Hello, my name's Mrs. Hart, and I'm really excited to be learning some science with you today.

I can't wait to get going with this lesson.

So let's get started.

Welcome to today's lesson from the unit materials.

This lesson is called the effect of adding salt to ice, do and review.

And by the end of today's lesson, you're going to be able to carry out and review an investigation into the effect of adding salt to ice.

This lesson links back to some previous learning where we've planned an investigation into the effect of adding salt to ice.

But don't worry if you haven't completed that lesson.

Everything you need is in this lesson too.

Some of the learning in today's lesson might be new to you, but I'm here to help, and we're going to have a lot of fun along the way.

Here are the key words for today's lesson.

Some of these might be new to you or perhaps you've seen them before.

If you need to refer to them later, they're here on this slide, but I'll explain the words as we come across them in the lesson.

Our first key word is rock salt.

Then melt, equipment, conclusion, and review.

And now I think we're ready to begin our lesson.

Today's lesson is in two parts.

The first part of the lesson is called using salt to melt ice.

The second part of the lesson is called reviewing an investigation.

But for now, we're ready to start with the first part, using salt to melt ice.

Izzy and Jun have been learning about different types of salt.

"I have learned that table salt is often used on food to give it extra flavour." Perhaps you use table salt on your food sometimes, or you know someone in your family who does.

Jun says, "I've learned that rock salt is often used to melt ice on roads and pavements." And you might remember that rock salt is salt in its unprocessed form, and when we melt something, it will go from a solid state to a liquid state.

Yellow bins containing rock salt, also known as grit, are provided by local councils so that if a gritter cannot clear your road, you can safely do so yourself.

I have learned that you cannot take grit from a grip bin if you're using it to melt ice on private properties such as driveways.

So you might have seen these grip bins in the town where you live or perhaps near to your school.

So you can use these on the roads and pavements that the public use, but you cannot take the grit to use on your own private property, perhaps if you have a driveway or a path outside your home.

And now we've got our first check for understanding.

What is rock salt often used for on roads and pavements? Is it A, to freeze ice, B to freeze water, C to melt ice, or D to melt water? Pause the video now and have a think or talk to your partner, and come back when you've worked out your answer.

So what did you decide? What is rock salt often used for? It's to melt ice, and well done if that's what you said too.

When rock salt is used in icy conditions, it causes the ice to melt, to go from that solid state to a liquid state, and it helps to prevent further ice from forming.

And in this image, we can see some rock salt has been added to some ice.

And here, we can see the effects after 15 minutes.

And if you look closely around the rock salt, you can see that the ice has begun to melt and has become water in its liquid state.

Frozen water or ice, normally melts at zero degrees Celsius.

Adding salt lowers the melting temperature, so the temperature at which frozen water melts.

This speeds up the rate of melting.

Water on roads treated with rock salt might not freeze until the temperature drops to minus five degrees Celsius, helping to prevent new ice from forming.

Here we can see an image of rock salt on ice, and when it's added to the ice, it will lower the melting temperature.

Here's our next check for understanding.

What happens when we add salt to frozen water, which is also known as ice? A, it lowers the melting temperature.

B, it raises the melting temperature.

C, it slows down the rate of melting.

And D, it speeds up the rate of melting.

So it's now time to pause the video and to discuss this, and to come back when you've worked out your answer.

So what did you decide for this question? What happens when we add salt to frozen water, ice? Well, two things will happen.

It lowers the melting temperature.

Do you remember we said it would lower it from zero degrees Celsius to minus five degrees Celsius? And it also speeds up the rate of melting due to that lower melting temperature.

So well done if that's what you said too.

Izzy and Jun have planned their own investigation to compare how long it takes ice to melt when different types of salt are added.

"Our question is which type of salt melts the ice the fastest, rock salt or table salt?" Jun says, "We will sprinkle 30 grammes of rock salt over four ice cubes and then measure how much ice has melted after 10 minutes.

We will do the same with table salt." What equipment will they need? Pause the video now and have a talk to a partner or in your class about the equipment that Izzy and Jun will need to answer their question.

What different types of equipment did you think of for this? Well, equipment is any object or materials used to collect data in a science investigation.

