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.

00:00:08Okay then, let's begin.
00:00:17Stand 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.
00:00:34In a consultation room, Kanno Ayumi-san, and Hoshi Toru-kun are present. Bow.
00:00:40//Okay then, let's begin.
00:00:46I kind of feel a little nervous.
00:00:50Okay 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?
00:01:01Sodium //bicarbonate.
00:01:04Sodium bicarbonate.
00:01:04//Sodium bicarbonate.
00:01:05Sodium bicarbonate is the main substance in here right?
00:01:21And when you make cake, you... heat this up. And then it rose. And what came out to make it rise?
00:01:39Because gas came out.
00:01:41Okay 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.
00:01:50When I asked what kind of gas this was, I received a few candidates. What were they?
00:01:56Carbon dioxide.
00:01:57Carbon dioxide.
00:02:00It could be.
00:02:07It could be. What other possibilities are there?
00:02:12Sodium bicarbonate.
00:02:18Sodium bicarbonate.
00:02:29Sodium bicarbonate.
00:02:31So there is the chance that this sodium bicarbonate directly turned into the gas form of sodium bicarbonate. We don't know.
00:02:39It 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?
00:02:53//Limewater, right? We talked about using this.
00:02:58If the limewater turns cloudy white, then it's probably this.
00:03:03If it doesn't turn cloudy white then-
00:03:12there is a chance that it's this one.
00:03:22It might be something other than carbon dioxide, so if that happens then we'll have to do another experiment.
00:03:28You guys thought that it was carbon dioxide, right? So we want to try and confirm it with this.
00:03:36Let'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.
00:03:45If it doesn't turn cloudy white, then as another possibility it could be sodium bicarbonate that changed its state.
00:03:58There's the possibility that it changed its state. So I think that you can come to your conclusions in this way.
00:04:05And then uh, I've put the experiment confirmation on the handouts so please look at your handouts.
00:04:17And I'd like to confirm the procedure, so please take a look at the procedures. I'd like to begin the preparations now.
00:04:30Uh, 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.
00:04:45And 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.
00:04:54And the test tubes. All you need is one test tube. One is enough. Please take one piece of paraffin paper please. Also one spoon.
00:05:05And there's also a rubber stopper with a glass tube right here, so take one of these as well.
00:05:09Take one of everything.
00:05:11And I'll have some limewater ready here, so I'll have you take that.
00:05:15And 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.
00:05:30And 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.
00:05:59And after you take it with the spoon... put it inside here please. Some of it spilled a little, on the hand.
00:06:09So put in here like this.
00:06:24The 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.
00:06:39If 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.
00:06:47And 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.
00:07:03And 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.
00:07:13And 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.
00:07:24You're also going to turn this off, however make sure that you take this out first. Remove this.
00:07:31If 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.
00:07:41There 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].
00:07:49Make sure you are really careful concerning these two points as you do this.
00:07:53Let's see, are you okay concerning the procedure?
00:07:56Okay then, it's already been prepared for you right here, so I would like each group to prepare and start the experiment, please.
00:08:23This? Is it okay if we take this?
00:08:26Yes, that's fine.
00:08:27The cameraman may have a little cold.
00:08:38Take the one right here.
00:08:54Okay here, take them.
00:08:58If you don't have enough matches then take more from here.
00:10:16Did you get matches?
00:10:17I got them.
00:10:27Teacher, I (spilled).
00:10:28That's okay. Uh, there's a wiping cloth right there. With the wiping cloth. //Will you do that?
00:10:33Teacher, teacher.
00:10:35This is a little too much. I said one light scoop.
00:10:37Teacher, is this about //right?
00:10:38//Uh huh, this is about right.
00:10:39It'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.
00:10:47Teacher, is it not good to put too much in?
00:10:48No. About one scoop with the spoon.
00:10:50Uh huh, one big scoop is fine.
00:10:51One big scoop.
00:11:06We won't need this?
00:11:07Oh, okay then //save it just like this. Just save it like this.
00:11:12Open this up //and.
00:11:14//Murai-san, that's the opposite way. Murai-san, the other way.
00:11:17The other way, the other way. You have to wind it like this. Yes.
00:11:19Murai-san, the other way.
00:11:20Teacher, can we start doing this?
