WEBVTT FILE 1 00:00:00.000 --> 00:00:03.250 Measure. Analyze. Learn. 2 00:00:03.750 --> 00:00:05.500 This is the Magnetic Field Sensor. 3 00:00:05.500 --> 00:00:08.500 It is used in several of our different manuals. 4 00:00:08.500 --> 00:00:12.000 And, it shows up in physics, middle school. 5 00:00:12.000 --> 00:00:15.000 And, it's a useful device to have. 6 00:00:15.000 --> 00:00:21.000 The sensitive part of the detector is right down here at the tip. 7 00:00:21.000 --> 00:00:23.500 What it does is, it measure magnetic fields 8 00:00:23.500 --> 00:00:26.500 that come in perpendicular to this white tip. 9 00:00:26.500 --> 00:00:30.000 It's what we call a hall probe. 10 00:00:30.000 --> 00:00:34.000 So what you want to do is move this relative to a magnet, 11 00:00:34.000 --> 00:00:37.000 and you could measure maybe things about the strength 12 00:00:37.000 --> 00:00:40.750 of the magnetic field as a function of distance from the magnet. 13 00:00:40.750 --> 00:00:43.000 There is an nice lab where you use electromagnets, 14 00:00:43.000 --> 00:00:45.500 where you use an electromagnet vary the number 15 00:00:45.500 --> 00:00:51.000 of turns on a nail, and to be able to do that. 16 00:00:51.000 --> 00:00:54.250 This tip down here is also flexible. 17 00:00:54.250 --> 00:00:58.000 So, we can move it perpendicular to the original direction. 18 00:00:58.000 --> 00:01:00.000 There's some labs where you may want to do that. 19 00:01:00.000 --> 00:01:04.000 You have it set in one setting, and then you move it, 20 00:01:04.000 --> 00:01:07.000 and look what happens to the strength of the field when you 21 00:01:07.000 --> 00:01:10.000 change the orientation of the sensor. 22 00:01:11.750 --> 00:01:14.000 This is a multi-range sensor. 23 00:01:14.000 --> 00:01:16.250 And so, there is a sensitivity switch here. 24 00:01:16.250 --> 00:01:19.750 So, there is a high and low amplification setting. 25 00:01:19.750 --> 00:01:22.250 The high amplification is actually the smallest number. 26 00:01:22.250 --> 00:01:25.000 And so, if you are looking at a fairly weak magnet, 27 00:01:25.000 --> 00:01:27.500 you can use high amplification. 28 00:01:27.500 --> 00:01:29.750 And, if you have a strong magnet, 29 00:01:29.750 --> 00:01:31.750 you can move it to the lower amplification. 30 00:01:31.750 --> 00:01:36.500 So it's a twenty-fold difference in the amplification there. 31 00:01:36.500 --> 00:01:38.750 So now, we're ready to collect some data. 32 00:01:38.750 --> 00:01:40.000 And I have a magnet here. 33 00:01:40.000 --> 00:01:41.000 It's just an old speaker. 34 00:01:41.000 --> 00:01:43.250 And, I'm just going to make some measurements around it, 35 00:01:43.250 --> 00:01:46.000 just to give us a reading there. 36 00:01:46.000 --> 00:01:48.000 So, I'm going to plug it in. 37 00:01:48.000 --> 00:01:51.500 It's an analog sensor, so we plug it into the analog port there. 38 00:01:51.500 --> 00:01:53.500 I'm going to collect some data. 39 00:01:53.500 --> 00:01:57.000 And, what I'm going to do is move the magnetic field sensor 40 00:01:57.000 --> 00:02:00.000 closer to the magnet, and then move it away from the magnet. 41 00:02:00.000 --> 00:02:04.500 And, I'm interested in looking at this as a time graph. 42 00:02:04.500 --> 00:02:06.000 The default setting for the device 43 00:02:06.000 --> 00:02:09.500 is a 10 second time based collection. 44 00:02:09.500 --> 00:02:11.250 And, to begin collection, 45 00:02:11.250 --> 00:02:13.750 I am going to press the start button here. 46 00:02:13.750 --> 00:02:17.400 And, I move the sensor closer to the magnet; 47 00:02:17.400 --> 00:02:20.000 I move it away from the magnet. 48 00:02:21.250 --> 00:02:23.750 And then when the run is complete 49 00:02:23.750 --> 00:02:25.500 it is going to auto scale the graph. 50 00:02:25.500 --> 00:02:27.250 And, what we're looking at there is the strength 51 00:02:27.250 --> 00:02:30.750 of the magnetic field relative to its position. 52 00:02:30.750 --> 00:02:34.000 And so as I got closer, I ended up with 53 00:02:34.000 --> 00:02:37.000 a larger negative number, in this case. 54 00:02:37.000 --> 00:02:39.250 And, as I moved away it got smaller. 55 00:02:39.250 --> 00:02:42.000 So, again, this sensor is used across the curriculum. 56 00:02:42.000 --> 00:02:44.750 It's very good to have. 57 00:02:44.750 --> 00:02:46.750 It allows student to measure magnetic fields 58 00:02:46.750 --> 00:02:47.750 in a way they haven't done before. 59 00:02:47.750 --> 00:02:49.250 They've discussed north and south, 60 00:02:49.250 --> 00:02:52.000 but they haven't discussed the actual quantitative 61 00:02:52.000 --> 00:02:54.250 measurement of the magnetic field strength.