JP3 CHEMICAL REACTIONS
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.
| Time | Caption |
|---|---|
| 00:00:02 | Teacher, can I (inaudible)? |
| 00:00:06 | No, Yoshi-kun. Let's begin. |
| 00:00:06 | //[bell] |
| 00:00:11 | Masa-kun, please. |
| 00:00:12 | Stand up. |
| 00:00:17 | Straight. |
| 00:00:18 | Bow. |
| 00:00:21 | //Please pay attention. |
| 00:00:26 | Today, we ask Ms. Yasui to help us. Where is the white chalk? |
| 00:00:34 | Do you remember we did a survey the last time? Watch on the board. |
| 00:01:05 | Today everyone is very- |
| 00:01:05 | OQuiet. |
| 00:01:06 | Quiet. |
| 00:01:07 | OQuiet, aren't they? |
| 00:01:08 | Very quiet. I've only experienced such quietness 2,3 times. Then everyone please read today's theme. One, two. |
| 00:01:20 | That's what I asked you the last time, right?When I asked enamel wire-Miso soup- |
| 00:01:22 | Refill lead of a mechanical pencil, things like that, your answers were clearly divided unexpectedly with these three items. |
| 00:01:54 | I would like to confirm it again. |
| 00:01:58 | Enamel wire, miso soup, refill lead of a mechanical pencil. I will demonstrate an experiment now. |
| 00:02:03 | Will 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? |
| 00:02:09 | If you think all three will, then you can raise your hand three times. |
| 00:02:13 | Enamel wire. This. Enamel wire. |
| 00:02:19 | You must have made electromagnets in elementary school. It's the conducting wire which you wound at that time. |
| 00:02:26 | Then miso soup. Today, I will use one with red bean paste. Miso soup with read bean paste. |
| 00:02:27 | Can we eat it? |
| 00:02:28 | Yes. If there are leftovers, I will give it to Masa. |
| 00:02:32 | And some refill lead of a mechanical pencil. |
| 00:02:35 | Then I will ask you. Okay? Then who thinks that the enamel wire will generate heat? |
| 00:02:42 | One, 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. |
| 00:02:53 | Miso soup. Miso soup with read bean paste. |
| 00:02:54 | Yes. |
| 00:02:56 | Only with read bean paste? |
| 00:02:57 | One, two, three, four, five, six, seven. Okay. |
| 00:03:01 | That has a lot of sodium. |
| 00:03:03 | Then the lead of a mechanical pencil. |
| 00:03:05 | This is serious. |
| 00:03:06 | One, two, three, four, five, six, seven, eight, nine, 10, 11, 12. Okay. |
| 00:03:11 | Then. Can anyone tell that it is certain from your own experience? Anyone? |
| 00:03:17 | What? |
| 00:03:18 | From your own experience, since you have done it before. Can anyone tell for sure? |
| 00:03:23 | Haven't you done it before? |
| 00:03:24 | Oh, the lead of a mechanical pencil... //the lead of a mechanical pencil- |
| 00:03:27 | Yes, Matsui-kun. Yes. Please stand up and speak. |
| 00:03:31 | Look at the camera. |
| 00:03:32 | Oh, no. |
| 00:03:33 | What? What? |
| 00:03:35 | I don't know, but the teacher of shop class- |
| 00:03:39 | Stand and speak. |
| 00:03:40 | Uh? |
| 00:03:41 | Stand up and speak. |
| 00:03:42 | It conducts electric current. |
| 00:03:43 | The teacher of shop class said so. |
| 00:03:44 | Said so. |
| 00:03:45 | Said so. That's fine. You can sit down. |
| 00:03:48 | Then lead of a mechanical pencil. These 12 people may be right. Anything else? Do you have experience? |
| 00:03:52 | No. |
| 00:03:53 | No? Then should we experiment in order? Then first we'll do it with an enamel wire. |
| 00:03:57 | Since it is hard to see my operation, Ms. Yasui will project it on that TV. But come to the front as usual. Please. |
| 00:04:18 | Can people in the front squat down? |
| 00:04:23 | If you cannot see it, you can watch the monitor. Then a little bit- |
| 00:04:30 | Murai-kun, you are the assistant. Please hold this. |
| 00:04:36 | So everyone can see the thermometer. Can you see what the temperature is now? |
| 00:04:40 | It won't reach all the way. |
| 00:04:41 | Oh, it won't reach? |
| 00:04:43 | This one- |
| 00:04:44 | What is the temperature? |
| 00:04:46 | Eight. |
| 00:04:47 | Eight degrees, right? Right now it's eight degrees. Then now I will make an electric current flow through this. |
| 00:04:51 | Here, at the tip of the thermometer, I have wound the enamel wire. If it generates heat, the thermometer will indicate it. |
| 00:05:02 | Ouch, ouch. Ouch. |
| 00:05:07 | Watch this. Oh, it is disconnected. |
| 00:05:11 | Wait. Okay. Watch. It is increasing, right? |
| 00:05:15 | It is. |
| 00:05:16 | What is the temperature now? |
| 00:05:18 | Thirty-two. |
| 00:05:19 | Seventeen. |
| 00:05:21 | It was only eight degrees before, but it's already seventeen degrees. |
| 00:05:23 | It's already about 20. |
| 00:05:24 | It's still rising. Yes. It's almost 20. |
| 00:05:26 | It's rising more and more. |
| 00:05:27 | I am getting an electric shock. |
| 00:05:28 | I am not getting it at all. See? |
| 00:05:31 | It's already 25. Should I show it to you? Look at the monitor. |
| 00:05:36 | Where is it? |
| 00:05:38 | Teacher, where is it? |
| 00:05:41 | Can you see that it has increased? |
| 00:05:44 | Wow. |
| 00:05:45 | It's increasing more and more. |
| 00:05:46 | Did it increase? |
| 00:05:47 | It's increasing. |
| 00:05:48 | This means that? |
