This eighth-grade science lesson is about chemical reactions, and more specifically, the decomposition reaction of sodium bicarbonate. It is the third lesson in a sequence of 18 lessons on chemical changes. The lesson is 55 minutes in duration. There are 35 students in the class.

00:00:02Teacher, can I (inaudible)?
00:00:06No, Yoshi-kun. Let's begin.
00:00:11Masa-kun, please.
00:00:12Stand up.
00:00:21//Please pay attention.
00:00:26Today, we ask Ms. Yasui to help us. Where is the white chalk?
00:00:34Do you remember we did a survey the last time? Watch on the board.
00:01:05Today everyone is very-
00:01:07OQuiet, aren't they?
00:01:08Very quiet. I've only experienced such quietness 2,3 times. Then everyone please read today's theme. One, two.
00:01:20That's what I asked you the last time, right?When I asked enamel wire-Miso soup-
00:01:22Refill lead of a mechanical pencil, things like that, your answers were clearly divided unexpectedly with these three items.
00:01:54I would like to confirm it again.
00:01:58Enamel wire, miso soup, refill lead of a mechanical pencil. I will demonstrate an experiment now.
00:02:03Will they generate heat? Raise your hand for the item which you think will generate heat. //Okay?
00:02:08//How many times can I raise my hand?
00:02:09If you think all three will, then you can raise your hand three times.
00:02:13Enamel wire. This. Enamel wire.
00:02:19You must have made electromagnets in elementary school. It's the conducting wire which you wound at that time.
00:02:26Then miso soup. Today, I will use one with red bean paste. Miso soup with read bean paste.
00:02:27Can we eat it?
00:02:28Yes. If there are leftovers, I will give it to Masa.
00:02:32And some refill lead of a mechanical pencil.
00:02:35Then I will ask you. Okay? Then who thinks that the enamel wire will generate heat?
00:02:42One, two, three, four, five, six, seven, eight, nine, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23. Okay. Twenty-three.
00:02:53Miso soup. Miso soup with read bean paste.
00:02:56Only with read bean paste?
00:02:57One, two, three, four, five, six, seven. Okay.
00:03:01That has a lot of sodium.
00:03:03Then the lead of a mechanical pencil.
00:03:05This is serious.
00:03:06One, two, three, four, five, six, seven, eight, nine, 10, 11, 12. Okay.
00:03:11Then. Can anyone tell that it is certain from your own experience? Anyone?
00:03:18From your own experience, since you have done it before. Can anyone tell for sure?
00:03:23Haven't you done it before?
00:03:24Oh, the lead of a mechanical pencil... //the lead of a mechanical pencil-
00:03:27Yes, Matsui-kun. Yes. Please stand up and speak.
00:03:31Look at the camera.
00:03:32Oh, no.
00:03:33What? What?
00:03:35I don't know, but the teacher of shop class-
00:03:39Stand and speak.
00:03:41Stand up and speak.
00:03:42It conducts electric current.
00:03:43The teacher of shop class said so.
00:03:44Said so.
00:03:45Said so. That's fine. You can sit down.
00:03:48Then lead of a mechanical pencil. These 12 people may be right. Anything else? Do you have experience?
00:03:53No? Then should we experiment in order? Then first we'll do it with an enamel wire.
00:03:57Since it is hard to see my operation, Ms. Yasui will project it on that TV. But come to the front as usual. Please.
00:04:18Can people in the front squat down?
00:04:23If you cannot see it, you can watch the monitor. Then a little bit-
00:04:30Murai-kun, you are the assistant. Please hold this.
00:04:36So everyone can see the thermometer. Can you see what the temperature is now?
00:04:40It won't reach all the way.
00:04:41Oh, it won't reach?
00:04:43This one-
00:04:44What is the temperature?
00:04:47Eight degrees, right? Right now it's eight degrees. Then now I will make an electric current flow through this.
00:04:51Here, at the tip of the thermometer, I have wound the enamel wire. If it generates heat, the thermometer will indicate it.
00:05:02Ouch, ouch. Ouch.
00:05:07Watch this. Oh, it is disconnected.
00:05:11Wait. Okay. Watch. It is increasing, right?
00:05:15It is.
00:05:16What is the temperature now?
00:05:21It was only eight degrees before, but it's already seventeen degrees.
00:05:23It's already about 20.
00:05:24It's still rising. Yes. It's almost 20.
00:05:26It's rising more and more.
00:05:27I am getting an electric shock.
00:05:28I am not getting it at all. See?
00:05:31It's already 25. Should I show it to you? Look at the monitor.
00:05:36Where is it?
00:05:38Teacher, where is it?
00:05:41Can you see that it has increased?