00:11:21Oh, that's fine. //You can start.
00:11:22//Over here!
00:11:24That's about right.
00:11:25Is this about right?
00:11:26That's about right.
00:11:27That's good. That's good.
00:11:31I don't know if we have it or not.
00:11:38Don't overdo it. That's good enough right there. It might be better to bring that more over here a little.
00:11:43Yeah well, I guess that's good enough. That's good enough right here. Okay.
00:11:46If you make it too tight then it might crack right here.
00:11:49Make sure you tighten this part correctly.
00:11:52Daichi, this is next.
00:11:58Uh huh, that's fine. You should do it properly. Make sure that this won't do. All right.
00:12:09Teacher, about this much?
00:12:10Uh huh, about that much.
00:12:17Clamp it.
00:12:18Teacher, how do I make it so this thing goes up?
00:12:21Oh you have to do this a little bit to this part.
00:12:24Teacher, this is kind of sticky. It's kind //of oily.
00:12:27//Uh huh.
00:12:31Is this good enough?
00:12:32Yeah, that's good enough.
00:12:35About this much.
00:12:36Right, right, right.
00:12:38Can I turn it on?
00:12:40The first time is //(likely to fail).
00:12:42//Hey, but is this okay with this one?
00:12:44The position is too high.
00:12:46Okay, okay, okay, okay.
00:12:48It might be better to adjust this after you light it.
00:12:52Okay then, why don't you light it.
00:12:59Teacher, is this okay?
00:13:00Yes. Yes that's fine.
00:13:08It went out again.
00:13:10Why don't you put it in little by little. You have to make it so that you don't get any air in there.
00:13:16The other way, the other way.
00:13:17(It doesn't matter.)
00:13:20Okay, okay, why don't you try it like this.
00:13:47We have a wiping cloth, so just use the wiping cloth.
00:13:56We have a little more.
00:14:04That's so fast.
00:14:06Ohh, this, this.
00:14:13Carbon dioxide.
00:14:21You have to (take some more out) and put it there. That's enough.
00:14:33It's good like this, but why don't you lower it a little more?
00:14:40Uh huh. Good. And this, now put this inside of that.
00:14:56Why, why?
00:14:57It's official. It's officially carbon dioxide.
00:14:59The water came out from here.
00:15:03Nothing, nothing's coming out?
00:15:05Huh? It //came out.
00:15:06//We just did it right now.
00:15:07You did it? Oh, okay, okay. Then you have to take this out.
00:15:11Oh, that's right!
00:15:13Teacher, is this good enough?
00:15:15That'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.
00:15:30Whoa, incredible, it's starting to turn //white.
00:15:35Okay then, for those groups who got a reaction... turn it off without making a mistake.
00:15:49Okay, for those groups who got a reaction.
00:15:52Teacher, the reaction was over already?
00:15:54Hm? Oh, that's good.
00:15:55Hey, 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?
00:16:00What happened? You don't have a match?
00:16:05Take the matches that are there.
00:16:16For 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.
00:17:01Oh, it lit. Okay then, I'll do the rest.
00:17:09Teacher (inaudible).
00:17:13What you think you can derive from the results.
00:17:17Oh, you got a result right?
00:17:19Teacher, teacher. This part won't turn.
00:17:23Oh, really.
00:17:30Oh, it turned.
00:17:31That's fine. Okay then, you can do it like this.
00:17:42Teacher, the thing which built up is-
00:17:44Uh huh.
00:17:45More 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.
00:17:49The //white cloudy stuff is (building up a the bottom)?
00:17:50//What's this white substance?
00:17:52I'll tell you what that is on a separate occasion soon.
00:17:58It gets cloudy white.
00:17:59Since you got this. What kind of change does that mean you got?
00:18:06I have to write it down, right?
00:18:12Okay then, let's do it together later.
00:18:17Teacher, can I write it down below the part where it says results?
00:18:18Uh huh, below the part where it says results. It's the... part for the analysis. Okay?
00:18:32As you heat up sodium bicarbonate-
00:18:51As you heat it up.
00:18:57And, given that gas was produced.
00:19:08Given that gas was produced, how does the sodium bicarbonate-
00:19:18What kind of change... can you say occurred? You can at least say that it's certainly not that one.
