies and that allows for more accurate measurements of the substances within them, and that's because of the meniscus that they produce.

Now a meniscus is simply a curve of a substance within a container.

This will happen in things like a sauce pan, in your bowl of cereal with the milk, or orange juice, or apple juice in your glass, a meniscus will be present.

But what we see here is that the more narrow that container, the stronger the curve of the fluid or the more pronounced the meniscus that we have in it.

That means that when I'm reading off the scales on that particular measuring piece of apparatus, I have a more accurate measurement.

For instance, in this picture, I can see that the volume of the fluid in it is 6.

0 centimetres cubed, not 6.

1, not 5.

9, 6.

0 centimetres cubed.

So a narrow body is incredibly useful for accurate measurements.

Okay, time for a quick check.

True or false.

"There is only one way in which to measure a substance's volume." Well done if you said false.

Now, which of these statements then best justifies that choice? Is it that, "A material's volume can only be calculated by multiplying its length, width, and height," or is it that, "Volume can be measured using different pieces of apparatus"? Well done if you chose b, "Volume can be measured using different pieces of apparatus." Let's try another one.

"Why is the narrow body of a measuring cylinder useful?" Is it that it a, "Keeps it stable when filling," b, "Helps when pouring out contents," or c, "Allows for more accurate measurements"? Well done if you said c.

A narrow body, "Allows for more accurate measurements." Okay, let's move on to some of the equipment that you would use for heating.

So the first thing you'd want to get out if you are planning on heating material is your heat proof mat.

And that's because it's going to protect any work surfaces from any damage that could potentially happen.

The next thing you'll get out is the Bunsen burner.

Now that is used then to heat, sterilise, or even combust, and that means burn, different objects or materials that you hold in its flame.

Now the tendency is for people to get the Bunsen burner out 'cause they're super excited to be using a flame and forgetting that heat proof map.

So I'm gonna challenge you to always get the heat proof map out first and then your Bunsen burner for safety's sake.

Some other equipment that you might use when heating a material is a tripod, gauze, or a test tube holder.

Now a tripod is used to elevate some larger mixing containers over that Bunsen burner flame so you are not having to hold it yourself, that can be quite dangerous.

On top of a tripod, you might put a thin piece of mesh wire, which is known as gauze.

And what that does is support and protects the containers that are being elevated by the tripod.

Now if you're not using one of the larger mixing containers, you might be using a small glass tube and want to heat the material that's in that.

You'd use then, your test tube holder holding those glass tubes over the flame.

Now some other equipment that you might come across when making or investigating a mixture is an evaporation dish, and a thermometer.

Now an evaporation dish does exactly what it says on the tin.

It helps liquids to quickly evaporate.

And if you've ever watched a pot boil, you'll know it can take a while.

This particular apparatus is designed to make that process happen a little bit faster.

A thermometer on the other hand then will measure or monitor the temperature of a substance.

And you might be looking at that and thinking, "Wait a second, there's a scale of numbers on the side.

I thought those apparatus was used for measuring" and you'd be exactly right.

This thermometer could be used for either or.

It can be used when your heating materials to monitor, or measure the temperature, and it could also be using for measuring.

So this is one of those unique pieces of apparatus that can be used for a variety of purposes.

Right.

Time for a quick check.

Which apparatus is used to hold glass tubes while they are heated, a, b, or c? Well done if you said c.

Those are our test tube holders.

a was the Bunsen burner, which is what would do the heating.

And b is a tripod which is used for holding larger containers over that Bunsen burner.

Let's try another one.

Which apparatus supports and protects apparatus over a heat source, a, b, or c? Well done if you said a.

That is the gauze that does the supporting and protecting, and we said previously that b is a Bunsen burner and does the heating, and c is the tripod which elevates those larger mixing containers.

Okay, time for our first task.

What I'd like you to do is to complete these following sentences.

You may want to pause the video here and come back when you're ready to check your answers.

Let's see how you got on.

So if you completed them correctly, they should read as this.

a says, "Mass is measured in grammes," and you could have said lowercase g, which is the abbreviation for grammes, "using a balance." So, "mass is measured in grammes using a balance." For b it should be, "Volume is measured in centimetres cubed using a measuring cylinder or pipette." And that's quite easy to remember if you remember that the measuring cylinder is quite a narrow body and it would look kind of like a cylinder that we talk about in maths.

For this part of the task, what I'd like you to do is to put each apparatus into the correct column.

Is it being used for heating, or is it being used for measuring? And I've put two in each column so that you've got a starting point.

