JP1 COMBINATION REACTIONS
This eighth-grade science lesson is about combination reactions. Specifically, it focuses on the reaction between hydrogen and oxygen to produce water. It is the 10th lesson in a sequence of 30 lessons on chemical changes. The lesson is 52 minutes in duration. There are 33 students in the class.
| Time | Caption |
|---|---|
| 00:00:00 | [bell] |
| 00:00:08 | Okay then, let's begin. |
| 00:00:12 | Okay. |
| 00:00:17 | Stand up. |
| 00:00:21 | (Second year, class three), currently 35 students. Those who are absent are Yasui Ami-san, Mori Mari-san, Go Hisashi-kun, and uh, Marui Hikaru-kun is also absent. |
| 00:00:34 | In a consultation room, Kanno Ayumi-san, and Hoshi Toru-kun are present. Bow. |
| 00:00:40 | //Okay then, let's begin. |
| 00:00:46 | I kind of feel a little nervous. |
| 00:00:50 | Okay then, I would like to confirm what we've done so far. Uh, in our last class we used some baking powder. What is the main substance in here called? |
| 00:01:01 | Sodium //bicarbonate. |
| 00:01:03 | Hm? |
| 00:01:04 | Sodium bicarbonate. |
| 00:01:04 | //Sodium bicarbonate. |
| 00:01:05 | Sodium bicarbonate is the main substance in here right? |
| 00:01:21 | And when you make cake, you... heat this up. And then it rose. And what came out to make it rise? |
| 00:01:34 | Gas. |
| 00:01:35 | Gas. |
| 00:01:39 | Because gas came out. |
| 00:01:41 | Okay then, so what we're preparing for today is to find out what kind of change occurred by the gas coming out. But let's do a little confirmation. |
| 00:01:50 | When I asked what kind of gas this was, I received a few candidates. What were they? |
| 00:01:56 | Carbon dioxide. |
| 00:01:57 | Carbon dioxide. |
| 00:02:00 | It could be. |
| 00:02:07 | It could be. What other possibilities are there? |
| 00:02:12 | Sodium bicarbonate. |
| 00:02:18 | Sodium bicarbonate. |
| 00:02:29 | Sodium bicarbonate. |
| 00:02:31 | So there is the chance that this sodium bicarbonate directly turned into the gas form of sodium bicarbonate. We don't know. |
| 00:02:39 | It could be this one. It could be this one. And what we know is the way to confirm only this one. So uh, well we're going to confirm it today, but if it were this one what happens and how? |
| 00:02:52 | //Limewater. |
| 00:02:53 | //Limewater, right? We talked about using this. |
| 00:02:58 | If the limewater turns cloudy white, then it's probably this. |
| 00:03:03 | If it doesn't turn cloudy white then- |
| 00:03:12 | there is a chance that it's this one. |
| 00:03:22 | It might be something other than carbon dioxide, so if that happens then we'll have to do another experiment. |
| 00:03:28 | You guys thought that it was carbon dioxide, right? So we want to try and confirm it with this. |
| 00:03:36 | Let's be sure to confirm at least these points. Gas is supposed to come out. You confirmed that it did come out. If it is carbon dioxide then the limewater is probably going to turn cloudy white. |
| 00:03:45 | If it doesn't turn cloudy white, then as another possibility it could be sodium bicarbonate that changed its state. |
| 00:03:58 | There's the possibility that it changed its state. So I think that you can come to your conclusions in this way. |
| 00:04:05 | And then uh, I've put the experiment confirmation on the handouts so please look at your handouts. |
| 00:04:17 | And I'd like to confirm the procedure, so please take a look at the procedures. I'd like to begin the preparations now. |
| 00:04:30 | Uh, what we're going to need to prepare is, uh, there's a stand here, so will you come and get the stand from here. I'll have you take a stand from here. |
| 00:04:45 | And then, matches. Also, the cans for used matches are in its usual place on the shelf in the back. And the test tube holders are right here, so take one per group. |
| 00:04:54 | And the test tubes. All you need is one test tube. One is enough. Please take one piece of paraffin paper please. Also one spoon. |
| 00:05:05 | And there's also a rubber stopper with a glass tube right here, so take one of these as well. |
| 00:05:09 | Take one of everything. |
| 00:05:11 | And I'll have some limewater ready here, so I'll have you take that. |
| 00:05:15 | And about the sodium bicarbonate, I put it in here, and I have it wrapped in aluminum foil to protect it from getting stale, so take this off and use it please. |