00:19:31Then I'll ask you. What kind of gas was this?
00:19:38What kind of gas was //this?
00:19:42This gas was?
00:19:48Okay then you tell me, Amano-kun.
00:19:52Carbon dioxide.
00:19:53It was carbon //dioxide, right?
00:19:56This gas that was produced was carbon dioxide.
00:20:04A gas called carbon dioxide was produced.
00:20:13That'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.
00:20:31What being carbon dioxide means is... that we know it can't be this, right?
00:20:41So, because carbon dioxide was generated, can we say that when heating sodium bicarbonate, did it change or not change its state?
00:20:52You 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.
00:21:05So it is not a change of state. As ice turns to water and water turns to steam.
00:21:11In 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.
00:21:19Something obviously different came out.
00:21:22Okay then, if the change in the sodium bicarbonate was not a change in state, then what kind of change occurred?
00:21:35The fact that carbon dioxide was generated means that it was not a change of state. This is not a change of state.
00:21:54It is not a change of state. Okay. Then what was it?
00:22:01So 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?
00:22:15Did you take them down? For those of you who took them down.
00:22:22Well, 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.
00:22:30Uh, 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?
00:22:46Having looked in the test tube. How is it?
00:22:55I can't tell.
00:22:56Okay, please tell us about what have you noticed.
00:23:01Okay then Soga-kun, say it, will you?
00:23:03It's hardened.
00:23:04It'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.
00:23:24There's some vapor.
00:23:25There's some vapor. Are there some water droplets?
00:23:31There seem to be some water droplets.
00:23:38There 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.
00:23:46So 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?
00:24:04Lick it?
00:24:07Litmus //paper.
00:24:08//Litmus paper.
00:24:13Can we use litmus paper?
00:24:18We 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.
00:24:30What's that?
00:24:34Hm? Do you know what it is? You don't know? Okay then I'll show it to you.
00:25:00Let's see. I want to get one that has a nice color.
00:25:10We have this blue colored thing. And it's not litmus paper but a cobalt chloride paper.
00:25:34If you put it in water... hold on.
00:25:48If you put this in. The color may be a little difficult to see. What color did it become?
00:25:57If 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.
00:26:09There'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.
00:26:18And, 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.
00:26:40And 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.
00:26:53Two, four-
00:28:12Okay, are you ready? I would like to check what the remaining substance is with the method written there.
00:28:20When we just heated up the sodium bicarbonate, at the very least we confirmed that carbon dioxide was generated.
00:28:26And 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.
00:28:42If 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.
00:28:55So 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.
00:29:05Remove that. Leave it removed, and then quickly take this from here with tweezers and then put it on the mouth please. Do you understand?
00:29:18And 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.
00:29:27So if that's the case or not. If it's not, then this will not change.
00:29:32Okay. So now. One more thing. About the substance that was left over on the bottom. The substance that's left over on the bottom.
00:29:41The substance left over on the bottom is... left kind of like this right now. What is this left over substance?
00:29:53You'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?
00:30:15Can you say that this is sodium bicarbonate?
00:30:19We don't know.
00:30:20We don't know.
00:30:21We don't know, right? If we get the same reaction with the same kind of process, then we can say that it's this.
00:30:28So 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.
00:30:38Over here, we're going to stand it up in this way. Well.
00:30:45This hasn't reacted, but stand it up.
00:30:47And 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.
00:31:00And 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.
00:31:18You 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.
00:31:28You'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.
00:31:35And 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.
00:31:44If there are some that don't quite fit too well, then. Wait a moment okay?
00:32:02The amount of water you should put in, should be about one third to one fourth of the test tube.
00:32:16If you put too much in then it becomes difficult to shake.
00:32:22And 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.
00:32:33To 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.
00:32:50One or two drops. Like this. It drops. Please put this in.
00:32:57And 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.
00:33:09Do you understand what you have to do?
00:33:11Okay 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.
00:33:35Kana-chan, do you have that over there? Can you bring that?
00:33:58When 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.
00:34:15Hm, are you missing something? Hm?
00:34:16This //paper.
00:34:17//The cobalt chloride paper? This one.
00:34:25Are we supposed to just take it like this?
00:34:26Uh huh, just take it like that.
00:34:49How did it turn out when you stuck it on the water droplets.