| 00:05:49 | It's increasing. |
| 00:05:50 | It's increasing. |
| 00:05:51 | It's increasing, right? |
| 00:05:52 | Why don't you do it putting this down? |
| 00:05:54 | It's already 30 degrees. |
| 00:05:56 | Next, next. |
| 00:05:57 | It increased so much. |
| 00:05:58 | It increased so much. It was eight degrees, so how many degrees did it increase? |
| 00:06:00 | Twenty-two. |
| 00:06:01 | Twenty-two. Very well. |
| 00:06:03 | That means that an enamel wire is fine. It generates heat. Then next let's do it with miso soup. Miso soup. |
| 00:06:11 | Do we do all of this? |
| 00:06:13 | Miso soup is here, here. |
| 00:06:16 | I don't like it somehow. |
| 00:06:17 | I don't like it. |
| 00:06:18 | This is a present far you, Matsui-kun. |
| 00:06:20 | Far you? |
| 00:06:21 | Far you? |
| 00:06:24 | She spoke incorrect English. |
| 00:06:25 | Her English is incorrect. |
| 00:06:27 | You spoke incorrect English. |
| 00:06:28 | It's okay. |
| 00:06:29 | OShe is a science teacher. |
| 00:06:30 | She spoke incorrect English. |
| 00:06:35 | Then we use this aluminum foil as an electric pole and put this in the beaker. |
| 00:06:41 | You can leave it here. |
| 00:06:44 | Teacher, aren't you going to give me the one which is in the bag? |
| 00:06:47 | This one, right? I will give it to you, Matsui, so don't worry. Okay? |
| 00:06:53 | I put another electric pole here. |
| 00:06:56 | (inaudible) |
| 00:06:59 | There is something in the miso soup. |
| 00:07:01 | Oh, that's true. |
| 00:07:02 | Seaweed is in there. |
| 00:07:05 | Don't worry about my cooking. |
| 00:07:12 | Right now... it's five degrees. Five degrees. Five degrees. |
| 00:07:19 | Now I will connect this to the power source. |
| 00:07:29 | Can you see? |
| 00:07:30 | Can you see the inside of the miso soup is moving as soon as the switch was turned on? |
| 00:07:38 | The temperature is rising. The temperature is rising. |
| 00:07:40 | It's rising, right? |
| 00:07:42 | It'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. |
| 00:07:45 | I will put it in the front. |
| 00:07:48 | Can you see? Imai-kun, is it on? |
| 00:07:51 | Huh? |
| 00:07:52 | Is it on? |
| 00:07:55 | Something is brewing. |
| 00:07:56 | Is steam generating? It's also bubbling. What is the temperature now? What is the temperature now? |
| 00:08:02 | Twenty. |
| 00:08:04 | Now 20 degrees. It was five but it went up 15 degrees. |
| 00:08:07 | Bubbles are oozing. |
| 00:08:09 | Are bubbles oozing? |
| 00:08:11 | Try to touch it. It's warm. |
| 00:08:13 | Hot. Not hot. It's warm. |
| 00:08:15 | It's warm, right? Touch it. |
| 00:08:19 | It's warm. |
| 00:08:22 | It doesn't taste good. |
| 00:08:23 | What is the temperature now? |
| 00:08:27 | Teacher, that's no good. |
| 00:08:28 | Forty degrees. |
| 00:08:29 | It's rapidly increasing. |
| 00:08:30 | It's stinks. |
| 00:08:31 | Is this about right to drink? |
| 00:08:34 | Fifty degrees. |
| 00:08:35 | Fifty degrees? Then, Masa-kun, it's perfect to drink now. |
| 00:08:40 | This means? |
| 00:08:43 | Oh. |
| 00:08:44 | Miso soup is also? |
| 00:08:45 | It's burnt. |
| 00:08:47 | This bubbles- |
| 00:08:48 | Okay. Then, next, at last, shall we do it with the lead of a mechanical pencil? |
| 00:08:54 | This got very hot. It will break. |
| 00:08:56 | It will break? Stop it. |
| 00:08:59 | Then next is the lead of a mechanical pencil. |
| 00:09:03 | Then 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. |
| 00:09:20 | After I set it here. |
| 00:09:27 | That's fine. The connection is not good. |
| 00:09:29 | Oh, it's burning. |
| 00:09:30 | Hot, hot, hot! |
| 00:09:34 | It's burnt out! It's burnt out! |
| 00:09:36 | Hot, hot! It's burnt out! |
| 00:09:38 | Did you see that it burnt? |
| 00:09:41 | What is that, teacher? |
| 00:09:42 | This is steel wool. Right now, it's about two volts. |
| 00:09:48 | Zoom up more. |
| 00:09:51 | Max. |
| 00:09:52 | Maximum. |
| 00:09:54 | It's already burning. Steel burns. That means that it generated heat. |
| 00:10:01 | Then, //at last, the mechanical pencil. |
| 00:10:04 | //In short, you just brought something which generate heat, right? |
| 00:10:05 | Of course. |
| 00:10:07 | I knew it. |
| 00:10:08 | There is something which generates heat here. |
| 00:10:17 | Then I will do it with the mechanical pencil. |
| 00:10:37 | Oh! Acid rain! |
| 00:10:39 | It started smoking. It started smoking, so wait for a while. |
| 00:10:49 | People in the front, be careful. It may jump. |
| 00:10:54 | I'm fine because I'm wearing glasses. |
| 00:10:57 | Then I will increase the voltage. Right now I am increasing the voltage. |
| 00:11:03 | Something is changing a little. |
| 00:11:06 | Oh, it became red! It became red! |
| 00:11:07 | Not a little bit. A lot. |
| 00:11:09 | If you touch it, you will burn yourself. |
| 00:11:11 | You won't burn yourself. |
| 00:11:13 | This means that the lead of mechanical pencils also? |
| 00:11:15 | Conducts heat. |
| 00:11:16 | Yes, it generates heat, right? |
| 00:11:18 | It conducts heat. |
| 00:11:20 | Rather, it means that it conducts electric current, and generates heat. |
| 00:11:24 | It's bent. |
| 00:11:27 | It got thinner. |
