Hello, my name is Mrs. Mehrin and I'm so excited to be learning all about melting temperatures.

And today we are going to be doing, and reviewing.

Let's begin.

Welcome to today's lesson from the unit, introduction to states of matter and changing states.

Your learning outcome is, I can investigate the melting temperatures of common materials and evaluate my investigation.

Today we are going to be revisiting some of your learning from the previous two lessons about melting temperatures.

Now, I know that learning can sometimes be a little bit challenging, but that's okay, because it just means that we are going to work really hard together and we're going to learn fabulous new things.

Let's begin.

So here are your keywords for today's lesson.

Now, I am going to be referring to these keywords throughout today's lesson.

However, if you find it helpful, you can pause the video here, and you can jot these down.

Off you go.

Fantastic.

Well done.

So, our lesson today is split into two parts.

Let's begin with the first part, investigating melting temperatures.

So Andeep and Laura are observing chocolate buttons melting on Laura's hand.

And Laura says, "My hand must be warmer than the melting temperature for chocolate." Now the melting temperature of material is the temperature at which it changes from a solid state to a liquid state.

In the previous two lessons, we have touched upon this already, so you may already remember this from then.

Now, scientists ask questions, and investigate to find answers.

And here we have a picture of a scientist carrying out an investigation.

Now, Laura and Andeep have decided to carry out a comparative test investigation to answer their inquiry question, at what temperature do different materials melt? Okay, so before we continue with our learning today, let's see what you have remembered from the previous two lessons and also today's.

So the melting temperature is the temperature at which a liquid changes to a gas, a solid changes to a liquid, or a liquid changes to a solid.

I'll give you five seconds to think about your answer.

Off you go.

Fantastic, well done.

The answer is B, a solid changes to a liquid.

And that is what the melting temperature is, when a solid changes to a liquid.

Now the children will ask their teacher to prepare some water baths at different temperatures, and they're going to float small pie dishes in the water and put a different material in each pie dish.

Now, you need to be really careful with this and you need to ask an adult for help, because we don't want any of the hot water to spill because it could burn you, or it could harm other people as well.

So making sure that you've got an adult to help.

Now, Laura and Andeep's plan is to ask an adult to prepare a cold water bath, just like in this picture here.

They're going to put half a teaspoon of each material into its own foil pie case.

Now this is really important to measure this, so that this investigation is fair, and that they are getting an accurate result.

They're going to float the pie cases on the surface of the water, and they're going to observe it for five minutes to see if any materials begin to melt, so they could use a stopwatch for this.

They're going to measure and record the temperature of the water, as well as which materials melt.

And then they're going to repeat steps one to five with a warm water bath, and then a hot water bath.

Now, it is important for them to ensure that the level of water is also the same.

So Laura says, "We will need to take accurate measurements when we carry out our investigation." Scientists take accurate measurements of temperature using a thermometer in units of degrees Celsius.

And this thermometer here has a reading of 37 degrees Celsius.

So the children are going to record their results in a table like this.

So material A in cold water, does it melt? No.

Material B? No.

Does it melt in warm water? No.

Material B does.

And they're going to do it in a table like this, and they're going to record the temperature of the water and whether the material melts, yes or no.

Okay, before we continue, let's do a quick checking of your learning.

So what are thermometers used to measure and monitor? Is it A, sound, B, temperature, C, brightness, or D, noise.

I'll give you five seconds to think about your answer.

Off you go.

Fantastic.

Well done.

The answer is temperature.

Now scientists take accurate measurements of temperature in units of degrees kilogramme, degrees Celsius, or degrees litre.

So think back to your previous learning as well in the last two lessons, as well as what you have learned this lesson.

So I'm going to give you five seconds to think about your answer.

Off you go.

Fantastic, well done.

The answer is B, degrees Celsius.

So here is your first activity.

It says, carry out a comparative test investigation to answer the inquiry question.

At what temperatures do different materials melt? So here you can use your own plan, or you can use Laura and Andeep's plan.

So if you joined us for the previous lesson, we created a plan.

However, if you didn't do the previous lesson, that's okay, you can still use Laura and Andeep's plan.

You're going to record your results in a table, and an example is shown on this following slide here.

So you could record your results in a table like this, or one of your own design, so you don't have to do it like this.

So I'd like you to pause the video here and have a go at doing this.

Remember, Laura and Andeep's plan are on the previous slides to this, so you can rewind the video if you are using their plan.

Okay, off you go.

Fantastic.

Well done.

So did your results look like these? Now remember, you might have had different results, because you may have been investigating different materials.

It might not have been these ones.

However, remember you were to write yes or no depending on when the melting temperature would be.

So we can see here that cheese does not melt in any of the three water temperatures that Laura and Andeep chose.

Butter didn't melt in the cold water, but it did melt in the warm water and hot water.

Kitchen foil didn't melt at all.

Ice melted in all three.

Candle wax didn't melt at all.

And chocolate didn't melt in the cold water and the warm water, but it did melt in the hot water.

Well done.

