Hello, my name is Mrs. Mehrin, and I'm so excited to be learning all about micro-organisms living on food: review.

Welcome to today's lesson from the unit: Why we group and classify living things.

Your lesson outcome today is: I can observe and describe what happens when food is left to decompose over time.

I am so excited to be learning with you today, and I know that learning can sometimes be a little bit challenging, but that's okay because we are going to work really hard together and we're going to learn lots of fabulous new things.

Let's begin.

So here are your keywords for today.

Now don't worry about writing any of these keywords down because I am going to be going over them throughout the lesson.

However, if it does help you, you can jot them down now by pausing the video and doing that.

Fabulous.

Well done.

And here are all of the definitions for today's lesson.

Again, I'm not expecting for you to write these down because I am going to refer to them throughout today's lesson.

However, if it does help you, you can write them down now.

Fabulous.

Well done.

Now our lesson today is split into three sections.

Let's begin with the first section: Presenting data about mould growth.

Now, mould is a micro-organism, and is part of the fungi group, and here we can see mould under a microscope.

Other fungi in this group include yeast, mushrooms, and truffles.

And we can see pictures of these down here.

Now some children are talking about mould and Jacob says, "I don't think mould is a living thing "because it can't walk, run, or swim around.

"It just stays where it is, a bit like this picture." But Lucas says, "I think it is a plant because it's green, "so it must be a living thing." Now what do you think? Who do you think is right, Jacob or Lucas? I'll give you five seconds to think about your answer.

Off you go.

Fabulous.

Well done.

Now mould is a living thing because it can grow, reproduce, and move just like all living things can.

However, it's not a plant because it doesn't make its own food using photosynthesis.

Like all of the types of fungus, mould is a part of the micro-organisms group of living things.

Now let's do a quick check-in of your learning.

Which of these statements about mould is not correct? Is it: a, Mould is a type of fungus.

b, Mould is a living thing.

c, Mould is a type of plant.

or d, Mould is type of micro-organism.

So you are looking for which statement is not correct.

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

If you need a little bit longer, just pause the video here.

Come back once you're ready.

Off you go.

Fabulous.

Well done.

The answer is c.

Mould is a type of plant.

Now Aisha and Alex have been observing mould growth over time on some food, and they've been careful to follow strict safety rules that no one is harmed by the mould.

Now, they've recorded their observations over time, and now they want to present these in a way that will help them make a conclusion about the way mould grows as food decomposes.

Now scientists can represent data gathered during inquiries in visual ways to help them to analyse it and help them to make some conclusions.

So they can do that by creating graphs such as a bar graph like the one on the left-hand side here, or line graphs, the one on the right-hand side, using results from their enquiries.

Now bar graphs are useful for comparing quantities, so the number of things.

So, for example, here we've got a bar graph comparing the height of famous towers, and they are used when the data is not continuous or linked to each other.

Now Alex says, "Can you see the height of each object "in this bar graph?" I'd like you to pause the video here and have a go at that question.

Off you go.

Fabulous.

Well done.

And Aisha says, "Well, I can tell really quickly "which is the shortest and which is the tallest tower." So a bar graph is fantastic for that.

Now, line graphs are useful for showing how things change over time.

So they're used when the data is continuous or it's gathered over time.

And this line graph here shows the temperature of a cup of coffee and how it falls over time.

And Aisha says, "I can see the line goes down, "so I know straight away the temperature fell over time." So it's really clear just like that bar chart.

Now Aisha gathered data on how much mould was on each type of food after two weeks.

So this is how she set up her experiment.

So, bread, it had approximately 22 centimetres squared of mould because she drew a grid on the bag.

So when she put her piece of bread in, she could just calculate the number of squares, which is a really clever way of doing it.

There's also the cheese, which is approximately eight centimetres squared of mould, and the apple, which was approximately six centimetres of mould.

So Aisha's just looking for the mould on the apple.

I know bits of it are brown, but that's not all mould.

So she just calculated the squares that had mould in it.

Now I want you to think really carefully.

Which type of graph would be best to represent this data visually? Would it be a bar graph, or do you think it'd be a line graph? I'll give you five seconds to think about your answer.

If you need to pause the video, and you need to go back and have a look at the charts, that's absolutely fine.

Just come back once you are ready.

Off you go.

