Welcome to today's lesson on comparing fuels.

It's part of the fuels and energetics topic.

My name is Mrs. Mytum-Smithson, and I'm so pleased that you've come along to learn with me today.

During this lesson, we're going to be looking at comparing fuels.

Don't worry if you don't know anything about fuels or how to compare them, because by the end of this lesson, you should be able to carry out a fair test to compare the energy transferred by burning different fuels.

Today's keywords are combustion, fair test, control variables, fuel.

On the next slide, there's some sentences that include these keywords.

So if you wish to read them, pause the lesson, and then press play when you're ready to learn.

This lesson consists of two learning cycles.

First, we're going to learn about burning fuels, and then we'll learn about how to compare fuels.

So let's get going now with burning fuels.

Burning a fuel is a chemical reaction with oxygen called combustion, and that produces new products.

Here's something called a spirit burner, and a spirit burner is made of glass.

And inside of that we put a fuel, that's the chemical energy store.

For example, we might put alcohol in there.

We've got a wick like the one you would find in a candle, and on top of that, we have the flame.

Now energy cannot simply be released from a fuel.

Energy is transferred from the burning fuel, that's the chemical energy store, to the surroundings, that's the thermal energy store, by heating.

So if we have a look here, that is the energy being transferred from the burning fuel.

That's the thermal energy store.

And that warms the surroundings by heating.

I've got a quick check for understanding for you.

True or false.

Burning a fuel transfers energy from the surroundings to the fuel by heating.

Is that true or is that false? Pause the video for some thinking time, and then press play when you want the answer.

Well done if you said that that was false, and now I want you to justify your answer.

So you've got energy transfers from where it is warmer to where it is cooler by heating, or energy transfers from where it is cooler to where it is warmer by heating.

So pause the video now, have some thinking time, and then press play when you've got your answer.

Well done if you said that energy transfers from where it is warmer to where it is cooler by heating.

So it's always from the warmer part to the cooler part by heating.

Well done if you got that right.

Some examples of everyday fuels include coal, gas, petrol, diesel, charcoal, wood.

Here's some charcoal being burned on a barbecue.

And you can see here, the energy is released during the chemical reaction, and that is transferred from the burning charcoal to the surroundings.

That's the air.

Here's a quick check for understanding.

I want you to select all the fuels from the following.

So you've got a choice of fire, coal, petrol, smoke.

Pause the video for some thinking time, and press play when you've got your answer.

So, well done if you spotted that coal and petrol fuels.

The students are discussing burning fuels.

Who do you agree with, who do you disagree with? Explain why.

So Andeep is saying, "Burning destroys the energy that is stored in the fuel." Jacob is saying, "When a fuel burns, energy is transferred to the surroundings." Laura says, "Burning makes energy." And Sam says, "The energy in the fuel is used up when it burns." So pause the video, and then press play and we'll go through the answers.

Well done if you said Jacob.

When a fuel burns, the energy is transferred to the surroundings.

So that chemical reaction takes place from the fuel, and that energy is transferred to the surroundings from that chemical store in the fuel by heating.

Andeep had said, "Burning destroys the energy that is stored in the fuel," and you cannot destroy energy.

Just like Laura says, "Burning makes energy." You cannot make energy.

And the energy in the fuel is used up when it burns, you cannot say that energy is used up.

Energy has to go somewhere because energy is never destroyed.

It's only transferred from one store to another store.

So, well done if you agreed with Jacob.

Here's task A.

What I want you to do is draw a diagram of a lit candle, and I want you to label up the fuel, and I want you to name that fuel.

I want you to label up the chemical energy store, the thermal energy store, and add arrows to show the direction of energy transfers.

And then for part two of task A, I want you to name as many everyday fuels as you can.

So pause the video whilst you complete that task, and press play and we'll go through the answers together.

Well done for completing that task.

Let's go through the answers.

So here's our candle, and we should have labelled up the fuel, which is the candle wax, the wick, and the flame.

Then we've got some arrows going from the flame to the surroundings, and we've got the chemical energy store.