| 00:11:28 | When it conducts heat? |
| 00:11:29 | Can you use the lead? |
| 00:11:31 | It already got so thin. |
| 00:11:34 | Then go back to your seat. |
| 00:11:50 | Almost anything will generate heat when current flows through it. |
| 00:11:59 | That 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. |
| 00:12:07 | Because the electron flow bumps atoms of the material, when they bump with atoms, it generates heat. |
| 00:12:18 | So today, the amount of heat generated, we will measure through an experiment the amount of heat that is generated. |
| 00:12:25 | What is this heat related to? As I just showed you, first, we increased the voltage, right? |
| 00:12:35 | So, it is probably related to the voltage. And if you increase the voltage, logically, what flows a lot? |
| 00:12:45 | Current. |
| 00:12:46 | Current flows, right? |
| 00:12:47 | So today, we will investigate through an experiment how heat increases in relation to the value derived from voltage times current. |
| 00:13:01 | Then look at the OHP. |
| 00:13:04 | Ms. Yasui is giving you some worksheets like this now. |
| 00:13:11 | Today, you will confirm through an experiment that heat generated by electric current is related to the value of voltage times current. |
| 00:13:20 | I will explain to you how to do it. I think now you got the worksheet, but first set up the equipment like this figure. |
| 00:13:32 | It doesn't show in this figure, but I think it will be good if you prepared a stand like this. |
| 00:13:37 | Then I will explain to you how to set up. First, in order to measure the amount of heat- |
| 00:13:45 | Are 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. |
| 00:13:57 | And in order to measure the voltage and the current, take a voltmeter and a ammeter. |
| 00:14:02 | The 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? |
| 00:14:14 | So 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. |
| 00:14:26 | It 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. |
| 00:14:35 | And the water will get warmer by the convection current, stir once in a while and measure the temperature. And- |
| 00:14:43 | Ammeter is in series circuit, voltmeter is in a parallel circuit, the tip is sticking out, so connect the clips here. Two each. |
| 00:14:53 | And, please measure the temperature of the water before you start. |
| 00:14:58 | When you did the survey the last time, I found that you forgot how to calculate heat energy. |
| 00:15:03 | But 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. |
| 00:15:12 | So in order to calculate heat energy, the mass of water in this container multiplied by the increase in temperature. |
| 00:15:23 | In order for everyone to have the same amount of water, I have measured 100 grams and put in there today. Okay? |
| 00:15:30 | I have prepared 100 grams of water here which has been measured, so please take it from here. The thermometer is also in there. |
| 00:15:40 | And uh... each group read the value of the current with specified voltage. |
| 00:15:46 | And 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. |
| 00:15:58 | So please tell me when your group finishes setting up the equipment and are ready. When everyone is ready, we will measure five minutes. |
| 00:16:04 | Now, since every group will measure with a specified voltage, can you please write the voltage here? Here. |
| 00:16:16 | First 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. |
| 00:16:26 | Then, this row, write three volts and six volts in here. |
| 00:16:28 | What? |
| 00:16:29 | This row, write three volts and six volts. |
| 00:16:32 | Then 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. |
| 00:16:43 | Do we adjust to seven volts? |
| 00:16:44 | Yes. Please adjust seven volts with the voltmeter precisely. |
| 00:16:49 | Five volts and? |
| 00:16:51 | Five volts and seven volts. |
| 00:16:57 | Then, I will explain to you again. Face this way. |
| 00:17:01 | For example, these groups have three volts and six volts here, right? |
| 00:17:06 | During the experiment, this group will give three volts of voltage at the same time as everyone and measure five minutes. |
| 00:17:12 | Read the ammeter, and see how many amperes it is. And after five minutes, write how much temperature increase there was. |
| 00:17:21 | And 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. |
| 00:17:34 | And as for heat energy, you calculate mass of the water times temperature increase. Okay? |
| 00:17:41 | When you are done, you will have an OHP sheet which Ms. Yasui will give to you. OHP sheets look like this. |
| 00:17:49 | This graph is to record the relationship between the value of voltage times current and the number for increased temperature of the water. |
| 00:17:56 | And as for this one, please record the relation between the value of voltage times current and the amount of heat generated. |
| 00:18:02 | And when you record, just mark dots like this one. This group will have values for three volts and six volts, right? |
| 00:18:11 | This group will have values for four volts and eight volts, right? This group will have values for five volts and seven volts, right? |