Scientists use a range of equipment to observe, measure, and compare when they investigate to find answers to questions.

What equipment have you used to investigate in science lessons? And here we can see a scientist investigating using tweezers.

Pause the video now and discuss with a partner the equipment that you have used to investigate in your science lessons.

Well, what did you say? There are so many different types of equipment that you could have used.

Let's have a look and see the equipment that Izzy and Jun have decided to use for their investigation.

Here is some of the equipment that Izzy and Jun plan to use for their investigation, and here's a diagram, and we can see it's showing the ice cubes and the different types of salt.

Can you identify and name the equipment in their diagram? They're going to use two funnels, one for each type of salt, and two beakers.

And well done if that's what you said too.

Is this what you thought Izzy and Jun might use for their investigation? Or perhaps you had a different idea.

What pieces of equipment will Izzy and Jun need to measure 30 grammes of each type of salt and 10 minutes of time.

Again, you might like to pause the video here so you can discuss this.

Well, Izzy and Jun are going to need two different pieces of equipment to measure these things.

They're going to need some scales, like the digital scales in this picture, to measure the 30 grammes of salt.

And they're also going to need a stopwatch to measure the 10 minutes.

You might have a stopwatch like this or perhaps you have one on a tablet that you could use instead.

And well done if that's what you said.

Here's our next check for understanding.

Which of these pieces of equipment is a funnel, A, B, or C? Pause the video now, discuss this with your partner, and come back when you know which one of these is a funnel.

So what did you decide? Well done if you said B.

B is a funnel.

This is where Izzy and Jun plan to place their ice cubes.

The other equipment in this check for understanding was a pipette and some filter paper, but these are not pieces of equipment that Izzy and Jun plan to use today, but maybe they'll use them in a different investigation.

Izzy and Jun discuss the variables that they will change and measure in their investigation.

You might remember that variables can be changed, measured, or kept the same.

"The only variable we will change is the type of salt." "The variable we will measure is the amount of ice melted after 10 minutes." So this is the ice that has melted into the liquid state of water.

What equipment will they use to measure the amount of ice that has melted? Pause the video now, have a discussion with a partner, and come back when you've worked out your answer.

Izzy says, "Ice is water in the solid state.

It will melt and change state to liquid water.

This water will drip down through the funnel and into the beaker below.

We will leave the ice to melt for 10 minutes." Here you can see where the ice has melted and changed state to liquid water.

It's dripped down into the bottom of this beaker.

"When we have left the ice to melt for 10 minutes, we will pour the water we have collected into a measuring cylinder, so that we can accurately measure the volume of water." And here is Jun pouring that water into a measuring cylinder.

Pouring the water into a measuring cylinder allows us to measure the amount of water accurately.

"When we use this equipment, we need to try and control variables too." "Apart from the type of salt, we will keep other variables the same, including the number and size of ice cubes, the mass of salt, and the temperature of the room." Izzy and Jun have said it might be tricky to control the size of the ice cubes, but they're going to choose ice cubes that look as though they are the same size.

And here's our next check for understanding.

Which piece of equipment do scientists use to accurately measure the volume of water? Is it A, a beaker, B, digital scales, or C, a measuring cylinder? Pause the video, talk to your partner, and come back when you know which piece of equipment scientists use to accurately measure the volume of water.

How did you get on? Well, I'm hoping that you said C, a measuring cylinder, Izzy and Jun plan to pour the liquid water from the beaker into the measuring cylinder, so that they can accurately measure how much of the ice has melted.

Well done if that's what you said.

And now we have task A.

Using your own plan, carry out an investigation to answer the question, which type of salt melts ice the fastest, rock salt or table salt? You might record your results in a table like this.

You can see this has three headings, type of salt, volume of water collected after 10 minutes measured in millilitres, and any other observations that you make.

You can use your own plan, or if you don't have your own plan, then you can use the ideas that we've shown you in this lesson so far.

So now it's time for you to go and be scientists and to investigate which type of salt melts ice the fastest, rock salt or table salt.

I can't wait to see what you find out, and I'll see you back here when you've completed your investigation.

How did you get on? Sounds like you've been very busy.