00:05:45It's increasing more and more.
00:05:46Did it increase?
00:05:47It's increasing.
00:05:48This means that?
00:05:49It's increasing.
00:05:50It's increasing.
00:05:51It's increasing, right?
00:05:52Why don't you do it putting this down?
00:05:54It's already 30 degrees.
00:05:56Next, next.
00:05:57It increased so much.
00:05:58It increased so much. It was eight degrees, so how many degrees did it increase?
00:06:01Twenty-two. Very well.
00:06:03That means that an enamel wire is fine. It generates heat. Then next let's do it with miso soup. Miso soup.
00:06:11Do we do all of this?
00:06:13Miso soup is here, here.
00:06:16I don't like it somehow.
00:06:17I don't like it.
00:06:18This is a present far you, Matsui-kun.
00:06:20Far you?
00:06:21Far you?
00:06:24She spoke incorrect English.
00:06:25Her English is incorrect.
00:06:27You spoke incorrect English.
00:06:28It's okay.
00:06:29OShe is a science teacher.
00:06:30She spoke incorrect English.
00:06:35Then we use this aluminum foil as an electric pole and put this in the beaker.
00:06:41You can leave it here.
00:06:44Teacher, aren't you going to give me the one which is in the bag?
00:06:47This one, right? I will give it to you, Matsui, so don't worry. Okay?
00:06:53I put another electric pole here.
00:06:59There is something in the miso soup.
00:07:01Oh, that's true.
00:07:02Seaweed is in there.
00:07:05Don't worry about my cooking.
00:07:12Right now... it's five degrees. Five degrees. Five degrees.
00:07:19Now I will connect this to the power source.
00:07:29Can you see?
00:07:30Can you see the inside of the miso soup is moving as soon as the switch was turned on?
00:07:38The temperature is rising. The temperature is rising.
00:07:40It's rising, right?
00:07:42It's rising, it's rising.
00:07:42//Can you see?
00:07:43//I was right. I was right. I was right. I was right.
00:07:45I will put it in the front.
00:07:48Can you see? Imai-kun, is it on?
00:07:52Is it on?
00:07:55Something is brewing.
00:07:56Is steam generating? It's also bubbling. What is the temperature now? What is the temperature now?
00:08:04Now 20 degrees. It was five but it went up 15 degrees.
00:08:07Bubbles are oozing.
00:08:09Are bubbles oozing?
00:08:11Try to touch it. It's warm.
00:08:13Hot. Not hot. It's warm.
00:08:15It's warm, right? Touch it.
00:08:19It's warm.
00:08:22It doesn't taste good.
00:08:23What is the temperature now?
00:08:27Teacher, that's no good.
00:08:28Forty degrees.
00:08:29It's rapidly increasing.
00:08:30It's stinks.
00:08:31Is this about right to drink?
00:08:34Fifty degrees.
00:08:35Fifty degrees? Then, Masa-kun, it's perfect to drink now.
00:08:40This means?
00:08:44Miso soup is also?
00:08:45It's burnt.
00:08:47This bubbles-
00:08:48Okay. Then, next, at last, shall we do it with the lead of a mechanical pencil?
00:08:54This got very hot. It will break.
00:08:56It will break? Stop it.
00:08:59Then next is the lead of a mechanical pencil.
00:09:03Then first, since I had some steel wool, I brought it. This one I think everyone can see well. I will do it with the steel wool as well.
00:09:20After I set it here.
00:09:27That's fine. The connection is not good.
00:09:29Oh, it's burning.
00:09:30Hot, hot, hot!
00:09:34It's burnt out! It's burnt out!
00:09:36Hot, hot! It's burnt out!
00:09:38Did you see that it burnt?
00:09:41What is that, teacher?
00:09:42This is steel wool. Right now, it's about two volts.
00:09:48Zoom up more.
00:09:54It's already burning. Steel burns. That means that it generated heat.
00:10:01Then, //at last, the mechanical pencil.
00:10:04//In short, you just brought something which generate heat, right?
00:10:05Of course.
00:10:07I knew it.
00:10:08There is something which generates heat here.
00:10:17Then I will do it with the mechanical pencil.
00:10:37Oh! Acid rain!
00:10:39It started smoking. It started smoking, so wait for a while.
00:10:49People in the front, be careful. It may jump.
00:10:54I'm fine because I'm wearing glasses.
00:10:57Then I will increase the voltage. Right now I am increasing the voltage.
00:11:03Something is changing a little.
00:11:06Oh, it became red! It became red!
00:11:07Not a little bit. A lot.
00:11:09If you touch it, you will burn yourself.
00:11:11You won't burn yourself.