| 00:05:30 | And then, when you first begin, have a test tube ready and... in this way, well, there's a few but after you get it ready, from here... put about... one spoon full. I think this is plenty. |
| 00:05:59 | And after you take it with the spoon... put it inside here please. Some of it spilled a little, on the hand. |
| 00:06:09 | So put in here like this. |
| 00:06:24 | The important part is when you put this in... make the bottom a little higher. And I think the best place to hold it is about half way. Okay, make it a little higher. |
| 00:06:39 | If you put it up too high then this'll fall right down, okay? And you can adjust it here to turn it. And you can also adjust the height with this as well. |
| 00:06:47 | And now I'm going to light [the burner] so I'm going to take this, where I put the limewater in and I will put this inside of the limewater. |
| 00:07:03 | And then, uh light [the burner], oh leave this like this in the beginning. After you light [the burner], put it in the limewater and check out the reaction please. |
| 00:07:13 | And then you should get a reaction. You should get a result. I think that you'll get some kind of result. And then write it down on your paper and make a decision. |
| 00:07:24 | You're also going to turn this off, however make sure that you take this out first. Remove this. |
| 00:07:31 | If you don't remove this and take it out, there's the possibility that you'll get back wash in here. There's the possibility that you'll get backwash so be careful, be very careful concerning this point. |
| 00:07:41 | There are two particular points to warn you about. One is to make sure you have the bottom part raised. And also to make sure you take this out before you turn off [the gas burner]. |
| 00:07:49 | Make sure you are really careful concerning these two points as you do this. |
| 00:07:53 | Let's see, are you okay concerning the procedure? |
| 00:07:56 | Okay then, it's already been prepared for you right here, so I would like each group to prepare and start the experiment, please. |
| 00:08:23 | This? Is it okay if we take this? |
| 00:08:26 | Yes, that's fine. |
| 00:08:27 | The cameraman may have a little cold. |
| 00:08:38 | Take the one right here. |
| 00:08:54 | Okay here, take them. |
| 00:08:58 | If you don't have enough matches then take more from here. |
| 00:10:16 | Did you get matches? |
| 00:10:17 | I got them. |
| 00:10:27 | Teacher, I (spilled). |
| 00:10:28 | That's okay. Uh, there's a wiping cloth right there. With the wiping cloth. //Will you do that? |
| 00:10:31 | //Okay. |
| 00:10:33 | Teacher, teacher. |
| 00:10:35 | This is a little too much. I said one light scoop. |
| 00:10:37 | Teacher, is this about //right? |
| 00:10:38 | //Uh huh, this is about right. |
| 00:10:39 | It's supposed to be one light scoop. This is a little too much, so why don't you take this and make it about half. |
| 00:10:47 | Teacher, is it not good to put too much in? |
| 00:10:48 | No. About one scoop with the spoon. |
| 00:10:50 | Uh huh, one big scoop is fine. |
| 00:10:51 | One big scoop. |
| 00:11:04 | Teacher. |
| 00:11:05 | Yes. |
| 00:11:06 | We won't need this? |
| 00:11:07 | Oh, okay then //save it just like this. Just save it like this. |
| 00:11:08 | //Teacher. |
| 00:11:08 | Teacher. |
| 00:11:12 | Open this up //and. |
| 00:11:14 | //Murai-san, that's the opposite way. Murai-san, the other way. |
| 00:11:16 | Teacher. |
| 00:11:17 | The other way, the other way. You have to wind it like this. Yes. |
| 00:11:19 | Murai-san, the other way. |
| 00:11:20 | Teacher, can we start doing this? |
| 00:11:21 | Oh, that's fine. //You can start. |
| 00:11:22 | //Over here! |
| 00:11:23 | Yes. |
| 00:11:24 | That's about right. |
| 00:11:25 | Is this about right? |
| 00:11:26 | That's about right. |
| 00:11:27 | That's good. That's good. |
| 00:11:31 | I don't know if we have it or not. |
| 00:11:38 | Don't overdo it. That's good enough right there. It might be better to bring that more over here a little. |
| 00:11:42 | This? |
| 00:11:43 | Yeah well, I guess that's good enough. That's good enough right here. Okay. |
| 00:11:46 | If you make it too tight then it might crack right here. |
| 00:11:49 | Okay. |
| 00:11:49 | Make sure you tighten this part correctly. |
| 00:11:52 | Daichi, this is next. |
| 00:11:58 | Uh huh, that's fine. You should do it properly. Make sure that this won't do. All right. |
