1 00:00:00,000 --> 00:00:07,000 Hi, Bianca. Thanks for meeting me here. I had a taping earlier today. 2 00:00:07,000 --> 00:00:11,000 That's cool. I've had a little bit of experience in front of cameras. 3 00:00:11,000 --> 00:00:14,000 Dr. Adamant, we learned about density currents, 4 00:00:14,000 --> 00:00:17,000 but we need to learn more about surface currents. 5 00:00:17,000 --> 00:00:19,000 So what exactly is a surface current? 6 00:00:19,000 --> 00:00:22,000 A surface current is water moving near the ocean's surface, 7 00:00:22,000 --> 00:00:24,000 above what we call the thermocline. 8 00:00:24,000 --> 00:00:28,000 Thermocline. I know that therm has something to do with temperature. 9 00:00:28,000 --> 00:00:31,000 Right. And cline means change. 10 00:00:31,000 --> 00:00:34,000 So the thermocline is a region of temperature change. 11 00:00:34,000 --> 00:00:36,000 Where is the thermocline? 12 00:00:36,000 --> 00:00:39,000 Typically between 50 and 150 meters deep. 13 00:00:39,000 --> 00:00:41,000 So how do surface currents form? 14 00:00:41,000 --> 00:00:46,000 Friction between the wind and the surface water causes that water to move. 15 00:00:46,000 --> 00:00:50,000 We learned in the case of the mysterious red light about global wind patterns, 16 00:00:50,000 --> 00:00:54,000 and that winds blow in a certain direction depending upon where they're located on Earth. 17 00:00:54,000 --> 00:01:00,000 Right. For example, the trade winds push the surface currents around in the tropics. 18 00:01:00,000 --> 00:01:02,000 But are there other factors? 19 00:01:02,000 --> 00:01:06,000 Sure. Because the Earth rotates, there's turning due to the Coriolis effect. 20 00:01:06,000 --> 00:01:10,000 Isn't that when the wind is deflected to the right in the northern hemisphere 21 00:01:10,000 --> 00:01:12,000 and the left in the southern hemisphere? 22 00:01:12,000 --> 00:01:16,000 Yes. And another factor that steers currents is the topography, 23 00:01:16,000 --> 00:01:19,000 the hills and valleys on the ocean floor. 24 00:01:19,000 --> 00:01:23,000 How does the topography underwater affect the surface currents? 25 00:01:23,000 --> 00:01:24,000 I'll show you. 26 00:01:28,000 --> 00:01:30,000 Sit on the stool. 27 00:01:31,000 --> 00:01:36,000 Now don't try this without an adult, but I want you to stick your arms and legs out. 28 00:01:36,000 --> 00:01:40,000 And once I spin you, I want you to bring your arms and legs in close to your body. 29 00:01:40,000 --> 00:01:42,000 Okay? You ready? 30 00:01:50,000 --> 00:01:51,000 What happened? 31 00:01:51,000 --> 00:01:55,000 I spun slower when my arms and legs were out and faster when they were in. 32 00:01:58,000 --> 00:02:00,000 Topography does the same thing to currents. 33 00:02:00,000 --> 00:02:03,000 If a current flows over an underwater mountain, 34 00:02:03,000 --> 00:02:06,000 the water column gets flattened and compresses. 35 00:02:06,000 --> 00:02:08,000 That's you with your legs out. 36 00:02:08,000 --> 00:02:12,000 The water spins differently, and the currents get deflected. 37 00:02:12,000 --> 00:02:15,000 Why are some surface currents cold and some others warm? 38 00:02:15,000 --> 00:02:18,000 It depends on where the water's coming from. 39 00:02:18,000 --> 00:02:21,000 If it's coming from the poles, it's cold. 40 00:02:21,000 --> 00:02:23,000 If it's from the tropics, it's warm. 41 00:02:23,000 --> 00:02:26,000 Do warm and cold currents affect the climate of an area? 42 00:02:26,000 --> 00:02:29,000 That's a good question, Bianca. Yes, they do. 43 00:02:29,000 --> 00:02:33,000 For example, Ireland is pretty far north, and you might expect it to be cold there. 44 00:02:33,000 --> 00:02:36,000 But the Gulf Stream flows past Ireland, 45 00:02:36,000 --> 00:02:40,000 and the warm water heats the air, which helps to create a surprisingly mild climate. 46 00:02:40,000 --> 00:02:43,000 They even have palm trees in Ireland. 47 00:02:43,000 --> 00:02:44,000 Really? 48 00:02:45,000 --> 00:02:47,000 With currents located in every ocean, 49 00:02:47,000 --> 00:02:51,000 I guess they could be responsible for bringing the tennis shoes and oil to our beach. 50 00:02:51,000 --> 00:02:54,000 It's possible, but you've got to be careful. 51 00:02:54,000 --> 00:02:57,000 The same current can transport things to different places. 52 00:02:57,000 --> 00:02:59,000 How does that happen? 53 00:03:09,000 --> 00:03:13,000 You drop the balls at the same time and all in about the same place. 54 00:03:13,000 --> 00:03:16,000 They ended up in different places. Why? 55 00:03:16,000 --> 00:03:19,000 Is it because there are so many different variables, 56 00:03:19,000 --> 00:03:22,000 such as the pits in the pavement or even the shape of the ball? 57 00:03:22,000 --> 00:03:26,000 Exactly. The same thing happens in the ocean. 58 00:03:26,000 --> 00:03:30,000 Tiny variations in the current can lead to large differences 59 00:03:30,000 --> 00:03:33,000 where the current might actually move things like your tennis shoes. 60 00:03:33,000 --> 00:03:37,000 Wow, that's amazing. I'm curious. 61 00:03:37,000 --> 00:03:39,000 Why does NASA study currents? 62 00:03:39,000 --> 00:03:42,000 First, oceans have the greatest influence on climate. 63 00:03:42,000 --> 00:03:46,000 And only from space can we monitor the vast oceans on a global scale 64 00:03:46,000 --> 00:03:50,000 and monitor critical changes in the currents and the heat storage. 65 00:03:50,000 --> 00:03:52,000 Why is that so important? 66 00:03:52,000 --> 00:03:55,000 Well, the oceans cover 70 percent of the Earth, 67 00:03:55,000 --> 00:03:59,000 and the currents in the ocean are an important part of the water cycle. 68 00:03:59,000 --> 00:04:03,000 Any change in the water cycle can cause major consequences on our Earth. 69 00:04:03,000 --> 00:04:05,000 How does NASA monitor the ocean? 70 00:04:05,000 --> 00:04:11,000 We use different satellites to monitor things like currents, waves, temperature, 71 00:04:11,000 --> 00:04:13,000 and pretty soon even salinity. 72 00:04:13,000 --> 00:04:15,000 That's really interesting. 73 00:04:15,000 --> 00:04:19,000 I'm always amazed at all the research NASA does to help protect our Earth. 74 00:04:19,000 --> 00:04:22,000 Thanks, Dr. Adamek. This information has been very helpful. 75 00:04:22,000 --> 00:04:26,000 You're welcome. And call if you have any more questions.