Fabulous.

Well done.

So Aisha says, "I've used a bar graph to show my results "because I want to compare the amount of mould "on each food." Now I want you to use Aisha's bar graph to answer the questions.

So, number one, which food had the most mould after two weeks? And which food had the least amount of mould after the two weeks? So, I'll give you five seconds to think about your answer.

If you need longer, you can pause the video here.

Off you go.

Fabulous.

Well done.

So the bread had the most mould, and the apple had the least.

And you can tell just by looking at the bar chart here really quickly, which one's got the most and which one has got the least.

Now Alex gathered data on the area of mould on a slice of bread every two days for two weeks.

So here we have got the day.

So he's gone up every two days, and the approximate area of mould in centimetres squared.

Now what kind of graph could he use to show the change over time and the amount of mould on the bread? Is he going to be using a bar chart, or do you think he might use a line graph for this one? I'll give you five seconds to think about your answer, but if you need longer, you can pause the video here.

Off you go.

Fabulous.

Well done.

So Alex says, "I've used a line graph to show my results "because I want to show how the amount of mould "changed over time." And that is a fantastic way to show that.

Now I want you to use Alex's line graph to answer the questions.

How long was it before the first bit of mould was visible? And how much mould was likely to be on the bread after 11 days? So I'll give you five seconds to think about your answers, but, if you need longer, you can pause the video here and have a go at this activity.

Off you go.

Fabulous.

Well done.

So it was eight days before the first bit of mould was seen because you can see at eight days the line is starting very slowly to go up at the eighth day.

Now it says how much mould was likely to be on the bread after 11 days? So it would've been around 11 centimetres squared.

So we just have to look halfway in between the 10 and the 12th day and then go up in our chart, and it would be around 11 centimetres there, 11 centimetres squared.

Now it says to use findings from your own inquiry to represent data about mould growth.

So you may have done this if you did the previous lesson with me.

Now if you don't have your own data, that's okay.

You can choose either Laura or Jun's results from their inquiry, and I want you to choose the best type of graph to represent your data visually.

So here we have got Laura's results, and here we have Jun's results.

So if you need either Laura or Jun's, that's absolutely fine.

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

And you can go and rewind on this video to have a look at Laura's results and have a look at Jun's results.

Okay.

Off you go.

Fabulous.

Well done.

So the best type of graph to represent the data visually would've been a bar chart for Laura's one.

And Laura says, "I created a bar chart to show my results.

"How did you represent your data?" So how did you choose to do Laura's data? Have a look at yours.

Have you chosen the correct type of chart? If you haven't, that's okay.

You can pause the video here, and you can go and have another go.

Fabulous.

Well done.

And the best type of graph to show Jun's results would have been a line graph.

So if you haven't done a line graph for this one, and you'd like to change it, you can pause the video here, and you can have a go at doing that.

Fabulous.

Well done.

Now we are on to the second part of our learning today which is making conclusions.

Now that our results are represented in the correct type of graph, it's easier to make conclusions about our inquiries.

Now Alex uses his line graph and shows what he has learned about mould to make a conclusion.

Alex says, "I can conclude that mould grew slowly at first "then much more quickly over time." "And I think this is because the more mould there was, "the more spores it produced, "which allowed it to grow more quickly." Now I'd like you to think about this question here.

It says, "What can Aisha conclude about her results?" Is it: a, that mould grows more quickly on bread.

b, mould grows more easily on cheese.

Or c, mould grows more easily on apples.

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

Off you go.

Fantastic.

Well done.

The answer is a, mould grows more easily on bread.

Now this is your second task for today.

I want you to use your own graph to make a conclusion about your mould enquiry.

And remember to explain what happened, and why you think it happened using what you know about mould.

So I'll give you some time now.

I'd like you to pause the video here and have a go at that activity.

Fabulous.

Well done.

So here, Laura has said, "Using my results, "I can conclude that it is easiest "for mould to grow on bread and hardest on crackers.

"I think it didn't grow very well on the cracker "because crackers are very dry, "and mould needs moisture to grow well.

"I was surprised the mango didn't grow the most mould "because it is very moist.

"I would like to carry out further inquiries "to find out why this happened." Now, is your conclusion similar to this? I'd like you to have a look at what you've written, and have a look at what Laura has written, and see whether or not you've added enough detail to your conclusion.