| 00:12:09 | Teacher, about this much? |
| 00:12:10 | Uh huh, about that much. |
| 00:12:17 | Clamp it. |
| 00:12:18 | Teacher, how do I make it so this thing goes up? |
| 00:12:21 | Oh you have to do this a little bit to this part. |
| 00:12:24 | Teacher, this is kind of sticky. It's kind //of oily. |
| 00:12:27 | //Uh huh. |
| 00:12:31 | Is this good enough? |
| 00:12:32 | Yeah, that's good enough. |
| 00:12:35 | About this much. |
| 00:12:36 | Right, right, right. |
| 00:12:38 | Can I turn it on? |
| 00:12:40 | The first time is //(likely to fail). |
| 00:12:42 | //Hey, but is this okay with this one? |
| 00:12:44 | The position is too high. |
| 00:12:46 | Okay, okay, okay, okay. |
| 00:12:48 | It might be better to adjust this after you light it. |
| 00:12:52 | Okay then, why don't you light it. |
| 00:12:59 | Teacher, is this okay? |
| 00:13:00 | Yes. Yes that's fine. |
| 00:13:08 | It went out again. |
| 00:13:09 | Teacher. |
| 00:13:10 | Why don't you put it in little by little. You have to make it so that you don't get any air in there. |
| 00:13:16 | The other way, the other way. |
| 00:13:17 | (It doesn't matter.) |
| 00:13:20 | Okay, okay, why don't you try it like this. |
| 00:13:21 | Okay. |
| 00:13:47 | We have a wiping cloth, so just use the wiping cloth. |
| 00:13:56 | We have a little more. |
| 00:14:04 | That's so fast. |
| 00:14:06 | Ohh, this, this. |
| 00:14:13 | Carbon dioxide. |
| 00:14:21 | You have to (take some more out) and put it there. That's enough. |
| 00:14:33 | It's good like this, but why don't you lower it a little more? |
| 00:14:40 | Uh huh. Good. And this, now put this inside of that. |
| 00:14:56 | Why, why? |
| 00:14:57 | It's official. It's officially carbon dioxide. |
| 00:14:59 | The water came out from here. |
| 00:15:03 | Nothing, nothing's coming out? |
| 00:15:05 | Huh? It //came out. |
| 00:15:06 | //We just did it right now. |
| 00:15:07 | You did it? Oh, okay, okay. Then you have to take this out. |
| 00:15:11 | Oh, that's right! |
| 00:15:13 | Teacher, is this good enough? |
| 00:15:15 | That's good. Why don't you try and lower this a little more. What is this? What is this for? You don't need this. Okay then, lower this a little. |
| 00:15:30 | Whoa, incredible, it's starting to turn //white. |
| 00:15:31 | //Incredible. |
| 00:15:35 | Okay then, for those groups who got a reaction... turn it off without making a mistake. |
| 00:15:49 | Okay, for those groups who got a reaction. |
| 00:15:52 | Teacher, the reaction was over already? |
| 00:15:54 | Hm? Oh, that's good. |
| 00:15:55 | Hey, you're trying to turn it (with turning the stopcock on //all the way.) |
| 00:15:58 | //It's okay now. Will you take this off? |
| 00:16:00 | What happened? You don't have a match? |
| 00:16:05 | Take the matches that are there. |
| 00:16:16 | For the groups that already have results. For the groups that already have results. Please write your results and analysis in your notebooks. |
| 00:16:37 | (That's strange.) Let's call the teacher. |
| 00:17:01 | Oh, it lit. Okay then, I'll do the rest. |
| 00:17:09 | Teacher (inaudible). |
| 00:17:10 | Hm? |
| 00:17:11 | (inaudible). |
| 00:17:13 | What you think you can derive from the results. |
| 00:17:17 | Oh, you got a result right? |
| 00:17:19 | Teacher, teacher. This part won't turn. |
| 00:17:23 | Oh, really. |
| 00:17:30 | Oh, it turned. |
| 00:17:31 | That's fine. Okay then, you can do it like this. |
| 00:17:33 | Okay. |
| 00:17:42 | Teacher, the thing which built up is- |
| 00:17:44 | Uh huh. |
| 00:17:45 | More than it's getting cloudy, it's //building up at the bottom. |
| 00:17:46 | //Oh, see the white cloudy stuff is building up at the bottom right now. |
| 00:17:49 | The //white cloudy stuff is (building up a the bottom)? |
| 00:17:50 | //What's this white substance? |
| 00:17:52 | I'll tell you what that is on a separate occasion soon. |
| 00:17:58 | It gets cloudy white. |
| 00:17:59 | Since you got this. What kind of change does that mean you got? |
| 00:18:06 | I have to write it down, right? |
| 00:18:12 | Okay then, let's do it together later. |
| 00:18:17 | Teacher, can I write it down below the part where it says results? |
| 00:18:18 | Uh huh, below the part where it says results. It's the... part for the analysis. Okay? |
| 00:18:32 | As you heat up sodium bicarbonate- |
