Lesson video

Hello, my name is Mrs. Merin and I'm so excited to be learning all about microorganisms living on food with you.

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 Mold Growth.

Now, mold is a microorganism and is part of the fungi group, and here we can see mold 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 mold and Jacob says, "I don't think mold 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 mold 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 other types of fungus, mold is a part of the microorganisms group of living things.

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

Which of these statements about mold is not correct?

Is it A, mold is a type of fungus?

B, mold is a living thing.

C, mold is a type of plant, or D, mold is type of microorganism.

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, mold is a type of plant.

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

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 mold grows as food decomposes.

Now scientists can represent data gathered during inquiries in visual ways to help them to analyze 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 inquiries.

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 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 mold was on each type of food after two weeks.

So this is how she set up her experiment.

So bread, it had approximately 22 centimeter squared of mold 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 centimeters squared of mold and the apple, which was approximately six centimeters of mold.

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

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

So she just calculated the squares that had mold 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 mold 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 mold after two weeks and which food had the least amount of mold 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 mold 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 mold on a slice of bread every two days for two weeks.

So here we have got the day, he's gone up every two days and the approximate area of mold in centimeter squared.

Now what kind of graph could he use to show the change over time in the amount of mold 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 mold 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 mold was visible and how much mold 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 mold 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 mold was likely to be on the bread after 11 days, so it would've been around 11 centimeters squared.

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

Now it says to use findings from your own inquiry to represent data about mold 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 mold to make a conclusion.

And Alex says, "I can conclude that mold grew slowly at first, then much more quickly over time.

And I think this is because the more mold 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 mold grows more quickly on bread, B, mold grows more easily on cheese or C, mold 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, mold grows are 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 mold inquiry and remember to explain what happened and why you think it happened using what you know about mold.

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 mold 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 mold needs moisture to grow well.

I was surprised the mango didn't grow the most mold 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's 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 mold.

So mold is a living thing.

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

Mold needs moisture, warmth and nutrients to grow well.

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

Now mold grows quicker in warm conditions so we can store foods in the fridge to keep them cool and slow down that growth of mold, and storing food in the freezer at temperature below minus 18 will prevent mold growth for a long time, as this is much too cold for the fungi to survive.

And mold needs moisture to grow.

So removing as much moisture as possible from foods can slow down the growth of mold.

And this process is called dehydration.

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

Now, mold 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 mold 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 it basically preservatives make it harder for mold 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 mold?

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

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 moldy 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 moldy 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 mold and some foods were stored in a way that stopped mold 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 fat.

And that would just stop those mold 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 mold 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 mold 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 mold from growing quickly.

Now here is your last task for today.

It says, think about the results of our mold inquiry.

What could you have done with your food to slow down the growth of mold?

I want you to 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 mold to grow quickly.

We could have dehydrated our apple so the mold would not have moisture, or we could have stored our food in an airtight container.

" So we are on now to the summary of your learning.

Mold is a living thing, it's a type of fungus, which is part of the microorganisms group, and we can observe the growth of mold if we follow strict safety rules and present our data in graphs to help us make conclusions.

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

You have worked really hard today.

I am so proud of your critical thinking and your fantastic answers, so well done.