0:00:07.464,0:00:10.047 (upbeat music) 0:00:44.370,0:00:45.527 - [Narrator] Chemistry lab is different 0:00:45.527,0:00:47.430 from most other courses. 0:00:47.430,0:00:49.975 Here you gain new[br]knowledge by doing things, 0:00:49.975,0:00:51.903 not just reading about them. 0:00:53.700,0:00:55.950 You'll spend much of your[br]time in chemistry lab 0:00:55.950,0:00:59.460 working with equipment and[br]techniques that are new to you. 0:00:59.460,0:01:01.620 They can be dangerous if you don't adhere 0:01:01.620,0:01:03.753 to strict safety procedures. 0:01:04.770,0:01:07.350 But if you start with safety[br]by following the rules, 0:01:07.350,0:01:10.710 paying attention and using common sense, 0:01:10.710,0:01:12.870 you can work with confidence[br]that you'll be safe 0:01:12.870,0:01:14.700 in the chemistry laboratory. 0:01:14.700,0:01:16.893 And you can have fun at the same time. 0:01:32.640,0:01:34.993 Handling chemicals safely[br]means following rules 0:01:34.993,0:01:37.898 designed to keep them from[br]contacting your skin and eyes 0:01:37.898,0:01:40.800 or someone else's. 0:01:40.800,0:01:44.940 One important safety rule is[br]always use small containers 0:01:44.940,0:01:46.803 that you can control easily. 0:01:47.970,0:01:50.940 Ignoring this rule can cause accidents. 0:01:50.940,0:01:54.540 If you have an accident,[br]always inform your teacher. 0:01:54.540,0:01:57.453 Pouring from small[br]containers is far safer. 0:01:59.490,0:02:03.210 Accidents can also happen[br]when mixing chemicals 0:02:03.210,0:02:04.290 - Is this okay? 0:02:04.290,0:02:05.160 - Looks fine. 0:02:05.160,0:02:06.690 You can go ahead and get started. 0:02:06.690,0:02:08.220 - Okay, thank you 0:02:08.220,0:02:10.500 - [Narrator] To be safe only mix chemicals 0:02:10.500,0:02:12.720 when your teacher says to. 0:02:12.720,0:02:14.790 Read the instructions for the experiment 0:02:14.790,0:02:16.290 all the way through first 0:02:16.290,0:02:18.270 before doing anything. 0:02:18.270,0:02:19.920 Read and reread labels 0:02:19.920,0:02:23.340 before use to make sure you've[br]got the right chemicals. 0:02:23.340,0:02:26.223 Note, the concentration[br]and the hazard warning. 0:02:27.480,0:02:29.760 Accidents can happen[br]when the wrong chemicals 0:02:29.760,0:02:32.310 are mixed together or[br]when the right chemicals 0:02:32.310,0:02:34.533 are mixed together in the wrong way. 0:02:35.550,0:02:38.790 Make sure to follow your[br]instructions exactly. 0:02:38.790,0:02:40.380 For example, suppose you have 0:02:40.380,0:02:43.860 to dilute concentrated[br]sulfuric acid with water. 0:02:43.860,0:02:45.720 You might think you[br]could mix them together 0:02:45.720,0:02:47.400 anyway you wish, 0:02:47.400,0:02:48.810 but there's an important rule 0:02:48.810,0:02:52.650 for diluting concentrated[br]sulfuric or phosphoric acid 0:02:52.650,0:02:55.110 that should always be followed. 0:02:55.110,0:02:58.680 Add the acid to the[br]water, never the reverse. 0:02:58.680,0:03:02.403 Remember it by the initials AA add acid. 0:03:03.420,0:03:06.153 Watch what happens when[br]you don't follow this rule. 0:03:12.210,0:03:14.430 This is water added to acid. 0:03:14.430,0:03:17.883 The acid boils, and it can[br]splash out of the beaker. 0:03:26.160,0:03:28.710 When acid and water are mixed correctly 0:03:28.710,0:03:30.600 there's less danger. 0:03:30.600,0:03:32.880 Acid is poured from a graduated cylinder 0:03:32.880,0:03:36.003 or beaker down a stirring[br]rod into the water. 0:03:39.960,0:03:41.580 Whenever you work with chemicals 0:03:41.580,0:03:43.680 there's a chance of spills. 0:03:43.680,0:03:46.773 A work tray under your setup[br]will help contain them. 0:03:52.560,0:03:53.700 Always move carefully. 0:03:53.700,0:03:55.380 When handling chemicals. 0:03:55.380,0:03:57.840 Keep coin top stoppers[br]between your fingers, 0:03:57.840,0:04:00.990 not on the bench where they[br]can pick up contaminants. 0:04:00.990,0:04:03.270 Hold bottles with your hand over the label 0:04:03.270,0:04:05.940 and replace stoppers immediately. 0:04:05.940,0:04:08.550 Covering the label keeps[br]drips from blurring it 0:04:08.550,0:04:10.770 or getting on your hands. 0:04:10.770,0:04:13.200 Set bottles out of the[br]way when you're finished. 0:04:13.200,0:04:15.150 So they won't get knocked to the floor. 