| 00:18:17 | When 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, |
| 00:18:28 | Will 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? |
| 00:18:37 | We will come over when you are not sure. What you have to prepare is the electric heating wire, here. Voltmeter and ammeter. |
| 00:18:45 | Take the power source from there as usual. And each group take two cups, okay? We measure twice, okay? For three volts and six volts. |
| 00:18:56 | So prepare those although we use one of them first. Do you have any questions? |
| 00:19:02 | No. |
| 00:19:03 | You don't? Then each group, get ready. |
| 00:19:10 | Stands are over there. |
| 00:19:27 | Sorry, sorry. |
| 00:19:30 | I have to put the thermometer for the miso-soup as well. |
| 00:19:42 | You need two cups. One for five volts and another for seven volts. |
| 00:19:44 | Oh. |
| 00:19:45 | You must change. |
| 00:19:48 | You told me I have to do well. |
| 00:19:50 | I told you to do well during the experiment. |
| 00:19:55 | Isn't' this (inaudible)? Don't touch it. |
| 00:20:00 | Teacher, the thermometer too? |
| 00:20:01 | The thermometer too. |
| 00:20:03 | Do I need (inaudible)? |
| 00:20:05 | Should I take this? |
| 00:20:06 | Don't drop it. |
| 00:20:09 | O(inaudible). |
| 00:20:15 | Wasn't there enough? |
| 00:20:19 | OHow many were there? |
| 00:20:20 | There must have been eight. |
| 00:20:26 | Should I do it with this group? OHP needs to be marked clearly so please write with this. Then first set up. |
| 00:20:37 | When you are done setting up, everyone starts together. |
| 00:20:44 | Isn't it better to hang it in this side? It is unstable. |
| 00:20:55 | Hang it so that it will be in the water. |
| 00:21:01 | Teacher, this? |
| 00:21:02 | About five minutes. |
| 00:21:03 | The spring-like thing. |
| 00:21:04 | Oh, electric heating wire? |
| 00:21:06 | Huh? There should be eight. Sorry, did anyone take two heating wires? There should have been eight of these. |
| 00:21:16 | Oh, you took too many, okay, okay. |
| 00:21:18 | Here they are. |
| 00:21:29 | Put the thermometer in the cup and set it up. |
| 00:21:32 | (inaudible) |
| 00:21:33 | No, from the side. |
| 00:21:34 | Yes, yes. You measure the temperature of the water first. This is unstable, so from this side. |
| 00:21:46 | Since we want to measure the temperature of the water first, please hurry up and set up the water. |
| 00:21:56 | After hanging it, support it with your hand. |
| 00:22:04 | Kawai-san... Here, it's your turn, Masago. |
| 00:22:07 | You have to hold this one like this. |
| 00:22:09 | Yes. That's why you should hang the thermometer. |
| 00:22:15 | Masago-kun, you turn that so that you can hang the string. |
| 00:22:18 | Oh. |
| 00:22:31 | Why don't you put it here? |
| 00:22:58 | And set it in a series circuit. Which one is positive? |
| 00:23:04 | This one, right? Yes, yes. |
| 00:23:10 | This one is negative, right? And this one is positive. |
| 00:23:14 | This one, this one. |
| 00:23:21 | This one may fall off. |
| 00:23:22 | That's fine. |
| 00:23:24 | Yes. Then please wait if you finished setting up. |
| 00:23:27 | If you are behind in setting up, I will help you. |
| 00:23:31 | Oh! |
| 00:23:33 | Should I help you? Are you finished setting up? |
| 00:23:35 | Is this okay? (inaudible) |
| 00:23:38 | Oh... 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. |
| 00:23:49 | Are you done? |
| 00:23:52 | Set the ammeter in a series circuit. |
| 00:23:58 | Plus five amperes, right? And this one? This one is positive, so connect the negative here. And put this one here. |
| 00:24:13 | Are you done? |
| 00:24:22 | Why don't you do it from the side? Like this. This clip is dirty so it may be better to change it. |
| 00:24:33 | This is a clean one. |
| 00:24:35 | Here you are. Please someone hold it. Here you are. |
| 00:24:42 | Then record the original water temperature when you are done setting up. |
| 00:24:46 | Record the original water temperature. |
| 00:24:53 | Are you done setting up? Hurry up and set up, since everyone is waiting for you. |
| 00:24:59 | How many volts should we have first? |
| 00:25:06 | Five amperes. |
| 00:25:07 | You have to connect one to the ammeter. Is this positive? Then put this to the positive. |
| 00:25:21 | And this? |
| 00:25:27 | Should we put this to here then? |
| 00:25:30 | Mei, the ammeter is not connected. |
| 00:25:36 | This 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. |
| 00:25:48 | (inaudible) |
| 00:25:51 | Are you done? Yamase-kun's group, are you done? Okay? |
| 00:25:55 | Then we will start five minutes from now. Set the first voltage with the voltmeter. |
| 00:26:07 | Then we will start. |
| 00:26:10 | First we do it with four volts. |
| 00:26:11 | First, set it to your voltage. |
| 00:26:13 | If 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. |
| 00:26:18 | If you do it with five volts and seven volts, start with five volts. |
| 00:26:22 | You adjust with the voltmeter, you know? |
| 00:26:23 | It's this one, right? |
| 00:26:24 | Yes. Read with the voltmeter. Not that one. Read it with the voltmeter. Anyone that doesn't understand? |
| 00:26:39 | Ms. Yasui, are we ready? |