| 00:18:51 | As you heat it up. |
| 00:18:57 | And, given that gas was produced. |
| 00:19:08 | Given that gas was produced, how does the sodium bicarbonate- |
| 00:19:18 | What kind of change... can you say occurred? You can at least say that it's certainly not that one. |
| 00:19:31 | Then I'll ask you. What kind of gas was this? |
| 00:19:38 | What kind of gas was //this? |
| 00:19:39 | //Yes. |
| 00:19:42 | This gas was? |
| 00:19:43 | Yes. |
| 00:19:48 | Okay then you tell me, Amano-kun. |
| 00:19:52 | Carbon dioxide. |
| 00:19:53 | It was carbon //dioxide, right? |
| 00:19:54 | //What? |
| 00:19:56 | This gas that was produced was carbon dioxide. |
| 00:20:04 | A gas called carbon dioxide was produced. |
| 00:20:13 | That's... what we found out. However, the identity of the gas in the baking powder that made the sweets rise was this carbon dioxide. This is what we confirmed with everyone. |
| 00:20:31 | What being carbon dioxide means is... that we know it can't be this, right? |
| 00:20:41 | So, because carbon dioxide was generated, can we say that when heating sodium bicarbonate, did it change or not change its state? |
| 00:20:52 | You can't say //that it did. |
| 00:20:53 | //You can't say that it did, right? In this case there was the chance that it was sodium bicarbonate. However, since we have this. The possibility of this was relinquished. |
| 00:21:05 | So it is not a change of state. As ice turns to water and water turns to steam. |
| 00:21:11 | In the same way, we thought that if we heated sodium bicarbonate it might turn into a gas form of sodium bicarbonate. But that was not the case. |
| 00:21:19 | Something obviously different came out. |
| 00:21:22 | Okay then, if the change in the sodium bicarbonate was not a change in state, then what kind of change occurred? |
| 00:21:35 | The fact that carbon dioxide was generated means that it was not a change of state. This is not a change of state. |
| 00:21:54 | It is not a change of state. Okay. Then what was it? |
| 00:22:01 | So now, with those test tubes once more, with those test tubes. Hey, did you leave them as they were? Did you take them down? As well as the test tube? |
| 00:22:15 | Did you take them down? For those of you who took them down. |
| 00:22:22 | Well, I want you to do something. Uh, for those of you who haven't taken them down, leave it as it is and take a look at the insides, what's left. |
| 00:22:30 | Uh, you can leave it the way it is. Don't take it down. Don't take it down and look at it the way it is. Is there something that you noticed? |
| 00:22:46 | Having looked in the test tube. How is it? |
| 00:22:55 | I can't tell. |
| 00:22:56 | Okay, please tell us about what have you noticed. |
| 00:23:01 | Okay then Soga-kun, say it, will you? |
| 00:23:03 | It's hardened. |
| 00:23:04 | It's hardened. Let's see, it's a white powder, right? This is hardened. Any others? Is there anything else you noticed? Okay Kudo-san. |
| 00:23:24 | There's some vapor. |
| 00:23:25 | There's some vapor. Are there some water droplets? |
| 00:23:31 | There seem to be some water droplets. |
| 00:23:38 | There are some water droplets. If you tell me that there's vapor, you can already see it so it's called a water droplet. Vapor is something that's already here in a form you can't see. |
| 00:23:46 | So there's some water droplets. So you can see these two things. You've confirmed it, right? At the very least. This water droplet. Is it really water? How should we check it? |
| 00:24:04 | Lick it? |
| 00:24:07 | Litmus //paper. |
| 00:24:08 | //Litmus paper. |
| 00:24:13 | Can we use litmus paper? |
| 00:24:18 | We can't lick it. So now, actually, in order to see if it's water or not. We have this convenient thing that won't react if it's not water and will react if it is. |
| 00:24:30 | What's that? |
| 00:24:34 | Hm? Do you know what it is? You don't know? Okay then I'll show it to you. |
| 00:25:00 | Let's see. I want to get one that has a nice color. |
| 00:25:10 | We have this blue colored thing. And it's not litmus paper but a cobalt chloride paper. |
| 00:25:34 | If you put it in water... hold on. |
| 00:25:48 | If you put this in. The color may be a little difficult to see. What color did it become? |
| 00:25:55 | Pink. |
| 00:25:57 | If you let it react to water, this becomes pink. It's just that today, it's been really humid recently, right? Well, Kudo-san said water vapor before, and that's what we have. |