00:11:13This means that the lead of mechanical pencils also?
00:11:15Conducts heat.
00:11:16Yes, it generates heat, right?
00:11:18It conducts heat.
00:11:20Rather, it means that it conducts electric current, and generates heat.
00:11:24It's bent.
00:11:27It got thinner.
00:11:28When it conducts heat?
00:11:29Can you use the lead?
00:11:31It already got so thin.
00:11:34Then go back to your seat.
00:11:50Almost anything will generate heat when current flows through it.
00:11:59That is what I showed you with electric discharge when we studied electric current and electrons. The flow of an electric current means the electrons are flowing.
00:12:07Because the electron flow bumps atoms of the material, when they bump with atoms, it generates heat.
00:12:18So today, the amount of heat generated, we will measure through an experiment the amount of heat that is generated.
00:12:25What is this heat related to? As I just showed you, first, we increased the voltage, right?
00:12:35So, it is probably related to the voltage. And if you increase the voltage, logically, what flows a lot?
00:12:46Current flows, right?
00:12:47So today, we will investigate through an experiment how heat increases in relation to the value derived from voltage times current.
00:13:01Then look at the OHP.
00:13:04Ms. Yasui is giving you some worksheets like this now.
00:13:11Today, you will confirm through an experiment that heat generated by electric current is related to the value of voltage times current.
00:13:20I will explain to you how to do it. I think now you got the worksheet, but first set up the equipment like this figure.
00:13:32It doesn't show in this figure, but I think it will be good if you prepared a stand like this.
00:13:37Then I will explain to you how to set up. First, in order to measure the amount of heat-
00:13:45Are you okay? Could you keep looking at this? Watch the OHP. First, set up the thermometer. And hang the thermometer about in the middle of the water.
00:13:57And in order to measure the voltage and the current, take a voltmeter and a ammeter.
00:14:02The power source to use today is this power source. The container to put it in is this polystyrol container, so it will melt if it touches heat, right?
00:14:14So the electric heating wire that generates heat, today we use this but when you put it in, make sure it doesn't touch the bottom or the side.
00:14:26It may melt. So you hang a thermometer, but someone should be responsible and hold this heating wire with their hand. It won't hurt you.
00:14:35And the water will get warmer by the convection current, stir once in a while and measure the temperature. And-
00:14:43Ammeter is in series circuit, voltmeter is in a parallel circuit, the tip is sticking out, so connect the clips here. Two each.
00:14:53And, please measure the temperature of the water before you start.
00:14:58When you did the survey the last time, I found that you forgot how to calculate heat energy.
00:15:03But when you calculate heat energy, the amount of heat that was generated by this electric heating wire is the same as the value which the water receives.
00:15:12So in order to calculate heat energy, the mass of water in this container multiplied by the increase in temperature.
00:15:23In order for everyone to have the same amount of water, I have measured 100 grams and put in there today. Okay?
00:15:30I have prepared 100 grams of water here which has been measured, so please take it from here. The thermometer is also in there.
00:15:40And uh... each group read the value of the current with specified voltage.
00:15:46And the number of increased temperature will be measured after five minutes. Since we have a limited time, I have a stopwatch and everyone will start at the same time.
00:15:58So please tell me when your group finishes setting up the equipment and are ready. When everyone is ready, we will measure five minutes.
00:16:04Now, since every group will measure with a specified voltage, can you please write the voltage here? Here.
00:16:16First these three rows, no, these three groups. These three groups, please do it with three volts and six volts. So here, write three volts and six volts.
00:16:26Then, this row, write three volts and six volts in here.
00:16:29This row, write three volts and six volts.
00:16:32Then these two groups in the middle, write four volts and eight volts. And people over there, please do it with five volts and seven volts.
00:16:43Do we adjust to seven volts?
00:16:44Yes. Please adjust seven volts with the voltmeter precisely.
00:16:49Five volts and?
00:16:51Five volts and seven volts.
00:16:57Then, I will explain to you again. Face this way.
00:17:01For example, these groups have three volts and six volts here, right?
00:17:06During the experiment, this group will give three volts of voltage at the same time as everyone and measure five minutes.
00:17:12Read the ammeter, and see how many amperes it is. And after five minutes, write how much temperature increase there was.
00:17:21And this part was to compare the values of voltage times current, so these three volts-And if this is zero point two amperes, for example, three times zero point two and this becomes one point five volt-amperes.
00:17:34And as for heat energy, you calculate mass of the water times temperature increase. Okay?
00:17:41When you are done, you will have an OHP sheet which Ms. Yasui will give to you. OHP sheets look like this.
00:17:49This graph is to record the relationship between the value of voltage times current and the number for increased temperature of the water.