| 00:26:44 | Ms. Yasui, are we ready? |
| 00:26:49 | Ready? Then we will do it for five minutes. Okay? |
| 00:26:57 | Yes. Are we ready? Ready? Then ready, go! |
| 00:27:04 | Then, put in the water. |
| 00:27:08 | OWait, wait. |
| 00:27:10 | We cannot wait. |
| 00:27:12 | Stir sometimes. Stir sometimes, please. |
| 00:27:21 | Read the voltmeter now. |
| 00:27:25 | It was hot. |
| 00:27:27 | You are doing it with four volts, right? Does it say four volts? |
| 00:27:29 | Yes. |
| 00:27:30 | Yes? |
| 00:27:31 | Huh? |
| 00:27:32 | You have to adjust it to four volts. |
| 00:27:33 | Huh? We adjusted it before, didn't we? |
| 00:27:34 | Did something move? |
| 00:27:37 | Huh? |
| 00:27:38 | The current is not flowing. |
| 00:27:39 | Is there some part which is disconnected? |
| 00:27:41 | Really? |
| 00:27:44 | Let's turn it off once. |
| 00:27:46 | Was it okay before? |
| 00:27:48 | Yes, it was. |
| 00:27:50 | Did it short circuit? |
| 00:28:02 | Are the positive and the negative okay? |
| 00:28:05 | This is positive, so this is positive. This one is negative. This is correct. Then should we do it again? |
| 00:28:13 | That side- |
| 00:28:14 | It's not increasing. |
| 00:28:15 | It's not increasing, is it? |
| 00:28:16 | Why? |
| 00:28:24 | Why is it not increasing? |
| 00:28:31 | A little bit. |
| 00:28:33 | Can I disconnect it once? I will (inaudible). |
| 00:28:41 | Your group was supposed to do it with four volts and eight volts, right? Then you can start next with eight volts. |
| 00:28:48 | It starts from positive and- |
| 00:28:54 | It starts from negative and- |
| 00:28:57 | This one, right? It goes from positive and here, right? |
| 00:29:00 | And put the positive of the voltmeter here. |
| 00:29:08 | Teacher, it is not good if this and this are touching, is it? |
| 00:29:11 | Yes, it's better if it's not touching. |
| 00:29:13 | They are touching. |
| 00:29:14 | Then let's try now. |
| 00:29:17 | It's not going up yet? |
| 00:29:18 | It's not going up. |
| 00:29:19 | Why is that? |
| 00:29:20 | The voltmeter is working. How about the ammeter? The ammeter is not working either. |
| 00:29:34 | Nothing is wrong with the power source. |
| 00:29:40 | Did it touch the heating wire by mistake? |
| 00:29:51 | It went up. |
| 00:29:52 | It 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. |
| 00:30:04 | I was worried. |
| 00:30:05 | Next one, right? |
| 00:30:06 | Yes, you can do the next one. |
| 00:30:09 | You can get the data from the neighboring group. |
| 00:30:14 | Did it work? |
| 00:30:15 | OVoltmeter was working till just now. |
| 00:30:18 | We have problems. |
| 00:30:19 | Mr. Cameraman, we have problems. |
| 00:30:25 | Did you connect correctly? |
| 00:30:30 | Oh, it went up. |
| 00:30:32 | It went up fine. |
| 00:30:34 | OIt went up? Oh it went back? |
| 00:30:37 | Move this one too. |
| 00:30:38 | It's too much. |
| 00:30:39 | How many volts are you suppose to have? |
| 00:30:40 | Five volts. |
| 00:30:41 | Not yet, not yet. |
| 00:30:43 | Little less, little less. Stop. |
| 00:30:44 | Did it work? |
| 00:30:45 | Yes, it did work. |
| 00:30:46 | Then you start with the next seven volts also. |
| 00:30:49 | Huh? |
| 00:30:50 | Since these five minutes have already started. Okay? |
| 00:30:53 | OTeacher, was something wrong with that part? |
| 00:30:54 | This part was bent, so I think the connection inside was not good. |
| 00:30:55 | OOh, I see. |
| 00:30:59 | Don't bend here. If you bend this, Yamase- |
| 00:31:02 | We didn't do it. |
| 00:31:03 | Really? |
| 00:31:04 | Why me? |
| 00:31:05 | Yes, yes. |
| 00:31:08 | Then, next you can measure the seven volts well, right? Then get the data from your neighboring group. |
| 00:31:19 | Stir it sometimes. |
| 00:31:25 | Thirty seconds more. |
| 00:31:29 | Thirty seconds more. |
| 00:31:34 | That's fine. It's three volts, right? Then zero point six amperes, right? |
| 00:31:39 | Calculate here now. It's three volts times zero point six amperes, so how much? |
| 00:31:46 | You can calculate in your head. |
| 00:31:49 | One point eight. |
| 00:31:50 | Yes, one point eight... volt-amperes. |
| 00:31:57 | Then... write volt-amperes. |
| 00:32:01 | [timer] |
| 00:32:03 | Now, measure the temperature. How many degrees did it increase from the original temperature? |
| 00:32:07 | Can you take turns? |
| 00:32:13 | You guys... You (inaudible). |
| 00:32:15 | Thirty-seven. |
| 00:32:17 | Thirty-seven? |
| 00:32:18 | Thirty-seven. |
| 00:32:22 | Then please write how many degrees it has increased. |
| 00:32:27 | Then we will do the next one. Change the cup. |
| 00:32:31 | Thirty degrees Celsius. Then what about this one? |
| 00:32:36 | Change the cup. We will do it for the next five minutes. |
| 00:32:39 | Is 30 the number that increased? |
| 00:32:40 | It increased from seven to 37, right? |
| 00:32:45 | Then your group is doing it with six volts, right? Six volts next, right? |
| 00:32:53 | While the thermometer settles down, you can calculate heat energy. In order to make the thermometer settle down, calculate heat energy. |
| 00:33:00 | I forgot how to calculate heat energy. |
| 00:33:04 | OTurn off the power source. |