| 00:26:09 | There's a lot of vapor here we can't see. In the air. If you can see it with your eyes, then think of it as a water drop, or fog. |
| 00:26:18 | And, this uh... is in here with the intent to keep it as dry as possible, so take it with tweezers and I would like to have you... expose it. |
| 00:26:40 | And the other thing is how to confirm the substance that's left over, so I'm going to explain regarding that, so I'm going to pass out one more handout, so do it please. |
| 00:26:53 | Two, four- |
| 00:28:12 | Okay, are you ready? I would like to check what the remaining substance is with the method written there. |
| 00:28:20 | When we just heated up the sodium bicarbonate, at the very least we confirmed that carbon dioxide was generated. |
| 00:28:26 | And then we noticed that there's some kind of liquid at the mouth of the test tube. This may or may not be water droplets. Please check to see if it is water with the cobalt chloride paper. |
| 00:28:42 | If this, right after you put it in. Right after you put it in. If it doesn't turn red. If it doesn't turn pink, then that means that it's something different. |
| 00:28:55 | So how you check that is, you have some liquid at the mouth [of the test tube], right? At the mouth, right? The people who moved to the top should be the same, too. Uh, it's at the mouth. |
| 00:29:05 | Remove that. Leave it removed, and then quickly take this from here with tweezers and then put it on the mouth please. Do you understand? |
| 00:29:18 | And then check to see if it changes. If you just sit there and space out then it'll start sucking up the moisture in the air and it'll change color with the moisture in the air, so be careful about that. |
| 00:29:27 | So if that's the case or not. If it's not, then this will not change. |
| 00:29:32 | Okay. So now. One more thing. About the substance that was left over on the bottom. The substance that's left over on the bottom. |
| 00:29:41 | The substance left over on the bottom is... left kind of like this right now. What is this left over substance? |
| 00:29:53 | You're saying something's hardened up, and it's white. What could it be? There's a chance that everyone knows what this is. Can you say that this is sodium bicarbonate? |
| 00:30:15 | Can you say that this is sodium bicarbonate? |
| 00:30:19 | We don't know. |
| 00:30:20 | We don't know. |
| 00:30:21 | We don't know, right? If we get the same reaction with the same kind of process, then we can say that it's this. |
| 00:30:28 | So now, we are going to do it like this. We are going to stand this part up that's left over. We're going to stand it up. |
| 00:30:38 | Over here, we're going to stand it up in this way. Well. |
| 00:30:45 | This hasn't reacted, but stand it up. |
| 00:30:47 | And then, we will take one more scoop of sodium bicarbonate again. With a spoon. You guys have some left, right? A little bit of sodium bicarbonate. |
| 00:31:00 | And then take this as you did before, take one scoop with the spoon and take one more test tube please. So take one more test tube again please. You can just take it from here. |
| 00:31:18 | You should still have your spoon and paraffin paper so you can just go ahead and use the ones you have. And then... you will... put this in. |
| 00:31:28 | You'll line up the one that's left over at the bottom of the test tube and the sodium bicarbonate that hasn't reacted yet. |
| 00:31:35 | And then I have some distilled water ready for you here. So, please put the distilled water in so that it comes out to about equal amounts. There may be some that don't fit too well. |
| 00:31:44 | If there are some that don't quite fit too well, then. Wait a moment okay? |
| 00:32:02 | The amount of water you should put in, should be about one third to one fourth of the test tube. |
| 00:32:16 | If you put too much in then it becomes difficult to shake. |
| 00:32:22 | And then, you're checking to see if they are the same thing, so shake it like this and check to see how it dissolves as well. Shake it and check to see how it dissolves as well. |
| 00:32:33 | To see if there's a difference. And then, after you've done that, you put the phenolphthalein in it. You take it as it is, vertically, and then make it horizontal, and you put in a few drops. |