0:04:18.840,0:04:21.300 When handling chemicals[br]always keep them away 0:04:21.300,0:04:24.176 from your face, never taste[br]anything to see what it is 0:04:24.176,0:04:26.790 and don't touch it or smell it directly 0:04:26.790,0:04:28.083 from the bottle either. 0:04:28.920,0:04:31.800 Small amounts of some[br]chemicals even vapors 0:04:31.800,0:04:35.223 can harm your eyes, mouth[br]and nasal membranes. 0:04:36.840,0:04:39.420 There's a safe way to smell[br]a chemical indirectly. 0:04:39.420,0:04:41.730 If your teacher gives you permission, 0:04:41.730,0:04:44.520 hold it away from your[br]face and waft the vapors 0:04:44.520,0:04:45.990 to your nose. 0:04:45.990,0:04:48.740 That way you won't get a[br]strong whiff of them directly. 0:04:50.520,0:04:52.770 Certain chemicals give off vapors. 0:04:52.770,0:04:55.710 They're called volatile chemicals. 0:04:55.710,0:04:57.630 You should work with harmful volatiles 0:04:57.630,0:04:59.220 under a fume hood. 0:04:59.220,0:05:01.820 Your teacher will tell you[br]what these chemicals are. 0:05:03.300,0:05:06.900 Chemicals should be kept[br]pure and uncontaminated. 0:05:06.900,0:05:08.580 One way to prevent contamination 0:05:08.580,0:05:10.923 is to use only clean glassware. 0:05:17.160,0:05:20.073 Another way is to only pour[br]out of a reagent bottle. 0:05:23.970,0:05:26.190 Never pour anything back in, 0:05:26.190,0:05:29.340 even excess chemicals you haven't used. 0:05:29.340,0:05:31.290 It's better to waste the excess 0:05:31.290,0:05:33.690 than to risk contaminating[br]the entire bottle 0:05:33.690,0:05:35.583 with particles from around the lab. 0:05:45.390,0:05:47.370 After measuring out a reagent, 0:05:47.370,0:05:49.920 you'll often have something left over, 0:05:49.920,0:05:52.391 instead of pouring it[br]back in the reagent bottle 0:05:52.391,0:05:55.413 dispose of it in the[br]proper waste container. 0:05:59.580,0:06:01.710 When drawing out chemicals with a pipette 0:06:01.710,0:06:05.610 don't use your mouth,[br]use a bulb or pipette. 0:06:05.610,0:06:07.920 You can collect the exact amount you need 0:06:07.920,0:06:10.203 and never have to come in contact with it. 0:06:18.510,0:06:20.400 At some point in your laboratory work, 0:06:20.400,0:06:22.620 you'll probably spill something, 0:06:22.620,0:06:25.380 you should report spills immediately. 0:06:25.380,0:06:27.120 Stay away from the spilled chemical 0:06:27.120,0:06:29.613 and let your teacher clean it up. 0:06:35.532,0:06:37.020 To keep a large spill from spreading 0:06:37.020,0:06:39.600 it's barricaded with an[br]absorbent material such 0:06:39.600,0:06:40.563 as kitty litter. 0:06:44.430,0:06:47.070 It's then either mopped up or covered over 0:06:47.070,0:06:48.753 completely with the absorbent. 0:06:55.620,0:06:58.443 The absorbent and chemical[br]can be swept up with a broom. 0:06:59.520,0:07:01.440 What's done with the residue depends on 0:07:01.440,0:07:03.780 the type of chemical it contains. 0:07:03.780,0:07:07.350 A lab should have a container[br]for each type of waste. 0:07:07.350,0:07:09.570 Don't throw waste chemicals down the sink 0:07:09.570,0:07:11.913 unless your teacher says it's all right. 0:07:15.960,0:07:17.880 Waste paper that's not contaminated 0:07:17.880,0:07:20.973 by chemicals goes into[br]conventional trashcan. 0:07:23.130,0:07:26.133 And broken glassware goes[br]into a separate container. 0:07:27.990,0:07:30.120 The last chemical handling safety rule 0:07:30.120,0:07:33.513 to keep in mind is to[br]clean up when finished. 0:07:41.490,0:07:44.160 Glassware should be thoroughly[br]scrubbed and rinsed, 0:07:44.160,0:07:47.253 so it's as clean as possible[br]for the next experiment. 0:07:48.900,0:07:51.090 Liquid puddles or powders left behind 0:07:51.090,0:07:54.120 on the lab bench can get on[br]the next person's clothing 0:07:54.120,0:07:58.200 or skin, wipe them up thoroughly 0:07:58.200,0:08:01.593 and throw the paper towels[br]away in the proper container. 0:08:04.650,0:08:08.220 And clean chemicals off[br]your hands before leaving. 0:08:08.220,0:08:10.410 There may be invisible chemical residues 0:08:10.410,0:08:12.030 that could damage your skin 0:08:12.030,0:08:14.553 or contaminate your food[br]the next time you eat. 0:08:19.230,0:08:21.153 Work with small containers. 0:08:22.080,0:08:24.873 Mix chemicals only when[br]your teacher says to. 0:08:25.830,0:08:29.040 Read and reread chemical labels. 