| 00:33:10 | Next you will increase the voltage, so I think it is better to increase the ampere too. |
| 00:33:17 | Wait until the water temperature is settled. |
| 00:33:19 | Water mass was 100 grams. |
| 00:33:20 | One hundred grams? |
| 00:33:21 | Yes. |
| 00:33:23 | One hundred times the number of temperature increase- |
| 00:33:24 | Wait a minute. It wasn't 37. It was 47. |
| 00:33:26 | Your group only had a little increase? |
| 00:33:28 | Yes. |
| 00:33:29 | Well, that's fine. That is your result. How many amperes was the current? |
| 00:33:32 | Three. |
| 00:33:33 | Huh? |
| 00:33:34 | How many amperes was the current at that time? |
| 00:33:37 | It increased around here first. Was it around here? One hundred, around here? |
| 00:33:44 | How many? |
| 00:33:46 | Uh... zero point five. |
| 00:33:50 | Was it zero point five? Then write here zero point five amperes. |
| 00:33:57 | Then, this was voltage times current, so three times zero point five. |
| 00:34:04 | Three times zero point five. |
| 00:34:14 | Zero point five is half. So what is half of three volts? |
| 00:34:18 | One point five. |
| 00:34:19 | One point five, right? One point five. |
| 00:34:24 | Read this, "volt-ampere." |
| 00:34:27 | Do I write it like this? |
| 00:34:29 | And write a dot here since this is multiplication. |
| 00:34:32 | Then 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- |
| 00:34:40 | How many calories? One hundred times two equals? |
| 00:34:44 | Two hundred. |
| 00:34:44 | Yes, 200 calories. Do it like that. |
| 00:34:52 | How do you read current ampere? |
| 00:34:54 | You 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? |
| 00:35:00 | Yes. |
| 00:35:01 | Is this 15? |
| 00:35:03 | That's voltmeter. How about the ammeter? |
| 00:35:05 | Huh? //Isn't this ampere? |
| 00:35:07 | //This was twelve point five amperes? |
| 00:35:09 | It was three. |
| 00:35:10 | Huh? |
| 00:35:11 | Huh? |
| 00:35:12 | This was, right? You wrote twelve point five. Was the current really //twelve point five? |
| 00:35:15 | //No, it was three. |
| 00:35:17 | Three. |
| 00:35:18 | It was wrong, right? |
| 00:35:19 | No, it wasn't. |
| 00:35:20 | This is a ammeter, so- |
| 00:35:21 | Ouch. |
| 00:35:22 | Ouch. How much? |
| 00:35:24 | Ouch. |
| 00:35:25 | It can only measure up to five amperes, so it cannot be possible to measure twelve point five amperes. |
| 00:35:28 | What we measured was three and six. |
| 00:35:30 | That's voltage. I'm asking about the electric current. Was the current flow twelve point five amperes? |
| 00:35:36 | Huh? |
| 00:35:37 | The ammeter. //Did twelve point five amperes flow? |
| 00:35:39 | //She is asking how much current flowed. |
| 00:35:44 | We adjusted this before, didn't we? |
| 00:35:45 | Only three amperes flowed. |
| 00:35:47 | No, 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. |
| 00:35:52 | What? |
| 00:35:54 | [laughter] |
| 00:35:56 | What did you adjust to three volts then? This is a ammeter. |
| 00:36:04 | This is the voltmeter. |
| 00:36:07 | Huh? |
| 00:36:13 | But nobody noticed. |
| 00:36:14 | Nobody noticed? |
| 00:36:17 | Teacher (inaudible), didn't she? |
| 00:36:19 | No, I said adjust it with this one. |
| 00:36:22 | Did she say that? |
| 00:36:23 | This data... I thought the temperature went up too much. |
| 00:36:28 | Saki-chan. |
| 00:36:29 | Since you cannot use this data, start with six volts. |
| 00:36:31 | Yes. |
| 00:36:33 | Oh, no. |
| 00:36:34 | We, we were holding this all the time. We were holding it. And at the certain point- |
| 00:36:39 | This is a ammeter. |
| 00:36:41 | Do we have to adjust with this one? |
| 00:36:42 | Unless it is voltmeter, you cannot measure voltage. |
| 00:36:44 | (inaudible) |
| 00:36:47 | Well then, we will start the next experiment. |
| 00:36:52 | Then please read the thermometer. |
| 00:36:57 | Then we will start. Okay? Measure voltage with voltmeter. You cannot measure it with a ammeter. We will start. |
| 00:37:11 | We will start. Ready. |
| 00:37:13 | Teacher, teacher, wait a second. |
| 00:37:15 | Should I wait a little bit? |
| 00:37:16 | Four more minutes. |
| 00:37:22 | This is wet. |
| 00:37:23 | What are you doing? |
| 00:37:24 | What are you doing? |
| 00:37:25 | (inaudible) |
| 00:37:26 | Hold it with your hand, don't be lazy. You are making everyone wait. |
| 00:37:32 | Hurry, hurry. Put it down, put it down. |
| 00:37:33 | Ready? |
| 00:37:36 | The group over there. Did you read the thermometer? |
| 00:37:39 | Of course. |
| 00:37:40 | Yoshikawa-kun, did you read the thermometer? |
| 00:37:42 | We are reading it right now. |
| 00:37:44 | Can I raise this to here? |
| 00:37:46 | That's fine. Don't worry about it. |
| 00:37:52 | Oh, no. That group is- |
| 00:37:54 | I will start. Ready? Go. |
| 00:37:56 | Seriously? |
| 00:37:57 | Ready, go. |
| 00:37:58 | Voltage should be six, right? |
| 00:38:00 | Six, six, six. |
| 00:38:05 | This should be eight voltage this time, right? |
| 00:38:07 | Yes. |
| 00:38:08 | Yes. |
| 00:38:09 | Bubble is oozing. |
| 00:38:10 | That's fine. |
| 00:38:12 | Is it okay? |
| 00:38:13 | Stir it once in a while. |
| 00:38:22 | Don't make a mistake this time. Oh. Oh. |