| 00:32:50 | One or two drops. Like this. It drops. Please put this in. |
| 00:32:57 | And then if they're the same thing then they should react the same. If they are different substances then they should have different reactions. Record your results on your cards please. |
| 00:33:09 | Do you understand what you have to do? |
| 00:33:10 | Yes. |
| 00:33:11 | Okay then, one test tube and a cobalt chloride paper. And in order to take the cobalt chloride paper, you need a set of tweezers, distilled water and some phenolphthalein. |
| 00:33:35 | Kana-chan, do you have that over there? Can you bring that? |
| 00:33:58 | When you take out the cobalt chloride paper... stick it on right after you take out the rubber stopper or it'll suck up the moisture in the air. |
| 00:34:15 | Hm, are you missing something? Hm? |
| 00:34:16 | This //paper. |
| 00:34:17 | //The cobalt chloride paper? This one. |
| 00:34:25 | Are we supposed to just take it like this? |
| 00:34:26 | Uh huh, just take it like that. |
| 00:34:49 | How did it turn out when you stuck it on the water droplets. |
| 00:34:52 | It changes. |
| 00:34:53 | Okay. |
| 00:34:54 | It's pink. |
| 00:34:55 | Okay then, record that. |
| 00:34:56 | Yes. |
| 00:35:08 | Teacher, what do we do with this //one that turned pink? |
| 00:35:09 | //Okay, good. Just leave it there and we'll put it away later. |
| 00:35:15 | It changed. Okay then, record. Record when you get your results. |
| 00:35:20 | You got it, right? |
| 00:35:21 | Yes. |
| 00:35:22 | Okay. Then please record it. |
| 00:35:31 | Where should I leave this? Here? |
| 00:35:33 | Oh, it would be fine if you left it around here. Oh, you could just leave it with the paraffin paper. |
| 00:35:38 | Yeah, that's right. |
| 00:36:17 | Are you still going to put more in? |
| 00:36:29 | You say such complex things. |
| 00:36:41 | I didn't really understand that one. |
| 00:36:51 | Okay then do it one more time. |
| 00:37:00 | Will you shake this? |
| 00:37:19 | Yeah, you can do it so it has about the same amount of water. Let's see, you have to go get one more test tube. Oh, you brought it. Okay then take this and remove this and stand it up. |
| 00:37:28 | Uh huh. |
| 00:37:29 | And then put in the water the same way. |
| 00:37:37 | Ohh? //well this is also one type of way it dissolves, so... |
| 00:37:38 | //It won't dissolve. |
| 00:37:48 | Isn't this kind of pink? |
| 00:37:50 | Ha, ha, it's kind of (inaudible). |
| 00:37:57 | Oh, it's starting to dissolve. |
| 00:37:58 | Oh, it's really pink. |
| 00:38:00 | Okay, that's good enough. |
| 00:38:03 | It won't dissolve. |
| 00:38:04 | Oh, well that's one kind of result as well, right? So it'll be good to record that. |
| 00:38:11 | Okay. |
| 00:38:12 | Teacher. This (changed colors). |
| 00:38:14 | Hm? |
| 00:38:15 | Where should we (inaudible)? |
| 00:38:17 | First of all, did you get a result? Then write your results down. Write your results down and from your results, with these two substances. |
| 00:38:26 | This hydro-, can you or can you not say that this substance formed is in fact sodium bicarbonate. Write that here. |
| 00:38:31 | Wait. (inaudible). |
| 00:38:34 | If it were the same reaction then. This is- |
| 00:38:37 | Oh, that's right, that's right, that's right. |
| 00:38:38 | This is the original sodium bicarbonate //right? |
| 00:38:40 | //Yes, yes, yes. |
| 00:38:41 | This one's the one we heated. |
| 00:38:43 | Okay. |
| 00:38:44 | Let's see. This one is- |
| 00:38:50 | I made a mistake. |
| 00:38:51 | Who cares because we're going to (throw it away) anyway. |
| 00:38:53 | Let's put it in a little sooner. |
| 00:38:59 | Teacher (I spilled it.) |
| 00:39:00 | Oh, that's fine. It's okay. |
| 00:39:06 | You couldn't do well? Okay then take the cap off of this and uh, you can put it in a little, one drop at a time. |
| 00:39:13 | A little at a time. |
| 00:39:14 | Yes. |
| 00:39:15 | You should leave this around here and- |
| 00:39:18 | I don't know. |
| 00:39:19 | You should move a little bit and then. Like //this. |
| 00:39:23 | //As expected! |
| 00:39:24 | As expected! |
| 00:39:25 | Let's do it. |
| 00:39:26 | How many drops would be good? |
| 00:39:29 | How many drops? I think it's about three. |
| 00:39:34 | I think it turned kind of pinkish. |
| 00:39:40 | Teacher. |
| 00:39:41 | Yes. |
| 00:39:41 | (inaudible) |
| 00:39:43 | Huh? |
| 00:39:44 | (inaudible) |