If not, you can pause the video here, and you can have a go at that.

Fabulous.

Well done.

Now we are on to the final bit of our learning today which is preventing and slowing down mould.

So mould is a living thing.

Just like other living things, it needs certain conditions to survive and grow.

Mould needs moisture, warmth, and nutrients to grow well.

And we can use what we know about what mould needs to slow down or prevent its growth.

Now mould grows quicker in warm conditions, so we can store foods in the fridge to keep them cool and slow down that growth of mould.

And storing food in the freezer at a temperature below -18 will prevent mould growth for a long time as this is much too cold for the fungi to survive.

And mould needs moisture to grow.

So removing as much moisture as possible from foods can slow down the growth of mould, and this process is called dehydration.

So dehydrated or dried fruits, like raisins, for example, will last much longer before going mouldy than if you have fresh moist fruits such as grapes.

Now, mould spores travel through the air and are able to grow when they land somewhere with moisture and a food source.

So another way that we can slow it down is to keep food in airtight containers which reduces the amount of mould spores it can actually come in contact with.

And another thing that we can do that a lot of companies do is to add something called preservatives.

And these substances can be added to food, and it helps it to last much longer.

And basically preservatives make it harder for mould to actually grow.

And some preservatives are artificial, so that means that humans have made them, and some preservatives are natural such as using sugar, lemon juice, vinegar, or salt.

Now, which of these actions would slow down the growth of mould? Remember, there could be more than one correct answer here.

Is it by: a, adding preservatives, b, adding moisture, c, keeping in a sealed, airtight bag, keeping it in a fridge, or keeping it in a warm place.

So think about what mould needs in order to grow, and then think about what you could do in order to slow down that growth of mould.

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

Off you go.

Fabulous.

Well done.

So it would be a, c, and d.

Now, how did people stop their fresh food from going mouldy before fridges or artificial preservatives were invented? So what do you think? How do you think people might have stopped their fresh food from going mouldy before? I'll give you five seconds to think about your answer.

Off you go.

Fabulous.

Well done.

So lots of different methods would've been used in the past to slow down the growth of mould.

Now, fish and meat could be packed in salt, and that would draw out the moisture.

So here we have a picture of dried beef.

And this meant that the food would last longer.

So if it was packed in salt, and all the moisture was able to come out of that food source, then that food would last a lot longer because mould needs that moisture to grow.

And some foods were stored in a way that stopped mould spores getting to them through the air.

So, for example, this could be done by coating foods in wax or putting them in pots and covering the top with a thick layer of butter or animal flat.

And that would just stop those mould spores getting to them.

And now some foods are stored in natural preservatives like vinegar or brine, which is salty water.

And we still do use this technique to preserve foods now, and you might have tried tuna stored in brine or pickled onions kept in vinegar.

Now let's do a quick true or false to check your understanding so far.

People were still able to stop mould from quickly growing on fresh foods before fridges were invented.

Is that true or is that false? I'll give you five seconds to think about your answer.

Off you go.

Fabulous.

Well done.

The answer is true.

Now, is it because: a, people used other methods such as pickling and dehydration to prevent mould from growing quickly? Or is it because people added lots of artificial preservatives to their food and stored it in airtight plastic containers? Again, I'll give you five seconds to think about your answer.

Off you go.

Fabulous.

Well done.

The answer is a.

People used other methods such as pickling and dehydration to prevent mould from growing quickly.

Now here is your last task for today.

It says, "Think about the results of our mould inquiry.

"What could you have done with your food "to slow down the growth of mould?" I want you think about as many ideas as you can.

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

Off you go.

Fabulous.

Well done.

So Aisha says, "We could have kept our food in a cold place, "so it wasn't warm enough for mould to grow quickly.

"We could have dehydrated our apple "so the mould wouldn't have moisture, "or we could have stored our food in an airtight container." So we are on now to the summary of your learning.

Mould is a living thing.

It's a type of fungus which is part of the micro-organisms group, and we can observe the growth of mould if we follow strict safety rules and present our data and graphs to help us make conclusions.

Mould growth can be slowed down or prevented in different ways, including dehydration, refrigeration, and adding preservatives.

You have worked really hard today.

I'm so proud of your critical thinking and your fantastic answers.

So, well done.