0:08:29.040,0:08:31.803 Read instructions all[br]the way through first. 0:08:33.000,0:08:35.283 Use a work tray if your lab has them. 0:08:36.420,0:08:39.903 Move carefully and deliberately[br]when handling chemicals. 0:08:40.890,0:08:44.703 Add concentrated sulfuric[br]or phosphoric acid to water. 0:08:46.290,0:08:49.953 Hold coin top stoppers between[br]your fingers while pouring. 0:08:51.300,0:08:53.733 Hold bottles with your[br]hand over the label. 0:08:54.990,0:08:57.243 Replace stoppers immediately. 0:08:58.680,0:09:00.963 Keep chemicals away from your face. 0:09:02.790,0:09:05.763 Work with harmful volatile[br]chemicals under a hood. 0:09:07.530,0:09:11.103 Keep chemicals as pure and[br]uncontaminated as possible. 0:09:12.810,0:09:16.533 Draw out chemicals with a[br]pipette filler, never by mouth. 0:09:18.240,0:09:21.390 Notify your teacher to clean up spills. 0:09:21.390,0:09:23.463 Put waste in the proper container. 0:09:24.540,0:09:26.313 Clean up when finished. 0:09:35.730,0:09:38.130 The main heat source[br]in most chemistry labs 0:09:38.130,0:09:40.110 is the Bunsen burner. 0:09:40.110,0:09:44.280 It produces an open gas flame[br]burning at a high temperature. 0:09:44.280,0:09:45.360 There's always the danger 0:09:45.360,0:09:47.853 of an accident if it's not used properly. 0:09:50.640,0:09:52.598 For example it should never be used 0:09:52.598,0:09:54.870 to heat volatile organic liquids 0:09:54.870,0:09:56.793 that give off flammable vapors. 0:10:00.090,0:10:03.060 These substances should be[br]heated in a heating mantle 0:10:03.060,0:10:04.893 or a steam bath in a hood. 0:10:09.780,0:10:12.360 But for most other[br]substances a Bunsen burner 0:10:12.360,0:10:15.183 is an ideal heat source[br]when used properly. 0:10:17.220,0:10:19.680 There are several types of Bunsen burners, 0:10:19.680,0:10:21.993 but they all have the same basic parts. 0:10:25.860,0:10:29.070 The gas comes from an[br]outlet on the lab bench. 0:10:29.070,0:10:31.334 A rubber hose fits over the tip 0:10:31.334,0:10:34.503 and over a similar fitting[br]on the Bunsen burner. 0:10:35.880,0:10:38.130 Most burners have a valve at the bottom 0:10:38.130,0:10:40.083 to control the flow of gas. 0:10:41.370,0:10:44.910 Air inlets control the amount[br]of oxygen in the flame. 0:10:44.910,0:10:46.890 A wing top can be placed on the burner 0:10:46.890,0:10:48.453 to spread the flame out. 0:10:53.250,0:10:55.590 There are several[br]important rules to follow 0:10:55.590,0:10:58.350 to use a Bunsen burner safely. 0:10:58.350,0:11:01.200 First check the gas hose for cracks. 0:11:01.200,0:11:03.540 If you see any, get a new hose. 0:11:14.247,0:11:16.890 Make sure the hose fits[br]securely on the gas valve 0:11:16.890,0:11:18.303 and on the Bunsen burner. 0:11:19.680,0:11:22.530 The gas valve at the bottom[br]of the burner should be open. 0:11:23.910,0:11:27.423 You can light a Bunsen burner[br]with a striker or a match. 0:11:30.930,0:11:34.353 Open the gas line valve[br]and light the burner. 0:11:36.780,0:11:39.000 If the flames properly adjusted, 0:11:39.000,0:11:41.133 you can place the burner under your setup. 0:11:48.120,0:11:53.120 When using a match[br]strike it away from you. 0:11:53.640,0:11:56.131 Turn the gas on after the match is burning 0:11:56.131,0:11:59.733 that way, gas won't escape[br]while you're striking the match. 0:12:00.750,0:12:04.353 Light the gas from the side[br]so the match isn't blown out. 0:12:05.310,0:12:07.950 A yellow flame is too cool. 0:12:07.950,0:12:11.403 Opening the air holes lets in[br]more oxygen for combustion. 0:12:14.250,0:12:18.570 Adjust the bottom valve if the[br]flame is too large or small. 0:12:18.570,0:12:22.320 The flame should be blue[br]with a lighter inner cone. 0:12:22.320,0:12:25.713 The tip of the inner cone is[br]the hottest part of the flame. 0:12:33.120,0:12:35.245 If the flame begins to sputter or flare, 0:12:35.245,0:12:37.533 turn the gas off immediately. 0:12:41.940,0:12:45.243 Also turn the gas off immediately[br]if the flame goes out. 0:12:49.740,0:12:52.710 Unburned gas escaping[br]into the room could ignite 0:12:52.710,0:12:54.363 and cause an explosion. 0:12:56.220,0:12:58.800 Even when the burner seems[br]to be working properly, 0:12:58.800,0:13:02.853 if you smell gas turn it off. 0:13:05.490,0:13:08.850 Cracks or stars and[br]glassware are dangerous. 