00:34:52It changes.
00:34:54It's pink.
00:34:55Okay then, record that.
00:35:08Teacher, 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.
00:35:15It changed. Okay then, record. Record when you get your results.
00:35:20You got it, right?
00:35:22Okay. Then please record it.
00:35:31Where should I leave this? Here?
00:35:33Oh, it would be fine if you left it around here. Oh, you could just leave it with the paraffin paper.
00:35:38Yeah, that's right.
00:36:17Are you still going to put more in?
00:36:29You say such complex things.
00:36:41I didn't really understand that one.
00:36:51Okay then do it one more time.
00:37:00Will you shake this?
00:37:19Yeah, 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.
00:37:28Uh huh.
00:37:29And then put in the water the same way.
00:37:37Ohh? //well this is also one type of way it dissolves, so...
00:37:38//It won't dissolve.
00:37:48Isn't this kind of pink?
00:37:50Ha, ha, it's kind of (inaudible).
00:37:57Oh, it's starting to dissolve.
00:37:58Oh, it's really pink.
00:38:00Okay, that's good enough.
00:38:03It won't dissolve.
00:38:04Oh, well that's one kind of result as well, right? So it'll be good to record that.
00:38:12Teacher. This (changed colors).
00:38:15Where should we (inaudible)?
00:38:17First of all, did you get a result? Then write your results down. Write your results down and from your results, with these two substances.
00:38:26This hydro-, can you or can you not say that this substance formed is in fact sodium bicarbonate. Write that here.
00:38:31Wait. (inaudible).
00:38:34If it were the same reaction then. This is-
00:38:37Oh, that's right, that's right, that's right.
00:38:38This is the original sodium bicarbonate //right?
00:38:40//Yes, yes, yes.
00:38:41This one's the one we heated.
00:38:44Let's see. This one is-
00:38:50I made a mistake.
00:38:51Who cares because we're going to (throw it away) anyway.
00:38:53Let's put it in a little sooner.
00:38:59Teacher (I spilled it.)
00:39:00Oh, that's fine. It's okay.
00:39:06You 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.
00:39:13A little at a time.
00:39:15You should leave this around here and-
00:39:18I don't know.
00:39:19You should move a little bit and then. Like //this.
00:39:23//As expected!
00:39:24As expected!
00:39:25Let's do it.
00:39:26How many drops would be good?
00:39:29How many drops? I think it's about three.
00:39:34I think it turned kind of pinkish.
00:39:45Uh huh. Was the reaction the same? Was it different? It was different, right? Then write that down in your records.
00:39:50It's changing.
00:39:51It's different.
00:39:57Did you put it in both of them?
00:39:58Yes, we did.
00:40:08Why don't you try putting one more drop in each of them.
00:40:34This isn't it. Is this the one that you put on that side?
00:40:38Okay then, write down the results of this one.
00:40:40It's really different.
00:40:41What a color.
00:40:43It's quite a lot different, isn't it?
00:40:57(inaudible) is important.
00:41:00What that mean is-
00:41:01In that part, that part?
00:41:03It is (inaudible), isn't it.
00:41:05Which one is this?
00:41:10You mean, this test tube?
00:41:31We put too much in it. (inaudible)
00:41:43Uh, which one is the one which is really pink?
00:41:45Okay, write your results please, okay?
00:42:15Okay then. Stop what you're doing for a moment and look up at me please.
00:42:55Okay then, let's start the confirmations.
00:43:09What kind of reaction did the cobalt chloride paper have when you put it up against the mouth of the test tube?
00:43:16Okay, Koga-kun.
00:43:20Uh huh. What kind of, what happened?
00:43:22It turned //red.
00:43:23//It turned red.
00:43:29It 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?
00:43:42Given that this turned red. This is?
00:43:47Okay then, Kimura-kun.
00:43:50It means that it was water, right? What was made here was water. It's been confirmed that it was water.
00:43:56Okay then, we tried putting the phenolphthalein in. And we compared it to sodium bicarbonate. This is the reaction of the phenolphthalein.
00:44:05What kind of reaction occurred... after dissolving the sodium bicarbonate and the white substance?
00:44:14What happened. Okay then, Kasai-kun.
00:44:18The sodium bicarbonate? //turned a light pink.