Pause the video here and come back when you're ready to check your answers.

Okay, let's see how you got on.

So in the first column of equipment for heating, hopefully you have put a Bunsen burner, a thermometer, and a tripod.

In equipment from measuring, you could have put a ruler, the balance, and the measuring cylinder.

If you put thermometer in the column for measuring, you would also be correct.

So well done if you managed to get those correct.

Now that we're feeling more confident talking about the equipment used for measuring and heating, let's look at the equipment that we might use for mixing.

If you were to look around any science lab, and that's maybe on a TV show or pictures on the internet, you might see lots of different pieces of equipment that could be used to mix different chemicals together.

We're gonna focus today's discussion on those that are used most commonly in a school science lab to create a mixture.

Now, when we're putting a mixture together, we are making something that has at least two different substances that are mixed together.

So it makes sense that we're gonna start then with our stirring rod.

A stirring rod tends to be a long thin stick-like apparatus and it's usually made of glass or plastic, and it does exactly as it says, it stirs or mixes two substances together.

The other equipment that you might use for mixing is the containers that those chemicals are being kept in.

So you could use a long thin tube, usually a test tube, or a boiling tube, you might upgrade that to a beaker, or you might use a conical flask, which looks like a beaker slightly, but it's shaped like a cone.

Because we have a few choices with the container that we're going to use when we create a mixture, we want to consider three main questions before we actually make that choice.

And the first thing that we're gonna do is think about the volumes that we're going to be using.

Is our container going to be large enough to hold the volumes that we want to be using? The second thing we might want to consider is do we need any additional equipment for that mixing to actually take place within that container? The last thing we wanna think about is once we've made our mixture, will we be able to easily pour it somewhere else if we need to? So let's have a closer look at those containers to decide which would be best going forward.

So if we start our discussion of equipment for mixing with the smallest container, that's our boiling tubes, and our test tubes.

Now these containers are very thin and they're small.

So what they do is they limit the volume that you can actually be mixing together.

So the test tube can hold roundabout 25 centimetres cubed, while the boiling tube could hold about 50 centimetres cubed in total.

That's not a very small mixture, but if your mixture is going to end with a reaction taking place, it does make that final reaction that's happening a lot safer.

Also, because these are narrow tubes, that means just like when we were looking at our measuring cylinder and our pipette, it's easier to make those simple observations, our observations might be a bit more accurate.

The other thing that we need to consider then with a test tube is that in order for the chemicals that we might want to mix together, actually mix, you'll probably need a stirring rod.

Because that container is so thin, you'll need the stirring rod to kind of force those two chemicals together.

Now another key feature of a boiling tube or a test tube is the fact that it has a rounded bottom.

That means that you're not gonna be able to stand a test tube or boiling tube up on the table.

You're gonna need something to hold it upright for you.

So that's when you use a test tube rack.

And we've got two examples here.

There's the wooden rack on the left and the metal Z-frame one on the right.

And they both do exactly the same job, they'll hold that test tube boiling tube upright for you.

The metal Z-frame one is actually quite handy though because it can hold multiple boiling tubes and test tubes.

So the boiling tube closest to you, the test tubes in that middle set of holes, but it also has those smaller set of holes, the far back that could hold pipettes.

So actually one of these types of test tube racks is really useful for organising your station if you're going to be using lots of these types of apparatus, boiling tubes, test tubes, and pipettes.

The next container that you might choose to use is a beaker.

And the great thing about beakers is that they come in lots of different sizes.

And what that does is allow for a lot of flexibility when you are choosing your mixing container in terms of the volumes that you might be using.

But if we look a little bit closer at beakers, there are other features we should need to be aware of.

The first one that we can see when we take a closer look is that it has a small spout.

That means that it can very easily pour contents once that mixture has been made.

It also has straight sides, so it's easy to grip, carry around, but it might need a stirring rod for actually mixing things similar to you might needing a wooden spoon to mix a cake batter in a bowl, okay? You're gonna need something to bring all those chemicals together.

And what we can also see here is that it has markings on the side.

Now, we said earlier that markings indicate a measuring apparatus, but here there means something slightly differently.

Because our beaker is actually quite wide, we're not gonna be using it for measuring.

Instead, those markings are used to help us gauge the volumes that might be able to be held within that container.

Because it's far less accurate than a measuring cylinder, those volumes are for reference points, not for measuring.

Now conical flasks, like beakers also come in a large variety of sizes and that again provides the flexibility of choosing the one that's going to fit the volumes that you might want to use.