0:13:08.850,0:13:10.773 They can break open when it's heated. 0:13:17.670,0:13:20.250 So before you heat any glassware 0:13:20.250,0:13:22.923 check it carefully for cracks or stars. 0:13:27.930,0:13:30.390 Flat bottomed containers[br]are normally heated 0:13:30.390,0:13:32.613 on a wire screen on a ring stand. 0:13:33.870,0:13:36.174 Erlenmeyer flask and other[br]narrow neck containers 0:13:36.174,0:13:38.943 should be secure to[br]the stand with a clamp. 0:13:46.260,0:13:48.204 Test tubes can be heated in a water bath. 0:13:48.204,0:13:51.690 The water bath transfers[br]heat slowly and evenly 0:13:51.690,0:13:54.573 to the test tube and helps[br]keep it from boiling over. 0:13:58.939,0:14:01.530 You can also heat a test[br]tube directly in the flame. 0:14:01.530,0:14:04.080 Hold it at an angle while[br]moving it back and forth 0:14:04.080,0:14:06.450 to distribute the heat evenly. 0:14:06.450,0:14:08.730 Aim it away from yourself[br]and your neighbors 0:14:08.730,0:14:10.203 in case it boils over. 0:14:12.210,0:14:14.730 Only heat containers with openings. 0:14:14.730,0:14:16.770 A boiling liquid changes to gas 0:14:16.770,0:14:18.663 which must be able to escape. 0:14:20.074,0:14:22.080 Gas can't escape from a closed container. 0:14:22.080,0:14:24.423 And the pressure that[br]builds up can burst it. 0:14:27.450,0:14:30.570 Be extra careful when[br]working with heated equipment 0:14:30.570,0:14:33.060 hold hot glassware and beaker tongs. 0:14:33.060,0:14:34.593 Never your hands. 0:14:37.380,0:14:41.133 Remember that the wire screen[br]and ring stand are also hot. 0:14:44.250,0:14:47.490 If you don't have tongs[br]protect your hands with gloves 0:14:47.490,0:14:49.203 designed for hot glassware. 0:14:53.280,0:14:55.860 Keep them away from the flame. 0:14:55.860,0:14:57.570 Handle everything as if it's hot 0:14:57.570,0:15:00.180 if you've been using a Bunsen burner. 0:15:00.180,0:15:02.430 Glass and metal look the same when hot 0:15:02.430,0:15:04.143 as they do when they're cold. 0:15:10.440,0:15:12.870 Heat volatile organics in a heating mantle 0:15:12.870,0:15:16.653 or steam bath in a hood,[br]not over a Bunsen burner. 0:15:17.910,0:15:20.103 Check the gas hose for cracks. 0:15:21.360,0:15:23.910 Make sure the hose fit[br]securely on the gas valve 0:15:23.910,0:15:25.563 and Bunsen fittings. 0:15:27.600,0:15:30.153 Stand back from the[br]burner while lighting it. 0:15:31.440,0:15:33.573 Strike matches away from you. 0:15:34.770,0:15:37.503 Turn on the gas after lighting the match. 0:15:39.330,0:15:40.943 Turn the gas off immediately 0:15:40.943,0:15:44.640 if the flame sputters flares or goes out 0:15:44.640,0:15:46.353 or if you smell gas. 0:15:48.480,0:15:51.273 Check glassware for stars or cracks. 0:15:53.220,0:15:55.923 Clamp narrow necked[br]containers to the ring stand. 0:15:58.170,0:16:00.600 Move test tubes back and[br]forth through the flame 0:16:00.600,0:16:02.223 at an angle while heating. 0:16:04.350,0:16:06.273 Don't heat closed containers. 0:16:07.530,0:16:10.953 Hold hot glassware and[br]beaker tongs or hot mitts. 0:16:19.230,0:16:21.780 Thermometers are one of[br]the most important tools 0:16:21.780,0:16:23.790 in the chemistry laboratory. 0:16:23.790,0:16:24.870 They're easy to use, 0:16:24.870,0:16:26.948 but since they're usually made of glass, 0:16:26.948,0:16:29.163 they have to be handled properly. 0:16:30.990,0:16:33.767 One common misconception[br]is that lab thermometer 0:16:33.767,0:16:37.530 have to be shaken down[br]like medical thermometers. 0:16:37.530,0:16:41.643 Shaking is totally unnecessary[br]and it can be dangerous. 0:16:46.080,0:16:48.750 The liquid inside can[br]move freely up and down 0:16:48.750,0:16:50.493 on its own without shaking. 0:16:53.670,0:16:56.640 Some lab reactions take[br]place at higher temperatures 0:16:56.640,0:17:00.480 than an alcohol or mercury[br]thermometer can stand. 0:17:00.480,0:17:02.040 The temperature of oxidation 0:17:02.040,0:17:06.063 in a Bunsen burner flame is[br]around 600 degrees Celsius. 0:17:07.080,0:17:10.920 That high a temperature will[br]vaporize the liquid inside. 0:17:10.920,0:17:13.623 The resulting pressure[br]will break the glass. 0:17:17.100,0:17:20.070 But most lab experiments are[br]conducted at temperatures 0:17:20.070,0:17:25.070 from 120 degrees Celsius[br]down to minus 20 degrees. 