00:44:20//Uh huh.
00:44:24It turns a light pink.
00:44:29What about the one with the white substance?
00:44:31The one with the white substance //turned a dark red.
00:44:33//Uh huh.
00:44:36It turned a dark red.
00:44:38From 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?
00:45:01The reactions are... different, so what can you say about them?
00:45:05They aren't the same.
00:45:06They aren't the same, right?
00:45:09So, that means that it turned into a different substance from sodium bicarbonate.
00:45:24It means that it became a different substance... from sodium bicarbonate right?
00:45:38This is what can be said.
00:45:43Okay? So we have three substances come up today right? One is carbon dioxide.
00:45:55So, 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.
00:46:04As for the other one, we don't know what it is but we know that it's something different from sodium bicarbonate.
00:46:12So because of these things, it is not a change of state. This shows us that there was a separate change occurring.
00:46:21If we organize this a bit, then I think we can say something like this.
00:46:26In the case of a change of state. No matter how hard you try, sodium bicarbonate is going to stay as sodium bicarbonate.
00:46:41In the case of a change of state it would be sodium bicarbonate. But this time we have-
00:46:51Carbon dioxide and... water, and one more thing. Something entirely different. It became a substance that's not carbon dioxide, water, or sodium bicarbonate.
00:47:12So now I would like to inform everyone. This substance that's different from this sodium bicarbonate.
00:47:17To tell you what we call this substance... I wonder if this name may be a little confusing. This is what we call it.
00:47:30In Japanese we call it sodium carbonate.
00:47:37If sodium bicarbonate is the base of baking powder, then it turns into a substance entirely different that's this.
00:47:51So, 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-
00:48:14it was a change where this one substance split into three different substances.
00:48:28Understand. That's what we found out.
00:48:35From 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.
00:48:50This is the change that occurred with the sodium bicarbonate due to heating it up.
00:48:58And 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.
00:49:08In our next class, I would like to show you an example of something that might produce the same kind of change.
00:49:21So 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.
00:49:35Please ask me if you have any questions regarding today's experiment.
00:49:42Please ask any questions.
00:49:52Okay 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.
00:50:06There'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.
00:50:12As 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.
00:50:19Okay then we'll clean up, no. We'll give our parting words.
00:50:33Stand up.
00:50:46Okay, okay please start cleaning up.
00:50:50Teacher, teacher.
00:50:54What should we do with limewater?
00:50:55You can just drain it. You can drain all.
00:50:56You can drain all of the fluids away. Return the distilled water okay?
00:51:02Teacher. What's this blue thing?
00:51:04This absorbs the moisture. It's called silica gel.
00:51:07When 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.
00:51:17Teacher, I can't get (inaudible) off.
00:51:20Okay then water. Okay then if you can't get if off then forget it.
00:51:26I'll wash it again later.
00:51:28Can I (inaudible)?
00:51:31Yeah, you can throw it away.
00:51:35Oh, put that back here okay?
00:51:38We're done. It went according to schedule.
00:51:45My only complaint is that I was hoping for somebody to clean the blackboard.
00:51:52Oh, you can just put the used matches in there as they are.
00:51:59Uh, put the papers like the paraffin paper in this garbage over here okay?
00:52:05Uh, put this in here.
00:52:12You can throw the paraffin paper away.
00:52:15Oh, just leave that there.
00:52:29Oh, put water in it and just stand it up over here.
00:52:33Okay, you can throw it away. You can throw it away. In this garbage can.
00:52:38Okay then. Just put it in here as it is.
00:52:40There's one over here too.
00:52:41No it's okay, just do it as it is.
00:52:42Teacher, do we put this in the trash?
00:52:44Yes, in the trash. It's right there. It's below Minami-kun.
00:52:50Oh, then stand it up here.
00:52:51Can I put the limewater down here with the rest?
00:52:53Bring them all. Bring them all.
00:53:00Hm? The same. Exactly the same. Leave whatever you have left over here.
00:53:15Uh huh. You can just throw it away in the trash.
00:53:27Okay, if your done, wipe your desks off and you can return to the classroom.
00:53:55Uh, why do we hiccup when (inaudible)?
00:54:02I don't really know either. Some people say it's because the diaphragm (inaudible) or is cramped. I don't know.