Let's have a look, shall we? So you were using your own plan or you could use the ideas in our lesson if you didn't have your own plan, and you were carrying out your investigation to answer this question.

Which type of salt melts ice the fastest, rock salt or table salt? This is what we did.

I put four ice cubes into a funnel and placed the funnel over a measuring cylinder.

I then added one teaspoon of table salt to the ice cubes and measured how much ice had melted in 10 minutes.

I will repeat this again using four more ice cubes and a teaspoon of rock salt.

Did you do something similar or perhaps yours was a little different to how we'd done it? Did you record your results in a table like Izzy and Jun's? Hopefully you recorded each type of salt and the volume of water that had collected after 10 minutes.

You may have made some extra observations like Izzy and Jun have here.

Let's find out some more, shall we? The second part of our lesson is called reviewing an investigation.

So here are the results of Izzy and Jun's investigation.

They've put them in a table.

Does your table look like this one? They've got the type of salt, the volume of water collected after 10 minutes in millilitres, and other observations.

And this is what they've recorded.

So rock salt.

They collected eight millilitres of water after 10 minutes, and they observed rock salt stayed on top of the ice cubes.

Ice cubes melted more slowly to start with, then started melting more quickly.

And the second part of the table, the type of salt is table salt.

And the volume of water that they collected after 10 minutes was 10 millilitres, and they observed some table salt dropped through the funnel into the measuring beaker.

The ice started to melt immediately.

Did you observe something similar to this? What do their results show? Pause the video now and discuss with your partner or class what these results show us.

Which type of salt melted the ice more quickly? Come back when you've had a chance to talk about it.

So what did you notice about their results? Perhaps you observed that the table salt had melted more of the ice in the 10 minutes.

Perhaps you discussed the fact that some of the table salt dropped through the funnel and into the measuring beaker beneath.

Maybe you talked about something different.

Let's find out some more.

The results of an investigation are used to make conclusions.

In a conclusion, scientists explain what the results show or mean.

The question that Izzy and Jun were investigating is which type of salt melts ice the fastest, rock salt or table salt? So to do this, scientists need to make sense of their findings and they need to answer their inquiry question.

The children use the results of their investigation to make conclusions.

"My conclusion is that table salt melts iced faster than rock salt does." "I wonder why our grit bins are not full of table salt if it's more efficient than rock salt for melting ice.

I would like to include this in my conclusion too." Do you have any ideas why? Pause the video now and have a discussion around this, and come back when you have some answers.

Rock salt is extremely useful for melting ice, however, it is not as efficient as table salt.

Let's find out some more from a highway supervisor.

He's an expert that can help us.

He says, "The reason we use rock salt instead of table salt for melting ice on roads and pathways is that rock salt is much cheaper to supply in large amounts than table salt." Rock salt contains some sand, and this, along with the larger granules of salt, mean that rock salt helps to increase road surface friction for car tyres in icy conditions.

So did you say something like this? Did you wonder if perhaps table salt was more expensive than rock salt? Perhaps you thought about the granules and the textures of the different salts and the fact that cars will need friction to drive safely in icy conditions.

Perhaps you said something different.

Here's our next check for understanding.

Who do you agree with? Aisha says, "The results of an investigation are used to make a question." Alex says, "The results of an investigation are used to make a conclusion." Sophia says, "The results of an investigation are used to make a prediction." Who do you agree with? Pause the video, discuss this with a friend, and come back when you have an answer.

Well, who did you agree with? The results of an investigation are used to make a conclusion.

So well done if you said Alex was correct.

Izzy and Jun have made their conclusion and begin to review their investigation.

When scientists review an investigation, they look again at what they've done and consider how it could be improved.

"I've been thinking about our investigation and I have some ideas for what we could do differently if we did it again." "Yes, it is important to review an investigation, to look again at what we have done and consider if it could be improved." Do you have any ideas? How would you review your investigation? Pause the video now and discuss this with a partner.

Izzy says, "I observed that when we added the table salt to the ice cubes, some of the salt dropped through the funnel and into the measuring beaker.

We should think of a way to keep the table salt on top of the ice." It's an interesting point, Izzy.