We've got that one labelled up, and the thermal energy store.

So, well done if you've got that one correct.

And then for your fuels, you could have had any from this list, and perhaps some other named fuels.

So coal, gas, petrol, diesel, charcoal, wood, wax, and any others that your teacher says are correct.

So, well done for working hard and doing that task.

Now we've completed this first learning cycle.

We're going to look at comparing fuels.

In order to compare different fuels, we can carry out an experiment to measure their energy transfer.

So we can burn the fuel, let that fuel heat up some water, and then measure the temperature change.

So in order to do this, here's our equipment that we've got set up.

So we've got a heat resistant mat, a clamp and a clamp stand.

In that clamp is a boiling tube, and it's got some water in there with a thermometer placed inside of that.

And then we've got the next part which is the fuel.

And we've got a metal bottle cap to keep it contained in.

And then we've got a flame showing that we are burning the fuel.

When we carry out any science experiment, we're going to look at variables.

So we've got three variables to look at.

The independent variable is the variable that we choose to change.

The dependent variable is the outcome that we measure.

So whatever results we're looking for, that's the dependent variable.

And the control variables are the variables in that experiment that we keep the same to make it a fair test.

So in this case, we've got a little table here now.

We're going to look at the independent variable.

Remember, that's the one that we've chosen to change.

So we're going to look at the fuel type.

So we're going to look at different fuels.

The dependent variables, so this is what we're going to measure the outcome, and that's going to be the temperature change of the water.

And to make it a fair test, we're going to keep the same, the mass of the fuel and the volume of the water.

Let's have a look in more detail at the method that we're going to carry out.

So here's our equipment setup as we've gone through in the previous slide.

The first thing you're going to do is add one gramme of fuel to the metal bottle cap.

So you're going to need to put that onto a balance.

You're going to measure 25 centimetre cubes of water using a measuring cylinder.

You're going to add the water to the boiling tube.

You're going to measure and record the initial temperature of that water.

Then you're going to light the fuel and let it completely burn.

Then you're going to measure and record the highest temperature that the water reaches.

A quick check for understanding now.

When should you measure and record the temperature of the water in the boiling tube during the experiment? Should you only measure and record the temperature at the start of the experiment? Should you measure and record the temperature at the start of the experiment and the highest temperature reached? Should you only measure and record the highest temperature reached? Or should you measure and record the temperature every minute for 10 minutes? So pause this video, choose your answer and press play, and I'll tell you if you're right or not.

So, well done if you said B.

You need to measure and record the temperature at the start of the experiment and the highest temperature reached.

The volume of water being heated needs to be the same for each experiment to make it a fair test.

So here, you can see different volumes of water, and if the volume of water was not the same, then it would be unfair, because the boiling tube that's got a lot of water in would not heat up as much as the one that's only got a little bit of water in.

So in order for us to measure the volume of the water, we are going to be using a measuring cylinder to do that.

So the volume of water is a variable, and we control that variable by using a measuring cylinder.

That makes it a fair test.

The massive fuel used in each experiment needs to be the same to make it a fair test.

This is called a control variable.

So here, you can see we've got the bottle caps there.

We've got the fuels in them.

And on the balances there, you can see that one's got one gramme and one's got 1.

25 grammes.

So we would not be able to compare these fuels if they've got a different mass.

It would not be a fair test.

What I want you to do for this check for understanding is select the image that shows the setup of the second experiment you should carry out when comparing two fuels using a fair test.

So the first experiment used 25 centimetre cubes of water and one gramme of fuel A.

I want you to select which image shows the setup of the second experiment you should carry out, making sure that it's a fair test.

So pause the video, select your image, then press play and we'll go through the answer.

Well done if you said it was B.

You need to have the same volume of water and the same mass of fuel.

So you need to have one gramme of fuel B and 25 centimetre cubed of water.

That is the same as when we carried out the experiment using fuel A.

Well done if you got that correct.

True or false.

We can use different masses of fuels when comparing the energy released during combustion.

Is that true or is that false? Pause the video and have a little think.