00:17:56And as for this one, please record the relation between the value of voltage times current and the amount of heat generated.
00:18:02And when you record, just mark dots like this one. This group will have values for three volts and six volts, right?
00:18:11This group will have values for four volts and eight volts, right? This group will have values for five volts and seven volts, right?
00:18:17When everyone is ready, when we stick these sheets together-The relationship between the value of voltage times current and the number for increased temperature of the water or the amount of heat generated,
00:18:28Will appear nicely as dots. So we should be able to infer the relationship between them. Okay? I spoke fast, but did you understand the procedure?
00:18:37We will come over when you are not sure. What you have to prepare is the electric heating wire, here. Voltmeter and ammeter.
00:18:45Take the power source from there as usual. And each group take two cups, okay? We measure twice, okay? For three volts and six volts.
00:18:56So prepare those although we use one of them first. Do you have any questions?
00:19:03You don't? Then each group, get ready.
00:19:10Stands are over there.
00:19:27Sorry, sorry.
00:19:30I have to put the thermometer for the miso-soup as well.
00:19:42You need two cups. One for five volts and another for seven volts.
00:19:45You must change.
00:19:48You told me I have to do well.
00:19:50I told you to do well during the experiment.
00:19:55Isn't' this (inaudible)? Don't touch it.
00:20:00Teacher, the thermometer too?
00:20:01The thermometer too.
00:20:03Do I need (inaudible)?
00:20:05Should I take this?
00:20:06Don't drop it.
00:20:15Wasn't there enough?
00:20:19OHow many were there?
00:20:20There must have been eight.
00:20:26Should I do it with this group? OHP needs to be marked clearly so please write with this. Then first set up.
00:20:37When you are done setting up, everyone starts together.
00:20:44Isn't it better to hang it in this side? It is unstable.
00:20:55Hang it so that it will be in the water.
00:21:01Teacher, this?
00:21:02About five minutes.
00:21:03The spring-like thing.
00:21:04Oh, electric heating wire?
00:21:06Huh? There should be eight. Sorry, did anyone take two heating wires? There should have been eight of these.
00:21:16Oh, you took too many, okay, okay.
00:21:18Here they are.
00:21:29Put the thermometer in the cup and set it up.
00:21:33No, from the side.
00:21:34Yes, yes. You measure the temperature of the water first. This is unstable, so from this side.
00:21:46Since we want to measure the temperature of the water first, please hurry up and set up the water.
00:21:56After hanging it, support it with your hand.
00:22:04Kawai-san... Here, it's your turn, Masago.
00:22:07You have to hold this one like this.
00:22:09Yes. That's why you should hang the thermometer.
00:22:15Masago-kun, you turn that so that you can hang the string.
00:22:31Why don't you put it here?
00:22:58And set it in a series circuit. Which one is positive?
00:23:04This one, right? Yes, yes.
00:23:10This one is negative, right? And this one is positive.
00:23:14This one, this one.
00:23:21This one may fall off.
00:23:22That's fine.
00:23:24Yes. Then please wait if you finished setting up.
00:23:27If you are behind in setting up, I will help you.
00:23:33Should I help you? Are you finished setting up?
00:23:35Is this okay? (inaudible)
00:23:38Oh... milli ampere is hard to see, so leave it as a bigger ampere.This one, you can leave as fifteen volts, since we didn't predict how much current will flow yet.
00:23:49Are you done?
00:23:52Set the ammeter in a series circuit.
00:23:58Plus five amperes, right? And this one? This one is positive, so connect the negative here. And put this one here.
00:24:13Are you done?
00:24:22Why don't you do it from the side? Like this. This clip is dirty so it may be better to change it.
00:24:33This is a clean one.
00:24:35Here you are. Please someone hold it. Here you are.
00:24:42Then record the original water temperature when you are done setting up.
00:24:46Record the original water temperature.
00:24:53Are you done setting up? Hurry up and set up, since everyone is waiting for you.
00:24:59How many volts should we have first?
00:25:06Five amperes.
00:25:07You have to connect one to the ammeter. Is this positive? Then put this to the positive.
00:25:21And this?
00:25:27Should we put this to here then?
00:25:30Mei, the ammeter is not connected.
00:25:36This one goes to positive. This one. This one is positive, Mei. Here. And... Bring this to here. Bring the five-ampere terminal to here. One more, one more.
00:25:51Are you done? Yamase-kun's group, are you done? Okay?
00:25:55Then we will start five minutes from now. Set the first voltage with the voltmeter.
00:26:07Then we will start.
00:26:10First we do it with four volts.
00:26:11First, set it to your voltage.