0:17:25.290,0:17:27.842 And for that range, either[br]a mercury thermometer 0:17:27.842,0:17:31.323 or an alcohol thermometer is suitable. 0:17:40.884,0:17:44.250 No matter which type you use[br]always treat it carefully. 0:17:44.250,0:17:46.380 When you're finished with it, set it down 0:17:46.380,0:17:47.643 where it will be safe. 0:17:48.480,0:17:51.480 Lay it away from the edge of[br]the bench on a wire screen 0:17:51.480,0:17:53.943 or towel so it can't roll off. 0:18:00.420,0:18:02.670 When a thermometer breaks the glass 0:18:02.670,0:18:04.290 in any liquid that spills out 0:18:04.290,0:18:07.260 must be cleaned up and[br]disposed of properly. 0:18:07.260,0:18:09.213 This is a job for your teacher. 0:18:12.660,0:18:15.090 Glass fragments can be swept up. 0:18:15.090,0:18:17.940 If any alcohol happens[br]to escape from the glass 0:18:17.940,0:18:20.223 it can be wiped up with a paper towel. 0:18:28.290,0:18:30.480 Cleaning up a broken mercury thermometer 0:18:30.480,0:18:34.500 is more difficult and also[br]a job for your teacher. 0:18:34.500,0:18:39.390 Mercury is poisonous and it[br]won't soak into a paper towel. 0:18:39.390,0:18:42.393 Mercury vapors also can[br]escape into the air. 0:18:43.350,0:18:45.600 If you work with mercury thermometer, 0:18:45.600,0:18:46.933 your lab may be equipped with 0:18:46.933,0:18:49.683 a mercury cleanup kit or sponge. 0:18:58.710,0:19:01.320 The kit and broken glass[br]should be disposed of 0:19:01.320,0:19:02.823 in the proper container. 0:19:10.080,0:19:11.973 Don't shake thermometers. 0:19:12.810,0:19:15.210 Use thermometers only[br]in the temperature range 0:19:15.210,0:19:16.353 they're suited for. 0:19:17.760,0:19:19.650 Lay thermometer down on a towel 0:19:19.650,0:19:23.583 or wire screen to cool away[br]from the edge of the bench. 0:19:24.510,0:19:27.213 Let your teacher clean[br]up broken thermometers. 0:19:36.060,0:19:38.550 The most common lab injuries are cuts 0:19:38.550,0:19:41.763 from broken glass,[br]especially glass tubing. 0:19:42.870,0:19:45.720 A typical accident comes[br]from using too much force 0:19:45.720,0:19:48.213 to push a tube through[br]the hole in the stopper. 0:19:50.346,0:19:51.360 One way to avoid this kind of accident 0:19:51.360,0:19:53.133 is to use an inserter. 0:19:54.060,0:19:56.850 First dip the Teflon tip[br]in a glass lubricant, 0:19:56.850,0:19:58.380 such as glycerin. 0:19:58.380,0:20:00.870 Then push it through the stopper, 0:20:00.870,0:20:03.990 remove the tip and slide the tubing 0:20:03.990,0:20:05.913 through the hollow inserter shaft. 0:20:10.080,0:20:13.050 Removing the shaft[br]leaves the tubing behind. 0:20:13.050,0:20:15.270 Make sure to wash the[br]lubricant off the tubing 0:20:15.270,0:20:17.490 and stopper before using them. 0:20:17.490,0:20:20.763 And replace the Teflon tip[br]so it doesn't get lost. 0:20:23.040,0:20:25.230 To remove the tubing take out the tip 0:20:25.230,0:20:28.470 and lubricate the end of the hollow shaft. 0:20:28.470,0:20:31.020 Push it through the stopper[br]hole around the tubing. 0:20:36.641,0:20:38.070 Then slide the tubing[br]out through the shaft 0:20:38.070,0:20:40.110 and remove the inserter. 0:20:40.110,0:20:41.850 Remember to wash the lubricant off 0:20:41.850,0:20:44.613 before returning the stopper[br]and tubing to storage. 0:20:48.060,0:20:50.103 And don't forget to replace the tip. 0:20:53.640,0:20:55.710 If you don't have an inserter, 0:20:55.710,0:20:59.460 lubricate the tubing instead[br]and protect your hands 0:20:59.460,0:21:01.320 with leather gloves, 0:21:01.320,0:21:03.540 push the tubing gently through, 0:21:03.540,0:21:05.910 rotate it if there's any resistance. 0:21:05.910,0:21:08.130 Use the same care when removing it. 0:21:08.130,0:21:10.563 And don't forget to[br]wash off the lubricant. 0:21:16.560,0:21:18.780 Use an inserter to place glass tubing 0:21:18.780,0:21:20.613 in a stopper or remove it. 0:21:22.170,0:21:24.390 Or lubricate the tubing[br]and protect your hands 0:21:24.390,0:21:25.623 with leather gloves. 0:21:35.790,0:21:38.730 A centrifuge spins mixtures[br]around in test tubes 0:21:38.730,0:21:41.640 to separate solids from liquids. 0:21:41.640,0:21:44.055 The solids move out toward[br]the bottom of the tubes 0:21:44.055,0:21:46.083 and the liquid stays on top. 0:21:48.060,0:21:51.030 When the test tubes inside[br]aren't evenly distributed 0:21:51.030,0:21:53.883 the centrifuge is unbalanced. 