Video: Inhaled and exhaled air

﻿Hello, and welcome to lesson 13 with me, Miss Wickham. In this lesson, we're going to look at inhaled and exhaled air. For this lesson you're going to need a pencil, a ruler, a pen, and something to write on. Let's make sure that all distractions are away and that you're ready to go. This lesson, we're firstly going to have a look at the composition of the air that we breathe in and out. We're then going to have a look at an experiment that can test this and the finally we'll have a look at how we can display and process the data that we've collected. Here are some recap questions for you to have a go at. Pause the video now, answer the questions, and then resume when you're done. Okay, so let's go through and mark those answers. Number one, what are the reactants of respiration? We should've got oxygen and glucose. What are the products of respiration? Carbon dioxide and water. What is respiration? It is a chemical reaction using oxygen and glucose to release energy. Four, in which organ does gas exchange take place? It is the lungs. Five, what is the name of the air sacs in which gas exchange takes place? We should have got the alveoli. Fantastic. If you've got all of those well done. Okay. So let's start off having a look at this image. This image shows the alveoli. Can you name where we'd find the structure? Good. So this is an air sac that we find in the lungs. Well done. Can you state why this might not be an accurate diagram of an alveolus? Perfect. Good. So the surface area, isn't quite correct. This is showing the air sacs has been quite round, but they're actually more of a folded membrane shape modem. So this image is showing that oxygen is diffusing out of the air sac and into the blood. And carbon dioxide is diffusing from the blood and into the alveoli, which leads us nicely into today's lesson. We're going to look at composition; composition, just meaning how much. What's the differences in the composition of the air that we breathe in and we breathe out. You might already have a good guess about the differences in the oxygen and carbon dioxide levels. This table shows us the composition of the air that we breathe in and breathe out. So let's have a look. The first column labelled gas shows that we breathe in oxygen, carbon dioxide and nitrogen. The second column shows this inhaled gases percentage wise. So you can see that we breathe in 21% oxygen, 0.04% carbon dioxide and 78% of nitrogen. We then breathe out or exhale 17% oxygen, 4% carbon dioxide, and then 78% nitrogen. What I'd like you to do is pause the video. Can you compare the differences in the inhaled and exhaled air? So what is the same and what is different in these? So I'll give you an example. So the nitrogen is 78% when we breathe in or inhale, and it is 78% when we exhale or breathe out. Pause the video now, and then resume when you're ready. Okay. So let's go through and mark our answers. We should have made the following points. The percentage of nitrogen stays the same when we look at inhaled air and exhaled air. The oxygen levels change. The oxygen level when we inhale is larger than when we exhale. The carbon dioxide; there is less carbon dioxide when we inhale, more carbon dioxide when we exhale. Hopefully, you should know that this is because when we take in oxygen, when we breathe in, some of the oxygen will diffuse into the bloodstream. That will then get carried around the body. For exhaled, obviously, that will show because there's less oxygen because it's diffused around into the blood and now on the body. Carbon dioxide, you'll see that the levels increase when we exhale. That's because carbon dioxide is diffusing out of the blood and into the lungs for us to breathe out. That's because this is a waste product of respiration. A few questions; true or false: We breathe out more oxygen than we breathe in? Hopefully we should get that is false. We breathe in oxygen and carbon dioxide. What is the name of the other gas that we also breathe in? Say your answer out loud. We should get... Well done, Nitrogen. What's our alveoli? Say out loud, we should get, They are the air sacs in the lungs, where gas exchange takes place. Fantastic. Okay. So how can we test this theory? So you've just said that the composition of the air that we breathe in contains more oxygen and less carbon dioxide. And when we exhale, it contains less oxygen and more carbon dioxide. I just want you to just pause and just have a think for a second. I've given you a big clue by giving you a candle. See if you can come up with a way that we can test this. Okay. So hopefully we would have got the idea of burning. Now in order for something to burn, it needs to have oxygen. So if we were to burn a candle, for example, in a limited amount of air and we controlled how much oxygen was in that air, that would also allow us to then time, how long it takes for that candle to burn out. When the candle stops burning. That means there's no oxygen left. So, we could have two different scenarios. We could look at inhaled air and exhaled air. We could change the composition, like we've just said with the percentages in that table. We could place candles in those conditions and time how long it takes for them to go out. We just need to collect them. Okay. So, let's have a look at an experiment that could test this. Well, firstly, an important point tonight. This is not an experiment that you need to do at home. This is just an idea of an experiment we could do to test this idea of the composition of air. If however, you are going to do this at home, an important point, that obviously this is a fire hazard. Please make sure you're not doing this in a room where there are strong wind and that you are supervised at all times by an adult. So what could we do? Let's start, off by looking at the image. So you will see there's a candle inside of a bell jar. The bell jar is just an upside down piece of glass. We've obviously no bottom. So the candle will burn, like we've just said, until all the oxygen is used up. When the oxygen is used up, it will no longer burn. The bell jar will capture inhaled or exhale gas. So how would we do this? Firstly, we need to collect our inhaled or