When you've got your answer, press play.

Well done if you said that that was false.

Now on to justification.

The mass of the fuel is a control variable.

The mass of the fuel is the independent variable.

Pause the video, have a think, and then press play and we'll go through the answer.

Well done if you said A.

The mass of the fuel is a control variable, it needs to be kept the same to make sure that it is a fair test.

Well done if you got that correct.

What I want you to do now is write a numbered method for the experiment using the images below to help you.

Put as much detail in, and you can see that some things have been circled so you need to mention those, and then pause the video whilst you do this, and then press play when you've completed the task.

Well done for completing that task.

Your answer might include, place the metal bottle top on the balance and zero the balance.

Add one gramme of fuel A to the metal bottle top.

Measure 25 centimetre cubed of water using a measuring cylinder, and pour into the boiling tube.

Measure and record the starting temperature of the water.

Light fuel A.

When fuel A is totally burned, measure and record the temperature of the water.

Finally, repeat the experiment three times using fuels B, C, and D.

So, well done if your answer looks similar to mine.

For task two, what I'd like you to do is complete the practical and fill in the results table.

Pause the video whilst you do this, then press play when you've completed the practical.

Well done for completing the practical and filling in your results table.

You should have been able to calculate the temperature change by taking the highest temperature reached and then subtracting the temperature at the start.

Now your results will vary depending on which fuels you use.

The fuel that has the largest temperature change transfers the greatest quantity of energy when undergoing combustion.

Here's part three of task B.

In a further experiment to compare the energy transfer over a set period of time, different fuels contained in spirit burners were burned.

So here's the setup you've used.

You can see that we've just substituted the metal bottle cap with the fuel for the spirit burner.

Five different fuels were burned for two minutes each.

The temperature of the water was measured before and after each fuel was burned.

What I want you to do is write down the independent variable, the dependent variable, and two control variables, and how you would control them for this experiment.

So pause the video while you complete that, and then press play, and we'll go through the answers together.

Well done for completing the task.

You might have chosen to put the variables in a table like mine, or you might have just written them in sentences.

Each is fine.

So let's have a look.

So the independent variable was the fuel type or the different fuels.

The dependent variable was the temperature change of water.

The control variable was the volume of water, and we did that by using a measuring cylinder.

Then we looked at the time that the fuel was burned and we used a stop clock in order to control that variable.

And fresh water each time, we change the water each time.

So, well done if you've got all of those correct.

Here's part four of task B.

This is the last task you're going to be doing today.

Here are the results from the spirit burner experiment.

What I want you to do is calculate the temperature change for each fuel type.

And then part five is write a conclusion and one improvement that could be made for this experiment.

So there's a sentence starter there for your conclusion.

And then I want you to also add in one improvement that you think could be made for this experiment.

Pause the video while you complete the tasks, and then press play and we'll look at the answers together.

So when we're calculating temperature change, remember, we just take the highest temperature reached, and we subtract from that the temperature at the start.

So this one was 21.

6 degrees.

Ethanol, we take 58.

6 subtract 30.

3.

We get 28.

3.

Propan-1-ol, 33.

9.

Pentan-1-ol is going to be 35.

3.

So here's your conclusion.

The fuel which transferred the most energy was pentan-1-ol, and that was because the temperature change was the greatest.

Well done if you got that correct.

An improvement would have been to measure the mass of the fuel burned.

And then we could calculate the temperature change per gramme of fuel, and that would provide a better comparison to the best fuel at transferring energy.

So, well done if you've got something like that.

Here's the summary for today's lesson.

Burning a fuel transfers energy by heating its surroundings.

Heating water in a boiling tube allows the energy transfer of different fuels to be compared.

The mass of fuel used needs to be the same for each measurement.

The same volume of fresh water being heated needs to be the same for each measurement.

The starting and highest temperature reached needs to be recorded in order to calculate the temperature change.

Well done for working really hard throughout this lesson.

I hope you're now much more confident in being able to compare fuels and carry out an experiment to do so.

I hope you come back and see me sometime soon for another lesson.