| 00:39:45 | Uh huh. Was the reaction the same? Was it different? It was different, right? Then write that down in your records. |
| 00:39:50 | It's changing. |
| 00:39:51 | It's different. |
| 00:39:57 | Did you put it in both of them? |
| 00:39:58 | Yes, we did. |
| 00:40:08 | Why don't you try putting one more drop in each of them. |
| 00:40:09 | Okay. |
| 00:40:34 | This isn't it. Is this the one that you put on that side? |
| 00:40:37 | Yes. |
| 00:40:38 | Okay then, write down the results of this one. |
| 00:40:40 | It's really different. |
| 00:40:41 | What a color. |
| 00:40:43 | It's quite a lot different, isn't it? |
| 00:40:57 | (inaudible) is important. |
| 00:41:00 | What that mean is- |
| 00:41:01 | In that part, that part? |
| 00:41:03 | It is (inaudible), isn't it. |
| 00:41:05 | Which one is this? |
| 00:41:10 | You mean, this test tube? |
| 00:41:31 | We put too much in it. (inaudible) |
| 00:41:43 | Uh, which one is the one which is really pink? |
| 00:41:45 | Okay, write your results please, okay? |
| 00:42:15 | Okay then. Stop what you're doing for a moment and look up at me please. |
| 00:42:55 | Okay then, let's start the confirmations. |
| 00:43:09 | What kind of reaction did the cobalt chloride paper have when you put it up against the mouth of the test tube? |
| 00:43:16 | Okay, Koga-kun. |
| 00:43:20 | Uh huh. What kind of, what happened? |
| 00:43:22 | It turned //red. |
| 00:43:23 | //It turned red. |
| 00:43:29 | It turned a light red more than it did pink, didn't it? So given that it turned red, what can we say the liquid at the mouth was? Who was able to deduce this? |
| 00:43:42 | Given that this turned red. This is? |
| 00:43:47 | Okay then, Kimura-kun. |
| 00:43:49 | Water. |
| 00:43:50 | It means that it was water, right? What was made here was water. It's been confirmed that it was water. |
| 00:43:56 | Okay then, we tried putting the phenolphthalein in. And we compared it to sodium bicarbonate. This is the reaction of the phenolphthalein. |
| 00:44:05 | What kind of reaction occurred... after dissolving the sodium bicarbonate and the white substance? |
| 00:44:14 | What happened. Okay then, Kasai-kun. |
| 00:44:18 | The sodium bicarbonate? //turned a light pink. |
| 00:44:20 | //Uh huh. |
| 00:44:24 | It turns a light pink. |
| 00:44:29 | What about the one with the white substance? |
| 00:44:31 | The one with the white substance //turned a dark red. |
| 00:44:33 | //Uh huh. |
| 00:44:36 | It turned a dark red. |
| 00:44:38 | From this information. From this information, it turned a dark red. Then can you, or can you not say that this white substance is the same thing as this sodium bicarbonate? How about it? |
| 00:45:01 | The reactions are... different, so what can you say about them? |
| 00:45:05 | They aren't the same. |
| 00:45:06 | They aren't the same, right? |
| 00:45:09 | So, that means that it turned into a different substance from sodium bicarbonate. |
| 00:45:24 | It means that it became a different substance... from sodium bicarbonate right? |
| 00:45:38 | This is what can be said. |
| 00:45:43 | Okay? So we have three substances come up today right? One is carbon dioxide. |
| 00:45:55 | So, it wasn't sodium bicarbonate. So then, when we checked to see what it was that was left over. One was, one of them was water. |
| 00:46:04 | As for the other one, we don't know what it is but we know that it's something different from sodium bicarbonate. |
| 00:46:12 | So because of these things, it is not a change of state. This shows us that there was a separate change occurring. |
| 00:46:21 | If we organize this a bit, then I think we can say something like this. |
| 00:46:26 | In the case of a change of state. No matter how hard you try, sodium bicarbonate is going to stay as sodium bicarbonate. |
| 00:46:41 | In the case of a change of state it would be sodium bicarbonate. But this time we have- |
| 00:46:51 | Carbon dioxide and... water, and one more thing. Something entirely different. It became a substance that's not carbon dioxide, water, or sodium bicarbonate. |
| 00:47:12 | So now I would like to inform everyone. This substance that's different from this sodium bicarbonate. |
| 00:47:17 | To tell you what we call this substance... I wonder if this name may be a little confusing. This is what we call it. |
| 00:47:30 | In Japanese we call it sodium carbonate. |