00:26:13If you do it with three volts and six volts, start with three volts first. If you do it with four volts and eight volts, start with four volts.
00:26:18If you do it with five volts and seven volts, start with five volts.
00:26:22You adjust with the voltmeter, you know?
00:26:23It's this one, right?
00:26:24Yes. Read with the voltmeter. Not that one. Read it with the voltmeter. Anyone that doesn't understand?
00:26:39Ms. Yasui, are we ready?
00:26:44Ms. Yasui, are we ready?
00:26:49Ready? Then we will do it for five minutes. Okay?
00:26:57Yes. Are we ready? Ready? Then ready, go!
00:27:04Then, put in the water.
00:27:08OWait, wait.
00:27:10We cannot wait.
00:27:12Stir sometimes. Stir sometimes, please.
00:27:21Read the voltmeter now.
00:27:25It was hot.
00:27:27You are doing it with four volts, right? Does it say four volts?
00:27:32You have to adjust it to four volts.
00:27:33Huh? We adjusted it before, didn't we?
00:27:34Did something move?
00:27:38The current is not flowing.
00:27:39Is there some part which is disconnected?
00:27:44Let's turn it off once.
00:27:46Was it okay before?
00:27:48Yes, it was.
00:27:50Did it short circuit?
00:28:02Are the positive and the negative okay?
00:28:05This is positive, so this is positive. This one is negative. This is correct. Then should we do it again?
00:28:13That side-
00:28:14It's not increasing.
00:28:15It's not increasing, is it?
00:28:24Why is it not increasing?
00:28:31A little bit.
00:28:33Can I disconnect it once? I will (inaudible).
00:28:41Your group was supposed to do it with four volts and eight volts, right? Then you can start next with eight volts.
00:28:48It starts from positive and-
00:28:54It starts from negative and-
00:28:57This one, right? It goes from positive and here, right?
00:29:00And put the positive of the voltmeter here.
00:29:08Teacher, it is not good if this and this are touching, is it?
00:29:11Yes, it's better if it's not touching.
00:29:13They are touching.
00:29:14Then let's try now.
00:29:17It's not going up yet?
00:29:18It's not going up.
00:29:19Why is that?
00:29:20The voltmeter is working. How about the ammeter? The ammeter is not working either.
00:29:34Nothing is wrong with the power source.
00:29:40Did it touch the heating wire by mistake?
00:29:51It went up.
00:29:52It went up? Then the connection was wrong, since you pulled these so they were not connected well. (Inaudible) Then, it's too bad, but you do it with eight volts.
00:30:04I was worried.
00:30:05Next one, right?
00:30:06Yes, you can do the next one.
00:30:09You can get the data from the neighboring group.
00:30:14Did it work?
00:30:15OVoltmeter was working till just now.
00:30:18We have problems.
00:30:19Mr. Cameraman, we have problems.
00:30:25Did you connect correctly?
00:30:30Oh, it went up.
00:30:32It went up fine.
00:30:34OIt went up? Oh it went back?
00:30:37Move this one too.
00:30:38It's too much.
00:30:39How many volts are you suppose to have?
00:30:40Five volts.
00:30:41Not yet, not yet.
00:30:43Little less, little less. Stop.
00:30:44Did it work?
00:30:45Yes, it did work.
00:30:46Then you start with the next seven volts also.
00:30:50Since these five minutes have already started. Okay?
00:30:53OTeacher, was something wrong with that part?
00:30:54This part was bent, so I think the connection inside was not good.
00:30:55OOh, I see.
00:30:59Don't bend here. If you bend this, Yamase-
00:31:02We didn't do it.
00:31:04Why me?
00:31:05Yes, yes.
00:31:08Then, next you can measure the seven volts well, right? Then get the data from your neighboring group.
00:31:19Stir it sometimes.
00:31:25Thirty seconds more.
00:31:29Thirty seconds more.
00:31:34That's fine. It's three volts, right? Then zero point six amperes, right?
00:31:39Calculate here now. It's three volts times zero point six amperes, so how much?
00:31:46You can calculate in your head.
00:31:49One point eight.
00:31:50Yes, one point eight... volt-amperes.
00:31:57Then... write volt-amperes.
00:32:03Now, measure the temperature. How many degrees did it increase from the original temperature?
00:32:07Can you take turns?
00:32:13You guys... You (inaudible).
00:32:22Then please write how many degrees it has increased.
00:32:27Then we will do the next one. Change the cup.
00:32:31Thirty degrees Celsius. Then what about this one?
00:32:36Change the cup. We will do it for the next five minutes.
00:32:39Is 30 the number that increased?
00:32:40It increased from seven to 37, right?