exhaled gas. Sounds tricky. Inhaled; we're just going to capture some of the gases in that room. Because that's what we're going to breathe in. For exhaled, we're going to get a participant to breathe out into possibly something like a balloon or a test tube, so we can collect a small amount that. Secondly we're then going to capture that into the bell jar. And then we want to quickly light that candle, so we don't use any of the chapter. We're then going to start our stop watch and we're going to time how long it takes for the candle to stop burning. When the candle starts burning, where they going to stop the stopwatch and then record that data into our table. We will then repeat that for the inhaled or exhaled gas, whichever one we haven't done. Here's the method that I've written for you. A few important points. Don't forget, a method should always contain numbered steps. Secondly, should also include imperative verbs to start each sentence. Don't forget, imperative verbs just means that doing word. So for example, collect, light, start, stop, right. Few questions. What is the name of the piece of equipment which measures time in the experiment? Say your answer out loud. Perfect. We should get stopwatch. What is the name of the verb that should start each step in your method writing? Say your answer out loud. Good. We should get imperative. True or false? The independent variable is a variable we measure. We should get for this one: It is false; it is the one that we change. What are control variables? We should get control variables are the ones that we want to keep the same. Okay. So let's have a look at the variables for this experiment. Don't forget, the independent is the one that we change. Dependence; what we're measuring in the experiment. And control variables are the things that we want to keep the same to make sure that the only factor that is affecting our dependent variable is our independent variable. Pause now, just take your time. See if you can come up with them on your own. Okay, so let's go through. So the independent, the thing we changed was whether it was inhaled or exhaled air. What we measured from that was the time it took for the candle to stop burning. So possible control variables we would need to consider in this one. What was the type of candle or the size of the candle, the size or the length of the wick, the gas jar that we used, and the volume of gas that we collected? Okay. So what do we need for any experiment we do? We need to have a table drawn, ready record our data. Alright, pause the video now. Can you write three features that make a good table? Resume when you're ready. Okay so hopefully you got some written down. So we should have: It should always be drawn with a pencil and a ruler. We need to make sure that we have got straight lines. Second important point is that we need to make sure that the independent variable always goes in the left hand column. That is really, really important. So, independent, always in the left hand column. Now that means that the dependent variable needs to go in the right hand column. We also need to make sure that we have got descriptive headings and these also include the units that we've used in the experiment. And then finally, we need to make sure that we have got room to do repeats and then to calculate averages. That will go underneath the dependent variable. A few questions, What should be included with the the headings in a table of results? Say your answer out loud. Fantastic. You should get it's units. Well done. True or false: The independent variable should be written in the right column. Hopefully we've just said false. The independent goes in the left hand column. What else should be included in the right column of the table? So we should get, below the dependent variable, we should have room for repeats and then a column to also calculate an average. What is wrong with the following table? So hopefully you said there were no units and there's no room for a repeats or averages. What I'd now like you to do, is to draw a table for our results to test the following hypothesis. The time the candle burns for is different for inhaled and exhaled air. Don't forget the table should include the features from the previous slide. Pause the video now and then resume when you're ready. So we should have got a table like this. So the left hand column, should be the independent variable. So it should be the air type, whether it was inhaled or exhaled. The dependent variable should be on the right hand column, so, that should be the time it takes for the candle to stop burning. Don't forget here that we should have our unit. So the unit there would be seconds. So that's the S in the brackets. And you should have, hopefully it also included the opportunity for you to repeat your experiment more than once. And then to calculate an average or mean. Okay, so we've now done the experiment. We would have drawn a table and collected our results. And now we need to analyse that. So we'd have a table filled in like this. Let's have a look at that. So for inhaled, they said that the first time they did this, they got 5.81 seconds. The second time it took the candle 6.01 seconds to stop burning. Third, 2.32 seconds. And forth, 5.94 seconds. Okay, first thing we want to do is obviously calculate a mean. But is there any results that look a bit odd? Good. Hopefully you will notice that the take three or the repeat three, 2.32 seconds is quite outreach for the other three bits of data. We would then call that anomaly. So when we calculate our mean, we are not going to include 2.32, because obviously something's gone wrong there. Some other factors affected that data. Let's look at exhaled. So the first time they did this, they got 3.21 seconds. The second they got 4.22 seconds. The third time, 3.67 seconds. And then lastly, 6.29 seconds. Are there any anomalies in this data? Good. Hopefully we'll notice that the repeat for 6.29 seconds also does not follow the trend of that data. That is quite far out. So we call that an anomaly and we will not include that when calculating our mean. Okay, so how do we calculate mean? Can you say out loud, what's the, what do we need to do? Good. We should