| 00:47:37 | If sodium bicarbonate is the base of baking powder, then it turns into a substance entirely different that's this. |
| 00:47:51 | So, this time, in the experiment that you did. Gas was generated, however, that was. Wait. It wasn't... gas generated caused by a... a change of state, but- |
| 00:48:14 | it was a change where this one substance split into three different substances. |
| 00:48:28 | Understand. That's what we found out. |
| 00:48:35 | From this substance. We originally had this kind of substance, and it split into something entirely different. It split into over three substances. This kind of change occurred. |
| 00:48:50 | This is the change that occurred with the sodium bicarbonate due to heating it up. |
| 00:48:58 | And this is not only limited to the base of baking powder, of sodium bicarbonate. There are lots of other ones [that have a similar kind of reaction] in this world. There are a lot. |
| 00:49:08 | In our next class, I would like to show you an example of something that might produce the same kind of change. |
| 00:49:21 | So we confirmed that there are other kinds of changes other than changes of states in this world. So I would like to summarize this in our next class meeting. |
| 00:49:35 | Please ask me if you have any questions regarding today's experiment. |
| 00:49:42 | Please ask any questions. |
| 00:49:52 | Okay then, uh, the bell is going to ring soon so we will give our parting words first. After that //we will clean up. So wash [the tools] off with water and put it back over here where it was. |
| 00:49:58 | //[bell] |
| 00:50:06 | There's a wiping cloth over here so, use the wiping cloth to wipe off your desks please. As for the paper. Use the aluminum foil to cover the sodium bicarbonate please. |
| 00:50:12 | As for the other paper products such as the paraffin paper, uh, I'm going to have a container ready so please put them back over here. |
| 00:50:19 | Okay then we'll clean up, no. We'll give our parting words. |
| 00:50:33 | Stand up. |
| 00:50:43 | Bow. |
| 00:50:46 | Okay, okay please start cleaning up. |
| 00:50:50 | Teacher, teacher. |
| 00:50:53 | Yes. |
| 00:50:54 | What should we do with limewater? |
| 00:50:55 | You can just drain it. You can drain all. |
| 00:50:56 | You can drain all of the fluids away. Return the distilled water okay? |
| 00:51:02 | Teacher. What's this blue thing? |
| 00:51:04 | This absorbs the moisture. It's called silica gel. |
| 00:51:07 | When I put some distilled water on it, //it turned pink. |
| 00:51:09 | //It turned pink right? So it's the same kind of thing as this. |
| 00:51:17 | Teacher, I can't get (inaudible) off. |
| 00:51:20 | Okay then water. Okay then if you can't get if off then forget it. |
| 00:51:26 | I'll wash it again later. |
| 00:51:28 | Can I (inaudible)? |
| 00:51:31 | Yeah, you can throw it away. |
| 00:51:35 | Oh, put that back here okay? |
| 00:51:38 | We're done. It went according to schedule. |
| 00:51:45 | My only complaint is that I was hoping for somebody to clean the blackboard. |
| 00:51:52 | Oh, you can just put the used matches in there as they are. |
| 00:51:59 | Uh, put the papers like the paraffin paper in this garbage over here okay? |
| 00:52:05 | Uh, put this in here. |
| 00:52:12 | You can throw the paraffin paper away. |
| 00:52:15 | Oh, just leave that there. |
| 00:52:29 | Oh, put water in it and just stand it up over here. |
| 00:52:33 | Okay, you can throw it away. You can throw it away. In this garbage can. |
| 00:52:38 | Okay then. Just put it in here as it is. |
| 00:52:40 | There's one over here too. |
| 00:52:41 | No it's okay, just do it as it is. |
| 00:52:42 | Teacher, do we put this in the trash? |
| 00:52:44 | Yes, in the trash. It's right there. It's below Minami-kun. |
| 00:52:50 | Oh, then stand it up here. |
| 00:52:51 | Can I put the limewater down here with the rest? |
| 00:52:53 | Bring them all. Bring them all. |
| 00:53:00 | Hm? The same. Exactly the same. Leave whatever you have left over here. |
| 00:53:15 | Uh huh. You can just throw it away in the trash. |
| 00:53:27 | Okay, if your done, wipe your desks off and you can return to the classroom. |
| 00:53:54 | Okay. |
| 00:53:55 | Uh, why do we hiccup when (inaudible)? |
| 00:54:02 | I don't really know either. Some people say it's because the diaphragm (inaudible) or is cramped. I don't know. |