00:32:45Then your group is doing it with six volts, right? Six volts next, right?
00:32:53While the thermometer settles down, you can calculate heat energy. In order to make the thermometer settle down, calculate heat energy.
00:33:00I forgot how to calculate heat energy.
00:33:04OTurn off the power source.
00:33:10Next you will increase the voltage, so I think it is better to increase the ampere too.
00:33:17Wait until the water temperature is settled.
00:33:19Water mass was 100 grams.
00:33:20One hundred grams?
00:33:23One hundred times the number of temperature increase-
00:33:24Wait a minute. It wasn't 37. It was 47.
00:33:26Your group only had a little increase?
00:33:29Well, that's fine. That is your result. How many amperes was the current?
00:33:34How many amperes was the current at that time?
00:33:37It increased around here first. Was it around here? One hundred, around here?
00:33:44How many?
00:33:46Uh... zero point five.
00:33:50Was it zero point five? Then write here zero point five amperes.
00:33:57Then, this was voltage times current, so three times zero point five.
00:34:04Three times zero point five.
00:34:14Zero point five is half. So what is half of three volts?
00:34:18One point five.
00:34:19One point five, right? One point five.
00:34:24Read this, "volt-ampere."
00:34:27Do I write it like this?
00:34:29And write a dot here since this is multiplication.
00:34:32Then what about the amount of heat generated? It increased two degrees right? Then the water was 100 grams originally, so 100 times increased two degrees-
00:34:40How many calories? One hundred times two equals?
00:34:44Two hundred.
00:34:44Yes, 200 calories. Do it like that.
00:34:52How do you read current ampere?
00:34:54You have to read it as volt-ampere.
00:34:56//Teacher, this is twelve point five-
00:34:57//Three times... your current was twelve point five amperes?
00:35:01Is this 15?
00:35:03That's voltmeter. How about the ammeter?
00:35:05Huh? //Isn't this ampere?
00:35:07//This was twelve point five amperes?
00:35:09It was three.
00:35:12This was, right? You wrote twelve point five. Was the current really //twelve point five?
00:35:15//No, it was three.
00:35:18It was wrong, right?
00:35:19No, it wasn't.
00:35:20This is a ammeter, so-
00:35:22Ouch. How much?
00:35:25It can only measure up to five amperes, so it cannot be possible to measure twelve point five amperes.
00:35:28What we measured was three and six.
00:35:30That's voltage. I'm asking about the electric current. Was the current flow twelve point five amperes?
00:35:37The ammeter. //Did twelve point five amperes flow?
00:35:39//She is asking how much current flowed.
00:35:44We adjusted this before, didn't we?
00:35:45Only three amperes flowed.
00:35:47No, no. What I am saying is that you adjusted the voltmeter to three volts, right? At that time, //the ammeter-
00:35:51//We didn't.
00:35:56What did you adjust to three volts then? This is a ammeter.
00:36:04This is the voltmeter.
00:36:13But nobody noticed.
00:36:14Nobody noticed?
00:36:17Teacher (inaudible), didn't she?
00:36:19No, I said adjust it with this one.
00:36:22Did she say that?
00:36:23This data... I thought the temperature went up too much.
00:36:29Since you cannot use this data, start with six volts.
00:36:33Oh, no.
00:36:34We, we were holding this all the time. We were holding it. And at the certain point-
00:36:39This is a ammeter.
00:36:41Do we have to adjust with this one?
00:36:42Unless it is voltmeter, you cannot measure voltage.
00:36:47Well then, we will start the next experiment.
00:36:52Then please read the thermometer.
00:36:57Then we will start. Okay? Measure voltage with voltmeter. You cannot measure it with a ammeter. We will start.
00:37:11We will start. Ready.
00:37:13Teacher, teacher, wait a second.
00:37:15Should I wait a little bit?
00:37:16Four more minutes.
00:37:22This is wet.
00:37:23What are you doing?
00:37:24What are you doing?
00:37:26Hold it with your hand, don't be lazy. You are making everyone wait.
00:37:32Hurry, hurry. Put it down, put it down.
00:37:36The group over there. Did you read the thermometer?
00:37:39Of course.
00:37:40Yoshikawa-kun, did you read the thermometer?
00:37:42We are reading it right now.
00:37:44Can I raise this to here?
00:37:46That's fine. Don't worry about it.
00:37:52Oh, no. That group is-
00:37:54I will start. Ready? Go.
00:37:57Ready, go.
00:37:58Voltage should be six, right?
00:38:00Six, six, six.
00:38:05This should be eight voltage this time, right?
00:38:09Bubble is oozing.
00:38:10That's fine.
00:38:12Is it okay?
00:38:13Stir it once in a while.
