Lesson video

Hello everyone.

How are you today? I hope you're doing really well.

My name is Miss Afsal and I'm going to be your teacher for this lesson.

I'm very pleased about that because I think our topic is really interesting.

We're going to be looking at how scientists work.

That's the title of our lesson, "How Scientists Work," and it comes from the unit of work "Properties, Changes and Separating Materials." So I hope this sounds like an interesting topic to you and I hope you're feeling ready with some focus, energy and enthusiasm.

And if you are, we'll begin exploring our topic now.

The outcome for today's lesson is I can describe how some scientists control variables and why some scientists do not.

We have some keywords in our lesson.

Let's go through them one at a time.

My turn.

Your turn.

Variables.

Control variable.

Microorganism.

Antiseptic.

Astronomer.

Great to hear those words.

And now let's find out what do these keywords mean.

Variables.

A variable is something that can be changed, measured, or kept the same in a comparative or fair test.

Control variable.

Control variables are variables that are kept the same throughout an investigation.

A microorganism is a very tiny living thing.

An antiseptic is used to prevent the growth of microorganisms. And an astronomer is a scientist who observes objects in space.

Pause here and share with someone.

Had you heard of any of these keywords before? And if so, which ones? Thanks for sharing and don't worry whether you've heard of them or not.

They'll all be coming up in our lesson and we'll be learning more about them.

Our lesson is called "How Scientists Work," and it has three learning cycles: Material scientists control variables; Some variables cannot be controlled; and observing space.

Let's begin with material scientists control variables.

Andeep and Sam have been learning about materials and how they can be changed.

Here's Andeep, "I'm really interested in learning about materials." Love that attitude.

And Sam, "Me too.

I wonder what types of scientists work with materials." Pause here and share with someone.

Do you know what types of scientists work with materials? Thanks for sharing.

Here are Laura and Lucas.

Laura says, "Some scientists study what happens when materials change state.

Others help to develop new materials." Lucas, "A material scientist studies the properties of materials.

They carry out research and create or improve materials." Do you know of any other careers that could involve the study of materials? Pause here and share with someone.

Thanks for sharing.

Scientists who investigate materials often control, measure and change variables.

In a comparative or a fair test investigation, scientists only change one variable to observe or measure its effect on another variable.

This scientist studies the transparency of different materials.

This is a material scientist.

I can change the material and then measure the amount of light that passes through it.

All other variables must be controlled.

Control variables are variables that are kept the same throughout an investigation.

When investigating how transparent different materials are, I need to control variables such as the size and the thickness of the material, the brightness of the torch used and the distance of the torch from the material for each test.

Let's have a check for understanding.

Scientists who investigate materials will often control, measure and change.

Fill in the blank word at the end of this sentence with one of these three: A, variants; B, variables; C, varyings.

Pause here while you choose one of these words to complete the sentence.

Well done if you chose answer B, variables.

That's the correct answer.

Scientists who investigate materials will often control, measure and change variables.

Here's another material scientist.

"My question is: How does the volume of water affect the amount of sugar that can dissolve in it? In my investigation, I will only change one variable, the volume of water.

This will help me to find out the effect that only one variable has on the amount of sugar that dissolves." Important control variables for this investigation are: the type of sugar cube, the size of sugar cube, the number of sugar cubes, the size of the beaker, the material of the beaker, the temperature of the water, the temperature of the room, and the number of stirs.

So we must have the same amount of sugar and identical beakers containing different volumes of water.

Here's our material scientist again.

"By changing only one variable and making sure to control any others, I can be confident that the volume of water was the only variable that affected the amount of sugar that dissolved in it." Let's have a check for understanding.

What happens to control variables in an investigation? Is it: A, they are changed; B, they're not included; or C, they're kept the same? Pause here while you decide.

Well done if you selected answer C.

Indeed, what happens to control variables in an investigation is they are kept the same.

And now it's time for your first task.

Here's a question that a material scientist might ask: Which material melts at the highest temperature? For this comparative test investigation: One, which variable would you change; two, which variable would you measure; and three, which variables would you control? So pause here while you consider which variables will be changed, measured, and controlled for this comparative test investigation.