| 00:38:26 | This one is one point five, right? |
| 00:38:28 | Only five amperes, right? Yes. |
| 00:38:29 | Five amperes? |
| 00:38:30 | Five amperes? |
| 00:38:31 | Oh. |
| 00:38:32 | This means it is one point five volts. |
| 00:38:34 | Why did you mix up a voltmeter and a ammeter again? We did it so many times... Oh well. |
| 00:38:39 | Because the color is blue and green. |
| 00:38:41 | Then multiply this current and this voltage. |
| 00:38:44 | Five times six equals 30- |
| 00:38:46 | Yes. |
| 00:38:48 | Sixteen, 18- |
| 00:38:50 | Nine. |
| 00:38:51 | [laughter] |
| 00:38:53 | Nine, right? |
| 00:38:56 | (inaudible) |
| 00:38:57 | This time do it well, okay? |
| 00:39:00 | Don't worry, since that group made mistakes, your group's two degrees increase is just about right. |
| 00:39:05 | (inaudible) |
| 00:39:08 | Sometimes people make mistakes. |
| 00:39:10 | But I think this is unusual. |
| 00:39:20 | Then while you are waiting for five minutes, put dots for the previous data in the graph on an OHP sheet. |
| 00:39:32 | Should I tell you how to use this? |
| 00:39:37 | In 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? |
| 00:39:47 | Next, 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. |
| 00:39:55 | The next one is the same way. Just put a dot. Okay? |
| 00:39:58 | Just dots? |
| 00:39:59 | Yes, just putting dots is fine. |
| 00:40:01 | Then watch it carefully so that you won't make a mistake next time. The next data is with nine, right? |
| 00:40:05 | Since you will have only one dot, this is voltage multiplied by current, you will see how many degrees it increased after five minutes. |
| 00:40:13 | At 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. |
| 00:40:23 | How do we calculate heat energy? |
| 00:40:24 | The amount of heat energy is mass of water multiplied by temperature increase. |
| 00:40:27 | Teacher, when I calculated it with the previous data, it became 3,000. |
| 00:40:30 | Three thousand. |
| 00:40:31 | Is the mass of water 100? |
| 00:40:32 | Yes, today it was 100 grams. |
| 00:40:35 | The number of increased temperature is 30- |
| 00:40:37 | But your group applied a fairly high voltage because in order to ten? three, three amperes. |
| 00:40:47 | Teacher. |
| 00:40:48 | Yes. |
| 00:40:50 | Oh, this one, right? It became one point five, right? This one goes two, four, six; so one point five is around here, right? |
| 00:40:56 | And then the number of increased temperature is two, right? Around here. So put a dot around here. |
| 00:41:03 | Next is the same way. When it is one point five volt-ampere, it is 200 calories, right? |
| 00:41:07 | Since this side is for heat energy, so when it is one point five, circle at 200 calories. Okay? |
| 00:41:18 | How is it? You have only one datum. Then, first multiply current and voltage, first. Eight times one point three. |
| 00:41:29 | How much is it, Hirai-kun. |
| 00:41:31 | Ten point four. |
| 00:41:32 | Ten point four. He said ten point four. |
| 00:41:34 | Ten point four. |
| 00:41:37 | Then, you draw the number of the temperature increase after five minutes, right? And for calculating heat energy- |
| 00:41:44 | Since the heat that was given by the electric wire is the same as the heat that was received by the water- |
| 00:41:47 | The mass of the water is 100, right? And multiply the number of the temperature increase and get the amount of heat. Okay? |
| 00:41:55 | And when you write it in here, it is ten point four. This is 10 and 12, right? Find where ten point four is. |
| 00:42:02 | And put the dot in here at the temperature increase. |
| 00:42:06 | Imai-kun has suspicious eyes. |
| 00:42:08 | In 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. |
| 00:42:22 | Were you explained how to draw the graph? Okay? |
| 00:42:27 | This is big. |
| 00:42:29 | That's fine. Big is fine. |
| 00:42:32 | Twenty more seconds. |
| 00:42:35 | Get ready to read the thermometer. |
| 00:42:37 | Well, now it's 16 degrees// |
| 00:42:39 | //(inaudible) get ready to write// |
| 00:42:40 | //this is 16. |
| 00:42:41 | Did you put dots? |
| 00:42:45 | Where? Oh, I cannot see it. Draw it clearly. |
| 00:42:48 | Teacher. |
| 00:42:48 | Yes. |
| 00:42:50 | This one? You got six point five, right? It's six point five, so is it about here? |
| 00:42:55 | [timer] |
| 00:42:57 | Then read the next temperature. |
| 00:42:58 | It's over. |
| 00:43:01 | It increased four degrees, right? So it's four, yes, yes. |
| 00:43:08 | We are done. |
| 00:43:10 | How many degrees have increased? |
| 00:43:11 | You know, right? |
| 00:43:12 | That's why it's one point six. |
| 00:43:14 | It's 14, I heard. |
| 00:43:17 | Fourteen. Thirteen. |
| 00:43:21 | Did it increase 11 degrees? |
| 00:43:24 | This one is the number of increase, so you have to write four for this. |
| 00:43:26 | Oh, I see. |
| 00:43:31 | Yes, yes. And this... you draw a circle, but this is for calorie. |
| 00:43:35 | Oh, calorie. |
| 00:43:44 | Then, when you draw on the sheet, bring it to me. |
| 00:43:50 | It's ten point five. Is it around here? |
| 00:43:53 | Make sure to turn off the power source. |