0:22:02.070,0:22:05.940 It vibrates like a washing[br]machine with an unbalanced load. 0:22:05.940,0:22:07.830 If the vibration is bad enough 0:22:07.830,0:22:09.603 it can fall off the bench top. 0:22:15.210,0:22:19.980 To prevent vibration, a[br]centrifuge must be balanced. 0:22:19.980,0:22:22.950 If you're only centrifusion one test tube 0:22:22.950,0:22:26.133 place another one opposite it[br]with an equal amount of water. 0:22:27.840,0:22:31.053 Once the centrifuge is[br]balanced you can turn it on. 0:22:36.270,0:22:38.350 When it's finished, turn it off 0:22:40.620,0:22:43.530 and wait till it stops[br]spinning on its own. 0:22:43.530,0:22:46.443 Never try to stop a[br]centrifuge with your hand. 0:22:52.800,0:22:54.303 Place equally filled test tubes 0:22:54.303,0:22:56.373 in a centrifuge to balance it. 0:22:57.450,0:22:59.973 Don't try to stop the[br]spinning with your hand. 0:23:09.120,0:23:12.510 A safe lab session starts[br]with proper clothes. 0:23:12.510,0:23:14.160 You must wear clothing and equipment 0:23:14.160,0:23:16.710 that will protect you[br]from chemicals and flames. 0:23:16.710,0:23:19.173 And at the same time,[br]stay out of your way. 0:23:26.010,0:23:28.560 For example, sleeves that are too loose 0:23:28.560,0:23:30.300 can drag through a chemical puddle 0:23:30.300,0:23:31.713 or knock things over. 0:23:37.350,0:23:40.110 The wrong material is also dangerous. 0:23:40.110,0:23:42.510 As this mannequin demonstrates. 0:23:42.510,0:23:46.563 Fuzzy sweaters or filmy fabrics[br]can easily catch on fire. 0:23:52.830,0:23:56.160 Synthetics such as polyester[br]melt when they burn 0:23:56.160,0:23:57.693 and stick to the skin. 0:24:03.390,0:24:04.650 The right kind of clothing 0:24:04.650,0:24:07.710 includes sleeves and shirts[br]that fit fairly close, 0:24:07.710,0:24:10.770 but aren't too tight to restrict movement 0:24:10.770,0:24:13.380 and fabrics made of sturdy cotton or wool 0:24:13.380,0:24:16.023 that won't melt and stick to your skin. 0:24:17.250,0:24:20.158 A lab apron keeps most[br]splashes off your clothes 0:24:20.158,0:24:23.700 but you should still wear[br]older clothes underneath 0:24:23.700,0:24:26.223 in case any chemicals[br]get passed the apron. 0:24:27.690,0:24:30.150 Legs are vulnerable to chemical splashes 0:24:30.150,0:24:33.000 and broken glass if you drop something. 0:24:33.000,0:24:36.060 So long pants or a long[br]skirt should be worn 0:24:36.060,0:24:37.083 to protect them. 0:24:39.120,0:24:41.613 Open shoes, can't protect[br]your feet from spills. 0:24:41.613,0:24:44.823 Closed leather shoes are much better. 0:24:45.840,0:24:48.330 And shoes made of cloth or woven material 0:24:48.330,0:24:51.180 can absorb spills and[br]hold harmful chemicals 0:24:51.180,0:24:52.413 against your skin. 0:24:53.700,0:24:55.680 Besides wearing the right clothes. 0:24:55.680,0:24:57.570 There are other[br]precautions you should take 0:24:57.570,0:24:59.460 to avoid accidents. 0:24:59.460,0:25:01.800 Tie up loose long hair. 0:25:01.800,0:25:04.803 It could knock something[br]over or even catch fire. 0:25:06.000,0:25:08.580 Remove rings and watches. 0:25:08.580,0:25:11.970 They can trap corrosive[br]chemicals against your skin 0:25:11.970,0:25:14.343 and the chemicals can damage your jewelry. 0:25:16.560,0:25:18.960 Your eyes are the easiest to hurt 0:25:18.960,0:25:20.883 and the most important to protect. 0:25:23.010,0:25:25.950 Don't wear contact lenses in lab. 0:25:25.950,0:25:29.013 They may trap chemical[br]vapors against your eyes. 0:25:31.950,0:25:33.150 If that happens, 0:25:33.150,0:25:35.190 your eyelids may go into spasms 0:25:35.190,0:25:37.890 that make it impossible[br]to remove the lenses 0:25:37.890,0:25:39.543 and wash out the chemical. 0:25:42.600,0:25:44.730 Always wear goggles with side shields 0:25:44.730,0:25:46.980 to completely protect your eyes 0:25:46.980,0:25:49.173 even if you're already wearing glasses. 0:25:50.280,0:25:52.950 And finally protect your hands, 0:25:52.950,0:25:56.190 never use bare hands[br]with concentrated acids, 0:25:56.190,0:25:58.890 bases or other reactive chemicals 0:25:58.890,0:26:02.160 such as concentrated hydrogen peroxide. 0:26:02.160,0:26:03.240 Your teacher will tell you 0:26:03.240,0:26:06.333 what type of gloves to wear[br]to work with these chemicals. 