Pause here while you have a go at this task.

I'll see you when you're finished.

It's great to be back with you.

So, how did you get on with that task? So our question was, which material melts at the highest temperature? And you might have thought of these ideas: One, the variable I will change is the material; two, the variable I will measure is the temperature at which the material starts to melt; and three, the variables I will control will be the size and thickness of the material and the distance of the material from the heat source.

Well done for having a go at this task.

And now we're onto our next learning cycle: Some variables cannot be controlled.

Joseph Lister was a British surgeon and scientist who worked in the 19th century.

At that time, he was shocked to discover that a lot of people died after surgery.

Lister thought this might be due to infections from microorganisms. Microorganisms are very tiny living things like bacteria or fungi.

And here we can see some bacteria and some fungi.

Lister was interested in which variables affected the survival rate of patients after surgery.

He wanted to know if patients had a better chance of survival when medical staff involved in the surgery washed their hands to remove harmful microorganisms. Which variable would he change and which variable would he observe? Pause here and share with someone.

What do you think? Thanks for sharing.

The variable he would change is whether medical staff washed their hands.

The variable he would observe is the survival rate of patients.

And here's Joseph Lister.

"I would like to keep the same patient for each surgery, so I can observe if they survive depending on if the medical staff washed their hands or not." Would it be possible for Lister to control this variable each time? Pause here and show with someone.

What do you think? Thanks for sharing.

There are some types of investigations where some, but not all, variables can be controlled.

Lister would not have been able to repeat the same surgery on the same patient each time.

He would've had to use different patients who could have been men or women of different ages, heights, and health backgrounds.

Therefore, the patient was variable, he was not able to control in his investigation.

Let's have a check for understanding.

Which pupil is correct? Laura, "All variables must be controlled in every type of investigation." Or Lucas, "In some types of investigations, not all of the variables can be controlled." Pause here while you decide who is correct.

Laura or Lucas.

Well done if you selected Lucas.

Indeed, in some types of investigations, not all of the variables can be controlled.

Lister also investigated some other variables including whether cleaning the instruments used in surgery, the operating room and the patient's wounds after surgery affected the survival rate of patients.

Lister observed that washing hands and cleaning to remove harmful microorganisms improved the survival rate of patients.

And we can see there's some antiseptic spray there in that image.

Joseph Lister's findings led him to develop antiseptics.

Antiseptics prevent the growth of microorganisms. They're used to keep wounds clean.

Antiseptics are still used today to reduce the risk of infection and stop the spread of infectious diseases.

And we can see someone spraying some antiseptic spray there.

Perhaps you've seen or used antiseptic spray or gel.

Let's have a check for understanding.

Which scientists undertook scientific investigations that led to the development of antiseptics? Is it: A, Louis Pasteur; B, Joseph Lister; C, Dorothy Hodgkin; or D, Mary Curie? Pause here while you decide.

While done if you selected answer B, Joseph Lister.

Indeed, he is the scientist who undertook scientific investigations that led to the development of antiseptics.

Sarah Gilbert is a British scientist born in 1962.

She studies and develops vaccines to help prevent the spread of infectious diseases.

Gilbert's work resulted in the development of a COVID-19 vaccine in 2020.

Some of the variables that Gilbert may have controlled include: The ingredients in the vaccine; the amount of vaccine given.

And now we can see an image of the COVID-19 virus, which spread all around the world in 2020.

Let's have a check for understanding.

Sarah Gilbert's vaccine helped limit the spread of which of the following viruses: A, influenza (or flu for short); B, rhinovirus (or the common cold); C, COVID-19; or D, measles? Pause here while you decide.

Well done if you selected answer C, COVID-19.

Indeed, Sarah Gilbert's vaccine helped limit the spread of COVID-19.

And now it's time for your next task.

I would like you to think about the important work carried out by Sarah Gilbert to develop a COVID-19 vaccine.

As with Joseph Lister's investigations, Sarah Gilbert and her team could control some but not all, variables.

Why do you think Gilbert and her team were not able to control the variable: The patient who tested the vaccine? Talk to a partner about your ideas, Pause here while you do this.