| 00:44:00 | When you are done with the sheet, bring it to me. |
| 00:44:04 | ODraw it with this pen. |
| 00:44:07 | Where? Here? |
| 00:44:10 | ODraw it bigger. |
| 00:44:21 | Then next. Next is? |
| 00:44:24 | The size is different. |
| 00:44:27 | When you finished the sheet, bring it to me. |
| 00:44:30 | Should I make it thicker? Like fat people. It is clearer in this way. These are so reserved. Then I will take this. Thank you. |
| 00:44:43 | When you are done, please bring it to me. |
| 00:44:54 | Are you done? Oh this was yours. |
| 00:44:57 | Bring the sheet quickly please. |
| 00:45:02 | The group who turned in the sheet, please look at the OHP. |
| 00:45:13 | Is this okay just like this? |
| 00:45:14 | That's fine. We will stick them. |
| 00:45:34 | Did everyone turn it in? |
| 00:45:36 | OSix point five and 400 degrees. |
| 00:45:42 | The group who turned it in, please watch this. |
| 00:45:45 | OAround here. |
| 00:45:47 | Thank you for bringing it to me. |
| 00:45:48 | OThen... eleven point two and eight degrees. Eleven point two is eight degrees. |
| 00:45:54 | Eleven point two. |
| 00:45:56 | OThen eight degrees. |
| 00:45:59 | One more group? |
| 00:46:08 | Kaji-kun, please take it. |
| 00:46:14 | Thank you. |
| 00:46:22 | Then, let's take a look. |
| 00:46:27 | I stuck all of them together. Then the result of your measurement became like this. So should I draw a line? |
| 00:46:38 | May I borrow your ruler? |
| 00:46:43 | Thanks. |
| 00:46:45 | This... when the voltage and the current are both zero, there is neither temperature nor heat energy. Here. Origin, okay? |
| 00:46:56 | Then I will draw a line so that it is close to all the dots. |
| 00:47:09 | Oh! Amazing! They are exactly on the line! |
| 00:47:11 | Yes, some are exactly on the line. |
| 00:47:12 | See? |
| 00:47:13 | That means- |
| 00:47:17 | What can we say from this? |
| 00:47:19 | This is amazing. |
| 00:47:24 | Voltage times current equals... what kind of relationship is there in relation to temperature increase and heat energy? |
| 00:47:41 | Proportion. |
| 00:47:42 | Proportion. |
| 00:47:43 | Proportion. |
| 00:47:47 | What is it? One more time? |
| 00:47:49 | Proportion. |
| 00:47:50 | It has a proportional relationship, right? |
| 00:47:57 | Okay? |
| 00:47:59 | We found that heat energy is proportional to the product of voltage and current. |
| 00:48:06 | Then using this result, please try to solve this question. |
| 00:48:11 | Okay? Heat energy is proportional to the product of voltage and current. |
| 00:48:19 | Then, this question. |
| 00:48:24 | This 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. |
| 00:48:39 | Then 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? |
| 00:48:51 | Think hard. Heat energy is proportional to the product of voltage and current. |
| 00:48:59 | I will ask each group, so make a prediction for this first. |
| 00:49:19 | First with the parallel circuit. |
| 00:49:22 | What should we do? |
| 00:49:23 | I don't know either. |
| 00:49:25 | You have to listen carefully. |
| 00:49:27 | In that parallel circuit- |
| 00:49:28 | Yes. |
| 00:49:29 | The big resistance and the small resistance- |
| 00:49:31 | Yes. |
| 00:49:32 | Which one produces more heat? |
| 00:49:33 | Yes. |
| 00:49:34 | Then, I will call your name next, Yamase-kun. |
| 00:49:37 | The small one, isn't it? |
| 00:49:47 | Then stop. Class will be over soon, so I will ask you now. |
| 00:49:51 | This one. Is there any group who has thought about this? Which one is larger? |
| 00:49:54 | Yes. |
| 00:49:55 | Then, Yoshikawa-kun's group. |
| 00:49:59 | You answered. Yoshikawa-kun. |
| 00:50:03 | Which one produces more heat? |
| 00:50:06 | The one which has smaller resistance. |
| 00:50:07 | Yes, yes. Same answer. |
| 00:50:09 | [bell] |
| 00:50:10 | Then Matsui-kun. |
| 00:50:11 | One with the smaller resistance. |
| 00:50:12 | One with the smaller resistance. How about the other group? |
| 00:50:17 | Then Yoshikawa-kun, why does this one produce more heat? |
| 00:50:24 | Huh? 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. |
| 00:50:38 | Because the smaller the resistance is, the more current flows. |
| 00:50:41 | The more current flows, right? |
| 00:50:45 | Okay? 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? |
| 00:50:59 | So 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? |
| 00:51:14 | Then who thinks this one produces more heat? |
| 00:51:18 | Some people are undecided. Then I will ask you in the next class, but I will give you a hint. |
| 00:51:24 | In a parallel circuit, the voltage was the same, but what was the same in a series circuit? |
| 00:51:34 | Current. |
| 00:51:35 | Yes. The current is the same. Think about this question, this hint in your mind. |
| 00:51:41 | What does this mean? Then we will finish. Matsui-kun. |
| 00:51:46 | Stand up. |
| 00:51:54 | Then clean up after we greet. |
| 00:52:02 | Straight. |
| 00:52:06 | Yoshi-kun, you have to clean up, too. |
| 00:52:10 | Bow. |
| 00:52:12 | Thank you very much. |
| 00:52:28 | Yamase-kun, Yamase-kun, come here. |
| 00:52:39 | Oh, wait a minute. Stay seated for a little bit. There will be a survey, so please sit. |