0:26:07.620,0:26:10.920 With the right clothes and[br]protective equipment you can work 0:26:10.920,0:26:14.463 with laboratory chemicals[br]with confidence and safety. 0:26:19.950,0:26:22.860 Don't wear extremely loose clothing. 0:26:22.860,0:26:24.993 Fabrics should be sturdy and natural. 0:26:25.920,0:26:28.863 Wear older clothes and[br]cover them with a lab apron. 0:26:29.850,0:26:33.063 Wear a long pants or a long[br]skirt to cover your legs. 0:26:34.020,0:26:37.650 Wear closed leather shoes[br]to protect your feet. 0:26:37.650,0:26:39.303 Tie up long hair. 0:26:40.140,0:26:41.913 Remove rings and watches. 0:26:43.230,0:26:45.033 Take out contact lenses. 0:26:46.170,0:26:48.903 Cover your eyes with[br]goggles with side shields. 0:26:49.950,0:26:52.803 Protect your hands with[br]the right kind of gloves. 0:27:01.620,0:27:03.360 A chemistry laboratory is full 0:27:03.360,0:27:05.643 of beakers and bottles holding chemicals. 0:27:06.570,0:27:10.410 Fooling around can have[br]disastrous consequences. 0:27:10.410,0:27:12.615 You could scar yourself[br]or others for life. 0:27:12.615,0:27:14.793 Even cause blindness. 0:27:20.670,0:27:23.250 So the most important[br]rule of all in the lab 0:27:23.250,0:27:25.500 is no fooling around. 0:27:25.500,0:27:29.373 Don't run, push or[br]wrestle, or even move fast. 0:27:31.020,0:27:34.980 Even if you're not fooling[br]around, accidents can happen. 0:27:34.980,0:27:35.813 - Wait a second. 0:27:36.840,0:27:38.970 - [Narrator] Personal belongings[br]in the middle of aisles 0:27:38.970,0:27:40.113 can trip someone. 0:27:43.050,0:27:45.420 Even a job as simple as reading a burette 0:27:45.420,0:27:47.460 can lead to an accident. 0:27:47.460,0:27:49.830 For greatest accuracy your eyes should be 0:27:49.830,0:27:52.180 on the same level as the[br]number you're reading. 0:27:54.870,0:27:57.240 If you can't read a burette accurately 0:27:57.240,0:27:59.223 lower it down to eye level. 0:28:01.320,0:28:04.503 If you can't do that,[br]stand on a step stool. 0:28:07.230,0:28:08.640 There are behavioral rules 0:28:08.640,0:28:11.463 to protect you against[br]less obvious hazards too. 0:28:12.780,0:28:15.390 Applying makeup may seem harmless enough, 0:28:15.390,0:28:17.940 but chemicals and vapors[br]and spills in the lab 0:28:17.940,0:28:19.293 can contaminate it. 0:28:20.850,0:28:22.920 Then when you apply it to your face 0:28:22.920,0:28:24.900 you put on the chemical too. 0:28:24.900,0:28:27.333 So keep makeup outside the lab. 0:28:30.480,0:28:34.050 Eating and drinking in the lab[br]can cause similar problems. 0:28:34.050,0:28:38.043 Chemicals can contaminate your[br]food or splash into a drink. 0:28:39.120,0:28:41.798 - Guys, I think it's time to go to class. 0:28:41.798,0:28:42.683 - Can't be. 0:28:42.683,0:28:43.675 - It is. 0:28:43.675,0:28:44.508 (indistinct chattering) 0:28:44.508,0:28:45.540 - [Narrator] Get rid[br]of them before you come 0:28:45.540,0:28:46.893 into the chemistry lab. 0:28:52.800,0:28:54.573 Don't fool around in lab. 0:28:56.190,0:28:58.803 Keep aisles clear of personal belongings. 0:29:00.030,0:29:02.643 Stand on a step stool[br]when you have to reach. 0:29:03.990,0:29:05.643 Keep makeup in your purse. 0:29:07.020,0:29:09.453 Keep food and drinks outside. 0:29:19.800,0:29:21.720 In spite of safety precautions 0:29:21.720,0:29:24.993 people sometimes get careless[br]and accidents happen. 0:29:27.300,0:29:29.700 That's why a well-equipped chemistry lab 0:29:29.700,0:29:32.193 has emergency equipment[br]to take care of them. 0:29:33.270,0:29:34.740 If you've cut yourself 0:29:34.740,0:29:37.557 wash the wound to remove[br]any chemical traces. 0:29:37.557,0:29:41.283 Make sure there are no[br]pieces of glass in the cut. 0:29:42.480,0:29:45.393 Dry your skin carefully[br]so a bandage will stick. 0:29:47.100,0:29:49.890 Let your teacher put[br]the bandage on the cut. 0:29:49.890,0:29:53.040 Notify your teacher whenever[br]you have an accident 0:29:53.040,0:29:56.070 and make sure to get[br]immediate medical attention 0:29:56.070,0:29:58.083 after any injury in the lab. 0:30:03.060,0:30:07.083 Chemical spills and splashes[br]are also common lab accidents. 0:30:08.344,0:30:09.423 - Ah. 0:30:09.423,0:30:10.410 - Are you okay? 0:30:10.410,0:30:11.370 - My eyes. 0:30:11.370,0:30:13.470 - Let's go wash 'em out. 0:30:13.470,0:30:15.360 - [Narrator] If a chemical hits your eyes 0:30:15.360,0:30:18.183 wash them immediately[br]in an eye wash fountain. 