00:38:22Don't make a mistake this time. Oh. Oh.
00:38:26This one is one point five, right?
00:38:28Only five amperes, right? Yes.
00:38:29Five amperes?
00:38:30Five amperes?
00:38:32This means it is one point five volts.
00:38:34Why did you mix up a voltmeter and a ammeter again? We did it so many times... Oh well.
00:38:39Because the color is blue and green.
00:38:41Then multiply this current and this voltage.
00:38:44Five times six equals 30-
00:38:48Sixteen, 18-
00:38:53Nine, right?
00:38:57This time do it well, okay?
00:39:00Don't worry, since that group made mistakes, your group's two degrees increase is just about right.
00:39:08Sometimes people make mistakes.
00:39:10But I think this is unusual.
00:39:20Then while you are waiting for five minutes, put dots for the previous data in the graph on an OHP sheet.
00:39:32Should I tell you how to use this?
00:39:37In the beginning it was one point eight, right? One point eight, this is two. When it is one point eight, the temperature increase was two. So, here?
00:39:47Next, if it generated 200 calories, when it is one point eight, it is 200, so it goes here, right? You just put a dot here with a small circle.
00:39:55The next one is the same way. Just put a dot. Okay?
00:39:58Just dots?
00:39:59Yes, just putting dots is fine.
00:40:01Then watch it carefully so that you won't make a mistake next time. The next data is with nine, right?
00:40:05Since you will have only one dot, this is voltage multiplied by current, you will see how many degrees it increased after five minutes.
00:40:13At that time, draw a point here. When you calculate heat energy, in the same way, nine, here, right? What is the amount of heat generated when it is nine? Put a dot.
00:40:23How do we calculate heat energy?
00:40:24The amount of heat energy is mass of water multiplied by temperature increase.
00:40:27Teacher, when I calculated it with the previous data, it became 3,000.
00:40:30Three thousand.
00:40:31Is the mass of water 100?
00:40:32Yes, today it was 100 grams.
00:40:35The number of increased temperature is 30-
00:40:37But your group applied a fairly high voltage because in order to ten? three, three amperes.
00:40:50Oh, this one, right? It became one point five, right? This one goes two, four, six; so one point five is around here, right?
00:40:56And then the number of increased temperature is two, right? Around here. So put a dot around here.
00:41:03Next is the same way. When it is one point five volt-ampere, it is 200 calories, right?
00:41:07Since this side is for heat energy, so when it is one point five, circle at 200 calories. Okay?
00:41:18How is it? You have only one datum. Then, first multiply current and voltage, first. Eight times one point three.
00:41:29How much is it, Hirai-kun.
00:41:31Ten point four.
00:41:32Ten point four. He said ten point four.
00:41:34Ten point four.
00:41:37Then, you draw the number of the temperature increase after five minutes, right? And for calculating heat energy-
00:41:44Since the heat that was given by the electric wire is the same as the heat that was received by the water-
00:41:47The mass of the water is 100, right? And multiply the number of the temperature increase and get the amount of heat. Okay?
00:41:55And when you write it in here, it is ten point four. This is 10 and 12, right? Find where ten point four is.
00:42:02And put the dot in here at the temperature increase.
00:42:06Imai-kun has suspicious eyes.
00:42:08In the same way, put a dot to indicate the amount of heat energy when it is ten point five. Did you understand? There is only one datum, so do it precisely.
00:42:22Were you explained how to draw the graph? Okay?
00:42:27This is big.
00:42:29That's fine. Big is fine.
00:42:32Twenty more seconds.
00:42:35Get ready to read the thermometer.
00:42:37Well, now it's 16 degrees//
00:42:39//(inaudible) get ready to write//
00:42:40//this is 16.
00:42:41Did you put dots?
00:42:45Where? Oh, I cannot see it. Draw it clearly.
00:42:50This one? You got six point five, right? It's six point five, so is it about here?
00:42:57Then read the next temperature.
00:42:58It's over.
00:43:01It increased four degrees, right? So it's four, yes, yes.
00:43:08We are done.
00:43:10How many degrees have increased?
00:43:11You know, right?
00:43:12That's why it's one point six.
00:43:14It's 14, I heard.
00:43:17Fourteen. Thirteen.
00:43:21Did it increase 11 degrees?
00:43:24This one is the number of increase, so you have to write four for this.
00:43:26Oh, I see.
00:43:31Yes, yes. And this... you draw a circle, but this is for calorie.
00:43:35Oh, calorie.
00:43:44Then, when you draw on the sheet, bring it to me.
00:43:50It's ten point five. Is it around here?
00:43:53Make sure to turn off the power source.