Did you notice and observe that when you did your investigation? Jun says, "In my review, I will suggest that we use crushed ice instead of ice cubes so the table salt cannot fall through so easily." That's an interesting suggestion, Jun.

Would you try something like that too? "I wonder if ice melts at the same rate without any salt added to it.

It would be interesting to measure how much ice melts in 10 minutes when no salt has been added." Did you say something like that? "In my review, I will suggest that we set up another test to compare how fast ice melts without salt.

It would also be fascinating to test ice with other substances such as flour and sugar." Did you think of something like that? Perhaps there were other substances that we could test to see how they affect the rate at which the ice melts.

How could they do this? Pause the video now and have a discussion with a partner.

Well, I think that they would need to repeat their investigation using that same equipment, controlling the same variables, but instead of different types of salt, they could try using different substances such as flour and sugar.

This would then be interesting to see how quickly the ice melts when we use these things as well.

Izzy says, "We only did our test once.

I wonder if all the other pupils in the class found that table salt helped to melt ice faster than rock salt." Did you find that? Were there differences in the results in your class? Jun says, "In my review, I will suggest that we repeat our tests three times to check our results.

It would also be interesting to ask the other pupils in the class what they found in their tests." How could they do this? Pause the video now to discuss how they could do this.

How did you get on? Well, they could share their results within the class.

Perhaps this is something that you've done.

Did everyone have the same results as you? Or perhaps there were differences in the results? Have you wondered why there might be differences in the results? They could repeat the test three more times to check their results and begin to see patterns that emerge.

Perhaps you could do this too.

Here's our check for understanding.

When scientists review an investigation, they, A, do the investigation again, B, look again at what they have done, C, tidy away the equipment they have used, D, consider how the investigation could be improved.

Pause the video now, discuss this with your partner, and come back when you've worked out your answer.

What did you say? When scientists review an investigation, they look again at what they have done and consider how the investigation could be improved.

Well done if that's what you said as well.

Here's our second task of this lesson.

This task is in two parts.

For the first part, I would like you to use the results of your investigation and write a conclusion to explain what your results show or mean.

If you haven't got your own results for your investigation, then you can use the ones that we've provided for you here.

So pause the video now, and it's time for you to write a conclusion explaining what your results show or mean.

Here's a conclusion that we've written.

Your conclusion might be similar or perhaps different to this.

Let's find out.

In 10 minutes, more water was collected from the ice melted with table salt, 10 millilitres, than from the ice melted with rock salt, eight millilitres.

I think that the table salt would be a more efficient way of melting ice on pavements and roads, but it is more expensive than rock salt.

Rock salt is stored in grit bins and used by gritters to melt ice, rather than table salt, because it is cheaper, and the larger granules and the sand provide friction for road vehicles.

Was your conclusion similar to this? Perhaps it included some more detail.

Well, well done.

The second part of our task is to review your investigation.

And Jun's reminding us here that when we review an investigation, we look again at what we have done and consider if it can be improved.

So how would you improve your investigation? Have a think about the ideas that we've discussed in this lesson.

You might have some similar ideas or perhaps you have something different in mind.

So review your investigation, pause the video now, and come back when you've done that.

So now you've had the chance to review your investigation.

Izzy decided that, "During the test, do not pick the funnel up and move it around to help the ice to melt more quickly." Did anyone in your group try this? That's a great suggestion, Izzy.

Jun says, "Keep the funnel resting on the beaker.

Don't pick it up, because the heat from your body could affect the rate at which the ice melts." Did you suggest any other improvements? What kind of things did you say? Well, now we've come to the end of our lesson, and let's just have a recap of the things that we've learned today.

We have learned that rock salt is often used to melt the ice on roads and pavements.

Adding salt to ice lowers the melting temperature of ice and speeds up the rate of melting.

Scientists use a range of equipment to observe, measure and compare.

The results of an investigation are used to make conclusions.

When scientists review an investigation, they look again at what they have done and consider if it could be improved.

Well, I hope you've enjoyed our lesson today.

Perhaps you're going to try the investigation again.

We were going to test some different substances.

Well, I hope you enjoyed it and I'll see you again soon.

Bye.