Looking closer at a conical flask, we can see that it doesn't have a spout, so it would be far more difficult to pour a resultant mixture out of this container, okay? So not as easy to pour.

We can see though that it does have sloped sides rather than straight sides like our beaker, and that actually allows for mixing to occur a little bit more easily, and I'll get to that in a moment.

And finally we can see that just like with the beakers, it also has markings, and like with the beakers, those are simply used to help gauge the volume that you could be holding within that conical flask.

And it's not used for measuring because it's not a narrow container, it's far less accurate.

So we're just using it for a reference point again.

Now I said with the beakers and the conical flasks, they are very, very similar.

But one of the key features on deciding whether or not you might use a beaker or a conical flask is down to safety when you're actually mixing them together.

You can see here the beaker is being swirled so that we can try and mix the chemicals together without using a stirring rod.

And when that happens, some of the liquid actually splashes out both onto the table and onto the person's hand who's swirling that.

If we do the same action with the conical flask, look what happens.

The liquid stays within the container and that's due to the sloped sides.

The liquid moves up that slope side, but it gets to a point where it then falls back down into the container and it doesn't splash about.

And this allows for easy mixing without using any additional equipment.

Okay, time for a quick check to see how you're getting on with equipment for mixing.

Which of these pictures below shows a test tube? Well done if you chose c.

That is a test tube.

b shows a beaker and a, was actually our stirring rod.

Okay, let's try another one.

"Which of the following do you need to consider when choosing a container for mixing?" Is it, "The mass that will be used," "The volume that will be used," or, "The temperature of the mixture"? Well done if you said b, "The volume that will be used." Okay, let's do a task on our equipment for mixing.

What I'd like you to do is to match each of the apparatus to its correct name.

Take a moment, pause the video, and come back when you're ready to check your answers.

Okay, let's see how you got on.

So the tripod looks like this.

Tri meaning it has three bits to it, so it has three legs.

The test tube rack has the holes to hold those test tubes and boiling tubes upright.

Our gauze is that thin wire strip that helps to support the different containers over the Bunsen burner.

And then we have our dropping pipette.

Well done if you got those correct.

Now I've been saying through this whole lesson about the importance of choosing the appropriate piece of equipment.

So what I'd like you to do here is decide "Which of these apparatus would you use to easily observe small changes when mixing chemicals?" And once you've made your choice, I'd like you to justify your decision.

And the way to do that is usually to use a because clause.

Because what that will do is link up your thinking to your choice.

So have a think, pause the video, and come back when you're ready to check your work.

Let's see how you got on.

So if you chose the test tube, you'd be exactly right.

So well done.

Now, the way to justify your choice, there were a few different ways you could have gone about it.

So here are some options.

You might have said that, a test tube is narrow and that allows for easy observation of any small changes.

A beaker, for instance though, is too wide to observe those small changes easily.

And you could have also said something of the measuring cylinder being specifically designed for measuring volumes, not for observing reactions.

So well done on a tricky task.

But let's have a go at another one.

Okay, so we're gonna try another one.

This time I'd like you to decide which of these apparatus you would use to swirl together two liquids.

And like before, I'd like you to try to justify your answer, ideally using a because clause.

So have a think, pause the video, and come back when you're ready to check your answer.

Okay, let's see how you got on.

So to swirl two liquids together, the best piece of apparatus shown here would be the conical flask.

So well done if you chose that.

To justify your choice like before, there will have been several different ways you could have done that.

And your answer may have included something of the following.

If you focused on the conical flask, you could have said something about the fact that it has sloped sides, and that means that the contents won't splash out when you swirl that conical flask.

You could have said something along the lines that because the beaker has straight sides, that means if you were to swirl it, it would be unsafe, there would be splashing out potentially of any contents in it.

And you could have said that the test tube is far too narrow to allow for that quick and easy swirling to mix.

So well done if you managed to get that.

It was a tricky task.

So great job for having a go.

So let's go through what we've learned in today's lesson.

We've learned that equipment that's been designed for specific use is known as apparatus, and that the choices scientists make about which apparatus to use in their investigations can impact the quality of the results collected in their investigation.

We also learned that all matter has mass, and that mass is measured on a balance and in grammes.

And we also saw that all matter has volume, and that volume can be measured in a measuring cylinder or a pipette, or using a ruler, and that it is measured in the units of centimetres cubed.

I hope you had a good time learning with me today and to see you again soon.

Bye for now.