00:44:00When you are done with the sheet, bring it to me.
00:44:04ODraw it with this pen.
00:44:07Where? Here?
00:44:10ODraw it bigger.
00:44:21Then next. Next is?
00:44:24The size is different.
00:44:27When you finished the sheet, bring it to me.
00:44:30Should I make it thicker? Like fat people. It is clearer in this way. These are so reserved. Then I will take this. Thank you.
00:44:43When you are done, please bring it to me.
00:44:54Are you done? Oh this was yours.
00:44:57Bring the sheet quickly please.
00:45:02The group who turned in the sheet, please look at the OHP.
00:45:13Is this okay just like this?
00:45:14That's fine. We will stick them.
00:45:34Did everyone turn it in?
00:45:36OSix point five and 400 degrees.
00:45:42The group who turned it in, please watch this.
00:45:45OAround here.
00:45:47Thank you for bringing it to me.
00:45:48OThen... eleven point two and eight degrees. Eleven point two is eight degrees.
00:45:54Eleven point two.
00:45:56OThen eight degrees.
00:45:59One more group?
00:46:08Kaji-kun, please take it.
00:46:14Thank you.
00:46:22Then, let's take a look.
00:46:27I stuck all of them together. Then the result of your measurement became like this. So should I draw a line?
00:46:38May I borrow your ruler?
00:46:45This... when the voltage and the current are both zero, there is neither temperature nor heat energy. Here. Origin, okay?
00:46:56Then I will draw a line so that it is close to all the dots.
00:47:09Oh! Amazing! They are exactly on the line!
00:47:11Yes, some are exactly on the line.
00:47:13That means-
00:47:17What can we say from this?
00:47:19This is amazing.
00:47:24Voltage times current equals... what kind of relationship is there in relation to temperature increase and heat energy?
00:47:47What is it? One more time?
00:47:50It has a proportional relationship, right?
00:47:59We found that heat energy is proportional to the product of voltage and current.
00:48:06Then using this result, please try to solve this question.
00:48:11Okay? Heat energy is proportional to the product of voltage and current.
00:48:19Then, this question.
00:48:24This one is a parallel circuit combining a big resistance and a small resistance. This one is a series circuit combining a big resistance and a small resistance.
00:48:39Then in this parallel circuit, which one produces more heat? This one or this one? In a series circuit, which one produces more heat? This one or this one?
00:48:51Think hard. Heat energy is proportional to the product of voltage and current.
00:48:59I will ask each group, so make a prediction for this first.
00:49:19First with the parallel circuit.
00:49:22What should we do?
00:49:23I don't know either.
00:49:25You have to listen carefully.
00:49:27In that parallel circuit-
00:49:29The big resistance and the small resistance-
00:49:32Which one produces more heat?
00:49:34Then, I will call your name next, Yamase-kun.
00:49:37The small one, isn't it?
00:49:47Then stop. Class will be over soon, so I will ask you now.
00:49:51This one. Is there any group who has thought about this? Which one is larger?
00:49:55Then, Yoshikawa-kun's group.
00:49:59You answered. Yoshikawa-kun.
00:50:03Which one produces more heat?
00:50:06The one which has smaller resistance.
00:50:07Yes, yes. Same answer.
00:50:10Then Matsui-kun.
00:50:11One with the smaller resistance.
00:50:12One with the smaller resistance. How about the other group?
00:50:17Then Yoshikawa-kun, why does this one produce more heat?
00:50:24Huh? Then Matsui-kun. Why does this one produce more heat? Huh? Oh, this gesture indicates that the girls thought this out. Then I'll ask the girls. Then Kimo-san.
00:50:38Because the smaller the resistance is, the more current flows.
00:50:41The more current flows, right?
00:50:45Okay? In a parallel circuit, voltage is... the same everywhere. If that is the case, the more current flows, the greater the heat that is generated, right?
00:50:59So this one produces more heat. Then how about the series circuit? We don't have time, so I will ask you. Who thinks this one produces more heat?
00:51:14Then who thinks this one produces more heat?
00:51:18Some people are undecided. Then I will ask you in the next class, but I will give you a hint.
00:51:24In a parallel circuit, the voltage was the same, but what was the same in a series circuit?
00:51:35Yes. The current is the same. Think about this question, this hint in your mind.
00:51:41What does this mean? Then we will finish. Matsui-kun.
00:51:46Stand up.
00:51:54Then clean up after we greet.
00:52:06Yoshi-kun, you have to clean up, too.
00:52:12Thank you very much.
00:52:28Yamase-kun, Yamase-kun, come here.
00:52:39Oh, wait a minute. Stay seated for a little bit. There will be a survey, so please sit.