It's good to be back with you.

So how did you get on with that task considering why you think Gilbert and her team were not able to control the variable: The patient who tested the vaccine? Let's take a look at an answer.

I think this is because each vaccine wouldn't be tested on the same patient.

The patients would be men or women of different ages, heights, and health backgrounds.

Well done if you came up with an answer like this.

And now it's time for our next learning cycle: Observing space.

An astronomer is a scientist who observes objects in space.

They learn more about how our universe works by making observations and looking for patterns in their data.

However, astronomers cannot control variables in space and we can see an astronomer there studying the night sky.

How fascinating.

Astronomers make measurements or observations to explore situations where there are variables they can't control.

As they can't control or change the variables they're studying, they answer questions by looking for possible links, patterns, or connections, using their observations.

Let's have a check for understanding.

True or false.

Astronomers are able to control variables.

Pause here while you decide.

Is this statement true or false? Well done if you selected false.

And now I'd like you to justify your answer by choosing from one of these two statements: Either A, astronomers make observations and look for patterns in their data, but cannot control variables in space; or B, astronomers cannot conduct any type of research because they cannot control variables in space.

Pause here while you decide which of these statements justifies your answer.

Well done if you selected statement A.

Indeed, astronomers make observations and look for patterns in their data but cannot control variables in space.

Nicolaus Copernicus was born in 1473 in Poland.

He was the first astronomer to suggest that the sun is the center of our universe.

Until his work, other scientists like Aristotle had thought that Earth was the center of the universe and that the sun and other planets orbit Earth.

Now we can see a diagram of the solar system.

Copernicus made observations of the planets to see how they moved in the sky.

He used a telescope for his observations and mathematical calculations to help him explain what he observed.

His observations provided evidence to support his idea that the sun is at the center of the universe.

Maggie Aderin-Pocock is a British space scientist, born in 1968.

She designs and builds instruments that are carried on satellites in space.

She uses these instruments to make scientific observations and we can see a satellite in space there.

Perhaps it's carrying one of Maggie Aderin-Pocock's designs.

As a space scientist, Aderin-Pocock tries to learn about our universe and helps other people understand it.

The work of astronomers helps us understand how planets, including Earth, formed and are developing.

Aderin-Pocock's work in particular helps us understand Earth's climate and track climate change.

Let's have a check for understanding.

How does the space scientist Maggie Aderin-Pocock make her observations? Is it: A, using instruments on microscopes in space; B, using instruments on satellites in space; or C, using instruments on rockets in space? Pause here while you decide.

Well done if you selected answer B.

Indeed, the space scientist, Maggie Aderin-Pocock makes her observations using instruments on satellites in space.

And now it's time for your next task.

Here's a question an astronomer might ask: Does the size of an asteroid affect the size of the crater it makes on the moon? Which variables would an astronomer not be able to control to answer this question? Pause here while you consider this and I'll see you when you've had that discussion.

It's great to be back with you.

So how did you get on with that task and having that discussion about which variables an astronomer would not be able to control to answer this question: Does the size of an asteroid affect the size of the crate makes on the moon? Your answer may have included some of these ideas: Astronomers cannot predict exactly when asteroids will be close enough to hit the moon or which part of the moon they will hit.

They cannot control the size or mass of the asteroids or what they're made of.

They also cannot control how fast the asteroids will hit the moon or how they might break apart during a collision.

This is why astronomers rely on their observations of space to answer questions.

Well done if you came up with some answers like these.

In our lesson, "How Scientists Work," we've covered the following: Scientists who investigate materials often control, measure, and change variables; control variables are variables that are kept the same throughout an investigation; there are some types of investigations where some, but not all variables can be controlled; astronomers make observations and look for patterns in their data, however, they cannot control variables in space.

Well done everyone for joining in this lesson.

It was so great to explore how scientists work, what variables are, which variables they can control, which ones cannot be controlled.

And also, I thought it was particularly fascinating to explore how astronomers make observations, which variables they can or mostly cannot control.

I hope you've enjoyed this lesson.

I've certainly enjoyed teaching you, and I'm looking forward to seeing you at another lesson soon.

Until then, stay curious.