1 00:00:01,260 --> 00:00:21,800 [Music] 2 00:00:24,160 --> 00:00:24,479 Hi 3 00:00:24,480 --> 00:00:26,799 I'm Suni Williams and I'm an astronaut 4 00:00:26,800 --> 00:00:28,239 who's lived and worked aboard the 5 00:00:28,240 --> 00:00:29,999 International Space Station, 6 00:00:30,000 --> 00:00:32,238 an amazing research laboratory that's 7 00:00:32,239 --> 00:00:34,879 orbiting the earth about 250 miles above 8 00:00:34,880 --> 00:00:35,919 us. 9 00:00:35,920 --> 00:00:37,679 While we're at the space station we 10 00:00:37,680 --> 00:00:39,119 astronauts live 11 00:00:39,120 --> 00:00:42,159 and work in a microgravity environment. 12 00:00:42,160 --> 00:00:44,159 Do you think the laws of physics will 13 00:00:44,160 --> 00:00:45,999 hold up in the space station while 14 00:00:46,000 --> 00:00:48,238 experiencing microgravity? 15 00:00:48,239 --> 00:00:50,238 Let's check with nasa astronaut Mark 16 00:00:50,239 --> 00:00:52,398 Vande Hei on the International Space Station 17 00:00:52,399 --> 00:00:58,319 to find out. 18 00:00:58,320 --> 00:01:00,398 Newton's first law of motion says an 19 00:01:00,399 --> 00:01:01,358 object at rest 20 00:01:01,359 --> 00:01:03,759 tends to stay at rest unless acted on by 21 00:01:03,760 --> 00:01:04,659 an outside force. 22 00:01:04,660 --> 00:01:06,559 [Music] 23 00:01:06,560 --> 00:01:10,239 Also, an object in motion 24 00:01:10,240 --> 00:01:12,639 tends to stay in motion unless acted on 25 00:01:12,640 --> 00:01:14,798 by an outside force 26 00:01:14,799 --> 00:01:17,439 like my finger. 27 00:01:20,159 --> 00:01:22,478 Let's look at this from another angle. 28 00:01:22,479 --> 00:01:24,239 Over time the International Space 29 00:01:24,240 --> 00:01:26,478 Station slows down from experiencing a 30 00:01:26,479 --> 00:01:28,639 very small amount of drag, 31 00:01:28,640 --> 00:01:32,239 or force from a tiny amount of atomic 32 00:01:32,240 --> 00:01:33,999 oxygen in space. 33 00:01:34,000 --> 00:01:36,319 This is like the force you feel from the 34 00:01:36,320 --> 00:01:38,399 air if you stick your hand out of a 35 00:01:38,400 --> 00:01:39,599 moving car. 36 00:01:39,600 --> 00:01:42,158 Because of this the space station does 37 00:01:42,159 --> 00:01:44,398 what we call a re-boost. 38 00:01:44,399 --> 00:01:46,798 A reboost uses rocket engines to put a 39 00:01:46,799 --> 00:01:48,798 force on the space station. 40 00:01:48,799 --> 00:01:51,679 This allows it to speed up just a little 41 00:01:51,680 --> 00:01:54,239 to remain in orbit around the earth. 42 00:01:54,240 --> 00:01:56,478 Let's join nasa astronaut Jeff Williams 43 00:01:56,479 --> 00:01:58,559 to check out what happens to the objects 44 00:01:58,560 --> 00:02:00,078 inside the space station 45 00:02:00,079 --> 00:02:03,039 when it begins. Now the way i'm going to 46 00:02:03,040 --> 00:02:04,798 demonstrate the acceleration that comes 47 00:02:04,799 --> 00:02:06,559 during the reboost is by using this 48 00:02:06,560 --> 00:02:07,359 camera 49 00:02:07,360 --> 00:02:09,839 uh 800 millimeter lens. So it's it's 50 00:02:09,840 --> 00:02:10,878 pretty massive 51 00:02:10,879 --> 00:02:13,999 actually and you can see i can float it 52 00:02:18,879 --> 00:02:17,520 here 53 00:02:17,520 --> 00:02:18,878 now so the camera's not going to go 54 00:02:18,879 --> 00:02:20,639 anywhere. It's just going to slowly drift 55 00:02:20,640 --> 00:02:23,119 due to the ventilation or or if i put 56 00:02:23,120 --> 00:02:23,919 any 57 00:02:23,920 --> 00:02:26,238 uh velocity into it it'll drift out of 58 00:02:26,239 --> 00:02:27,598 the scene. But i'm going to try to hold 59 00:02:27,599 --> 00:02:28,639 it here steady 60 00:02:28,640 --> 00:02:30,559 and you can see that it stays very 61 00:02:30,560 --> 00:02:31,919 steady. 62 00:02:31,920 --> 00:02:34,839 There's my camera I'm setting it up for 63 00:02:34,840 --> 00:02:35,999 ignition. 64 00:02:36,000 --> 00:02:38,238 There it goes it actually came a little 65 00:02:38,239 --> 00:02:40,238 bit early. 66 00:02:40,239 --> 00:02:42,719 Now watch the camera accelerate toward 67 00:02:42,720 --> 00:02:43,759 you. 68 00:02:43,760 --> 00:02:45,199 There it goes i'm going to reach out and 69 00:02:45,200 --> 00:02:47,199 grab it and bring it back 70 00:02:47,200 --> 00:02:50,479 in the view here and i'm holding it i'm 71 00:02:50,480 --> 00:02:52,479 actually feeling the acceleration 72 00:02:52,480 --> 00:02:55,039 i'm gonna let go again and here it goes. 73 00:02:55,040 --> 00:02:57,840 It's gonna take off. 74 00:02:58,640 --> 00:03:00,829 I'll try not to let it hit you. 75 00:03:00,830 --> 00:03:03,279 [Music] 76 00:03:03,280 --> 00:03:06,239 Just going to miss you. 77 00:03:07,280 --> 00:03:09,919 Yeah i'm going to let go now and here i 78 00:03:09,920 --> 00:03:11,518 go drifting back toward you again. 79 00:03:11,519 --> 00:03:13,389 So the acceleration applies to me too. 80 00:03:13,390 --> 00:03:16,639 [Music] 81 00:03:16,640 --> 00:03:19,598 Reached our 2.7 meters per second that 82 00:03:19,599 --> 00:03:20,079 we 83 00:03:20,080 --> 00:03:21,839 desired and now if i let go of the 84 00:03:21,840 --> 00:03:24,479 camera it's not going anywhere so the 85 00:03:24,480 --> 00:03:25,999 burn is over. 86 00:03:26,000 --> 00:03:28,399 Reboost complete. We'll stay in orbit for 87 00:03:28,400 --> 00:03:30,399 a little while longer. 88 00:03:30,400 --> 00:03:32,158 Can you use Newton's first law to 89 00:03:32,159 --> 00:03:34,238 explain why the camera began moving 90 00:03:34,239 --> 00:03:36,158 without an astronaut putting a force 91 00:03:36,159 --> 00:03:38,079 directly on it? 92 00:03:38,080 --> 00:03:40,479 I'm going to send you back to class so 93 00:03:40,480 --> 00:03:42,639 you can start to investigate this with 94 00:03:42,640 --> 00:03:44,158 the classroom connection 95 00:03:44,159 --> 00:03:47,359 found at nasa.gov/stemonstrations. 96 00:03:47,360 --> 00:03:49,279 Thanks for exploring a little physics on 97 00:03:49,280 --> 00:03:51,199 the space station with us today.