0:30:19.080,0:30:21.094 Hold your eyes open and roll them around 0:30:21.094,0:30:23.433 so the water can wash them thoroughly. 0:30:24.270,0:30:26.070 You shouldn't be wearing contacts 0:30:26.070,0:30:27.990 but if you are get them out 0:30:27.990,0:30:31.560 as soon as you've given your[br]eyes a good initial rinsing. 0:30:31.560,0:30:35.100 Continue washing for at least 15 minutes. 0:30:35.100,0:30:38.523 Then see a doctor immediately[br]to check your eyes for damage. 0:30:41.190,0:30:43.518 Non corrosive chemical[br]splashes on bare skin 0:30:43.518,0:30:47.163 should be rinsed off in the[br]lab sink with plenty of water. 0:30:53.790,0:30:57.753 Spills of corrosive materials[br]require a lot more water. 0:30:58.950,0:31:02.160 Don't wait till you feel[br]pain from the chemical. 0:31:02.160,0:31:04.473 Head for the safety shower immediately. 0:31:06.390,0:31:09.363 Rinse your body thoroughly[br]as fast as possible. 0:31:17.160,0:31:19.203 Take off all your clothes. 0:31:21.090,0:31:23.700 Don't let modesty make your injury worse. 0:31:23.700,0:31:25.620 Your teacher will clear the other students 0:31:25.620,0:31:26.583 out of the room. 0:31:29.490,0:31:33.183 Stay under the shower[br]for at least 15 minutes. 0:31:35.580,0:31:38.880 Fires are always a potential[br]hazard in chemistry lab 0:31:38.880,0:31:42.210 especially when organic[br]liquids are involved. 0:31:42.210,0:31:44.310 Small fires and containers can often 0:31:44.310,0:31:45.933 be put out by covering them. 0:31:48.570,0:31:51.483 Turn off the burner so[br]the fire won't reignite. 0:32:00.210,0:32:03.300 Larger fires require a fire extinguisher. 0:32:03.300,0:32:06.783 It should be operated by a[br]teacher, not by a student. 0:32:23.910,0:32:24.933 - Hey, fire! 0:32:28.320,0:32:29.483 - Now let's leave. 0:32:30.780,0:32:33.180 - [Narrator] If the fire[br]is too large to control 0:32:33.180,0:32:34.890 clear out of the building. 0:32:34.890,0:32:37.440 Call the fire department[br]when you're safely outside 0:32:37.440,0:32:39.783 and tell them what chemicals are involved. 0:32:42.150,0:32:44.910 Clothing fires can be put[br]out in a couple of ways 0:32:44.910,0:32:46.743 as the mannequin will demonstrate. 0:32:50.910,0:32:53.103 The best way is in the safety shower. 0:32:58.969,0:33:01.590 If the shower's not close[br]by the rule is stop, 0:33:01.590,0:33:03.153 drop and roll. 0:33:05.220,0:33:06.903 The victim's weight on the fire. 0:33:08.691,0:33:11.220 Put some of it out and a[br]fire blanket gets the rest. 0:33:11.220,0:33:14.370 Flame should be kept away[br]from the victim's face. 0:33:14.370,0:33:15.660 Anyone who's been burned 0:33:15.660,0:33:18.153 must get medical attention immediately. 0:33:24.240,0:33:26.700 Clean and dry the skin around a cut 0:33:26.700,0:33:28.683 before a bandage is applied. 0:33:29.790,0:33:33.153 Rinse chemicals from your[br]eyes in the eye wash fountain. 0:33:34.650,0:33:37.368 Rinse chemicals from your[br]hands and arms with water 0:33:37.368,0:33:38.763 in the sink. 0:33:39.840,0:33:42.390 Remove your clothes on the[br]way to the safety shower 0:33:42.390,0:33:44.883 to rinse large spills from your body. 0:33:45.780,0:33:50.370 Extinguish small fires and[br]containers by covering them. 0:33:50.370,0:33:52.350 Let your teacher use an extinguisher 0:33:52.350,0:33:54.243 to put out larger fires. 0:33:55.200,0:33:57.903 Put out clothing fires[br]in the safety shower. 0:33:58.950,0:34:01.374 If there's no other way[br]to put out a clothing fire 0:34:01.374,0:34:04.740 use a fire blanket carefully[br]to keep flames away 0:34:04.740,0:34:06.243 from the face and neck. 0:34:13.020,0:34:15.660 The accidents in this[br]program may look serious 0:34:15.660,0:34:17.670 and many of them are, 0:34:17.670,0:34:19.660 but don't let the potential for danger 0:34:21.660,0:34:23.823 scare you away from chemistry lab. 0:34:27.060,0:34:29.190 A safe well run chemistry lab 0:34:29.190,0:34:32.700 is an interesting and[br]rewarding learning experience. 0:34:32.700,0:34:35.233 If you pay attention, use common sense 0:34:35.233,0:34:37.080 and follow the safety rules 0:34:37.080,0:34:39.780 you've seen here the chemistry laboratory 0:34:39.780,0:34:41.970 can be safer than your own home.