00:02Oh, hey, hi. I'm Chris at Chris and welcome to So Cool Science.
00:06Science you can do at home.
00:08Believe it or not, I am laying above a solid metal core and, oh yeah, I'm going over today's science
00:15file.
00:16In today's science file, it says...
00:19How do we know the Earth has a core?
00:24Well, that's an awesome question. Try this.
00:33You will need a bowl, some water, and a bottle cap.
00:39Okay, so this is a good question because nobody has ever seen the center of the Earth.
00:44And how can you say there is something that nobody's ever seen?
00:48You know, unless you're Christian.
00:50But unlike them, I'm going to actually show you 100% proof that the Earth definitely has a core even
00:56though nobody's ever seen it.
00:58So, start by getting yourself one of these round bowls.
01:02Why round? Because the Earth is round.
01:06Okay, so next you're going to get yourself one of these 3-liter bottles of water.
01:09Oh, and by the way, you're not only going to use the water, you're going to actually use the cap.
01:12So, hold onto the cap. I really need to start working out.
01:17Okay, start by pouring your water into your bowl.
01:20Okay, so now I'm going to go ahead and make an earthquake on one side of the bowl.
01:27Yeah, an earthquake.
01:33Okay, get that bottle cap, and you're going to place the bottle cap in the center of your bowl.
01:38Kind of like this.
01:46Okay, so now I'm going to make another earthquake.
01:53Okay, so what does this have to do with the fact that we know there's a core in the center
01:57of the Earth even though no one has ever seen one?
02:00And what other evidence is there that there's a core at the center of our Earth?
02:05Well, don't look at me. Take a closer look at this.
02:12Scientists know the Earth has a solid core because they have observed earthquakes and their effects here on Earth.
02:18When an earthquake happens on one side of the Earth, the waves that travel through the mantle get blocked by
02:23something solid.
02:24If the Earth didn't have something solid in its center, the waves would travel straight through the mantle to the
02:30other side of the Earth and they would feel the earthquake there.
02:34Radiation from the Sun interacts with a magnetic field surrounding the Earth.
02:37This means the Earth's core is made of iron as well as nickel and a small amount of cobalt.
02:42We also know the temperature of the core is 6,000 degrees Celsius.
02:46By measuring the temperature of iron put under the same amounts of pressure as the Earth's core is at the
02:52center of the Earth.
02:52We can tell how big the Earth's core is by measuring the density of the planet.
02:57We know how dense the Earth's crust is, and we know how dense magma is, so the leftover density would
03:03make up the 6,350 kilometer wide double core.
03:07We know there is a double core for measuring the seismic energy bouncing off the inner solid core.
03:13And the leftover calculations of the full density of the Earth would make up the outer core.
03:18By studying earthquakes, magnetics, and density, scientists can be 100% sure there is a core in the center of
03:24the Earth without ever observing it directly.
03:27So now you know how science proves the unseeable.
03:31You know, being able to see that there is an Earth core right at home is why science is so
03:39cool.
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