be the same thing we do in maps. We are going to add up our results and going to divide by how many there are; not including the anomalies. Don't forget. So first one, we should have then done 5.81, plus 6.01, plus 5.94. Because there's three pieces of data there, we're then going to divide by three. That should get us 5.92 seconds. Then the second time, we should have done 3.21, plus 4.22, plus 3.67. And again, we're going to divide by three because there's three bits of data. That should have got a 3.7 seconds. A few questions. Calculate the mean for the following: three, four, five, three. Perfect. So we should have got, three plus four plus five plus three would make 15, but then divide that by four. And that would get us 3.75 in a calculator. And if we were to round that, that would get us four. Well done if you've got that. What is an anomaly? We should have just said, it's a piece of data that doesn't follow the trend or the pattern of other pieces of data that we've collected. Calculate the mean for the following 6.5, 5, 7, and 13. Okay, so what we should have done was 6.5 plus 5 plus 7, would have got us 18. And then we divide that by three because that's how many bits of data we've just added up. And then we divide that and that would have got a 6. We've not included 13, cause that's obviously the anomaly; it's too far up the dataset. Okay. So at this point we would have done our experiment, identified our variables, completed the method we would have drawn or table collected our results. We've just analysed our results. Now I need to come up with the conclusion. The conclusion does the following things: It describes a relationship that we can see between the two variables. We can use data then to back that up. And we need to then try and use our science knowledge to explain that in a bit more detail. Why has that happened? So, what I to do is to pause the video and have a go at doing that yourself. So, make sure that you're looking at the data, you should have the means written down already. So voice the relationship between the air type and the time the candle took to burn. So have a look for inhaled and exhaled compare the two bits of data that we have got. Pause the video now and then resume when you're done. Okay. So hopefully we would have done that. I'm now going to show you an example or model what this would look like. So an important point to note, Here, I've underlined the key points and put them in bold also. The candle burns for a longer time in inhaled than exhaled. I've done a direct comparison between the two. I've then plucked data from our table and said that the mean burn time for inhaled was 5.92. The mean time for exhaled was 3.7. I've backed up my answer using data from our table. Then finally, I'm going to give some science knowledge, which I should know, to back that argument up to why. This is because inhaled air had a high concentration of oxygen then exhaled air. So the candle would burn longer than if obviously there was less. So I know that oxygen is the main, one of the main components that will allow something to burn. If there's no oxygen, it can no longer burn. It's now time for you to complete a task. A student said, I believe we breathe in more oxygen when running, because our hearts are beating faster than when we are standing still. Design an experiment to test this hypothesis. You will need to include: independent, dependent, and control variables. First thing you need to do. Secondly, then go on to write a method that you could do, including your numbered steps and imperative verbs. And then you also need to then draw a table to record your results. I've done an example of your first bullet point for your method. Pause the video now and then resume when you're ready. Okay, so another important point to make note of, if you've done this about burning, again, you need to make sure that, obviously, if you're lighting a fire, make sure there's no strong winds and make sure that everything an adult is supervising at all times. You do not need to do this experiment. But if you wish to try, then please make sure that you following health and safety. So what are the variables for this experiment? It would be the independent. The thing that's changing is the breathing rates. So that would be before and after exercise or when you're, at resting heart rate, when you stood still, and then just after you finished running. Your dependent variables, what they're going to measure from that is the volume of oxygen inhaled. Control variables would be the altitude. So where abouts you are in the world. If you're up a mountain or down in a valley, make sure you keep that the same and also the same person. An example method: Number one, Collect inhaled breath from the student before they do exercise, trap into a jar. Light a candle, place in the jar and time how it takes the candle to stop burning. You would then repeat the steps one and two with inhaled air after they've exercised; immediately after. Four, you're going to record your data into a table. And your table should look something like this. So again, we need to have our independent on the left hand side. So air type should be inhaled resting and inhaled after exercise. Then the right hand side would be the time taken for the candle to stop burning. Don't forget your units. Okay, so we have looked at the composition of the air that we breathe in and breathe out. So we now know that, we breathe in more oxygen and less carbon dioxide and we breathe out less oxygen and more carbon dioxide. We've looked at an example experiment we could do to test this and what the results would be. We've then looked at how we can display and processes data. So drawing our tables and calculating our means The last thing for you to do, is now going to complete the exit quiz. Well done, for a great lesson. Well done. Goodbye.

Worksheet: Inhaled and exhaled air

Exit Quiz: Inhaled and exhaled air

Completed: Inhaled and exhaled air

This lesson looks at an investigation of the differences in inhaled and exhaled gas, table drawing and writing conclusions.

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Inhaled and exhaled air

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