Okay, so now we are on to the second part of our learning today, which is, scientists make conclusions.

So the results of an investigation can often be recorded in a table, chart or a graph, just like these here.

Andeep and Laura decide to use a table for their data.

So here are their results, which we shared just a moment ago.

Now, results can be used to draw simple conclusions, and suggest improvements.

To do this, scientists need to make sense of their findings and answer their inquiry question.

They also try to explain why the results show what they do by linking them to existing scientific ideas.

So Laura says, "The chocolate melted at 45 degrees.

I think this means that the melting temperature of chocolate is 45 degrees Celsius." Do you agree with Laura? I'll give you five seconds to think about your answer.

Off you go.

Fantastic.

Well done.

So the chocolate did not melt at 25 degrees, this means that the melting temperature of chocolate must be higher than 25 degrees.

However, don't forget that Laura and Andeep did not have any water inbetween 25 and 45 degrees Celsius.

And so therefore Laura would have no idea whether or not chocolate could melt below 45 degrees Celsius and above 25 degrees Celsius.

So, it could have melted at less than 45 degrees Celsius.

But what we know for certain is that the melting temperature of the chocolate is higher than 25 degrees Celsius.

So remember, Laura did not try any temperatures between 25 degrees Celsius and 45 degrees Celsius.

So it's possible that chocolate melts at a temperature which is higher than 25 degrees Celsius, but lower than 45 degrees Celsius.

Laura has changed her conclusion.

She says, "The chocolate melts at a temperature between 25 degrees Celsius and 45 degrees Celsius." Laura says, "I found that chocolate melts at a temperature between 25 degrees Celsius and 45 degrees Celsius, but what is the actual temperature at which chocolate melts?" Now, scientists evaluate their investigations to suggest improvements, and Laura wants to improve the accuracy of her investigation to find the actual temperature at which chocolate melts.

So, can you suggest any improvements to the investigation to help Laura to find a more accurate temperature? I'll give you five seconds to think about your answer.

Off you go.

Fantastic.

Well done.

So Andeep says, "If we had also tried water baths at 30 degrees Celsius, 35 degrees Celsius, and 40 degrees Celsius, we could have got a more accurate value for the melting temperature of chocolate." So you may have also had a very similar idea to Andeep.

So using more temperatures between 25 degrees Celsius and 45 degrees Celsius would have helped them to narrow the results, and find a more accurate value.

To find the absolute exact temperature in degree Celsius would be really, really hard, because they would have to do 20 different water baths, all one degree higher than 25 degrees Celsius, all the way up to 45 degrees Celsius, and that would take quite some time to do.

So which of the following are ways in which you could record the results of an investigation? So could you use a chart, a graph, a prediction, or a table? What do you think? I'll give you five seconds to think about your answer.

Off you go.

Fantastic.

Well done.

The answers are a chart, a graph, and a table.

Remember, your prediction is what you think is going to happen before you carry out an experiment.

Now, which part of an investigation are used to make simple conclusions, and suggest improvements? Is it results, diagrams, a prediction or a method.

So which part of an investigation are used to make simple conclusions and suggest improvements? So again, I'll give you five seconds to think about your answer.

Off you go.

Fantastic.

Well done.

And the answer would be the results.

So, here is task B now then.

It says, use your results from task A to write your conclusion to the inquiry question, and then I want you to suggest improvements to the method.

So think about what we've just learned from Laura and Andeep.

Laura wrote a conclusion, and then she thought really hard about what she had written and whether or not what she had written was accurate.

So you may need to go back over your conclusion a couple of times just to check the accuracy of your answer to your inquiry question.

What have you found out since doing the experiment? Then I want you to suggest improvements to the method.

What could you do better if you were to do it again next time? So what improvements would you make to yours? I'll give you some time now, I want you to pause the video, and have a really good think about this.

Off you go.

Fantastic.

Well done.

So our results showed that the melting temperature of ice is below five degrees Celsius.

The melting temperature of butter is between five degrees Celsius and 25 degrees Celsius.

The melting temperature of chocolate is between 25 degrees Celsius and 45 degrees Celsius.

The melting temperatures of cheese, candle wax and kitchen foil must be higher than 45 degrees Celsius, because they did not melt.

Now, if we did the investigation again, we would try different water temperatures, so we would have a more accurate idea of the melting temperature of each material.

And that is really important to think about improvements that you are going to make to an investigation that you've done, and that's what scientists do all the time.

They're always thinking of ways that they could improve their experiments to ensure that the results are more accurate.

So now we are onto the summary of your learning.

The melting temperature is the temperature at which a solid changes to a liquid.

Thermometers can be used to measure temperature.

Scientists take accurate measurements of temperature in units of degrees Celsius.

The results of an investigation can often be recorded in a table, a chart or a graph.

And results can be used to make simple conclusions and suggest improvements, which is really, really important.

I am so proud of your fantastic work today.

You have worked brilliantly, you've worked safely, and you've conducted a comparative test really well, and I hope that you have learned lots from it.

And you may decide now that you want to have another go at the experiment using your suggested improvements.

Well done.