{"product_id":"how-does-nature-make-magnets","title":"How Does Nature Make Magnets?","description":"\u003ch3 data-start=\"732\" data-end=\"761\"\u003e\u003cstrong\u003eAn iron nail is not a magnet.\u003c\/strong\u003e\u003c\/h3\u003e\n\u003ch3 data-start=\"763\" data-end=\"820\"\u003e\u003cstrong\u003eYet with enough rubbing from a magnet, it can become one.\u003c\/strong\u003e\u003c\/h3\u003e\n\u003ch3 data-start=\"822\" data-end=\"874\"\u003e\u003cstrong\u003eBut this simple experiment raises a deeper question:\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp data-start=\"878\" data-end=\"956\"\u003e\u003cstrong\u003eIf magnets are made by magnetic fields, where did the first magnets come from?\u003c\/strong\u003e\u003c\/p\u003e\n\u003ch3 data-start=\"958\" data-end=\"1029\"\u003e\u003cstrong\u003eHow does nature create a permanently magnetized rock such as lodestone?\u003c\/strong\u003e\u003c\/h3\u003e\n\u003ch3 data-start=\"1031\" data-end=\"1112\"\u003e\u003cstrong\u003eTo answer that question, we first need to learn how to create a magnet ourselves.\u003c\/strong\u003e\u003c\/h3\u003e\n\u003ch1 data-section-id=\"qid1tg\" data-start=\"1119\" data-end=\"1136\"\u003eMaking a Magnet\u003c\/h1\u003e\n\u003cp data-start=\"1138\" data-end=\"1187\"\u003eThe experiment begins with an ordinary iron nail.\u003c\/p\u003e\n\u003cp data-start=\"1189\" data-end=\"1263\"\u003eUsing two bar magnets, the nail is repeatedly stroked in a particular way.\u003c\/p\u003e\n\u003cp data-start=\"1265\" data-end=\"1345\"\u003eThe opposite poles of the magnets are placed together at the center of the nail.\u003c\/p\u003e\n\u003cp data-start=\"1347\" data-end=\"1410\"\u003eThe magnets are then moved simultaneously toward opposite ends.\u003c\/p\u003e\n\u003cp data-start=\"1412\" data-end=\"1447\"\u003eThe process is repeated many times.\u003c\/p\u003e\n\u003cp data-start=\"1449\" data-end=\"1524\"\u003eWith each stroke, the magnetic domains inside the nail become more aligned.\u003c\/p\u003e\n\u003cp data-start=\"1526\" data-end=\"1612\"\u003eAfter roughly fifty repetitions, the nail begins to acquire a permanent magnetization.\u003c\/p\u003e\n\u003ch1 data-section-id=\"1jxdsdu\" data-start=\"1619\" data-end=\"1635\"\u003eAnother Method\u003c\/h1\u003e\n\u003cp data-start=\"1637\" data-end=\"1692\"\u003eA similar result can be achieved using only one magnet.\u003c\/p\u003e\n\u003cp data-start=\"1694\" data-end=\"1756\"\u003eOne pole is stroked repeatedly from the center toward one end.\u003c\/p\u003e\n\u003cp data-start=\"1758\" data-end=\"1813\"\u003eThe opposite pole is then stroked toward the other end.\u003c\/p\u003e\n\u003cp data-start=\"1815\" data-end=\"1895\"\u003eRepeated many times, this process also encourages alignment of magnetic domains.\u003c\/p\u003e\n\u003cp data-start=\"1897\" data-end=\"1923\"\u003eThe principle is the same:\u003c\/p\u003e\n\u003cp data-start=\"1925\" data-end=\"1993\"\u003eA magnetic field re-organizes the internal structure of the material.\u003c\/p\u003e\n\u003ch1 data-section-id=\"1g6yvp1\" data-start=\"2000\" data-end=\"2031\"\u003eDid the Nail Become a Magnet?\u003c\/h1\u003e\n\u003cp data-start=\"2033\" data-end=\"2092\"\u003eTo test the result, paper clips were brought near the nail.\u003c\/p\u003e\n\u003cp data-start=\"2094\" data-end=\"2118\"\u003eThe nail attracted them.\u003c\/p\u003e\n\u003cp data-start=\"2120\" data-end=\"2160\"\u003eOne end of a paper clip could be lifted.\u003c\/p\u003e\n\u003cp data-start=\"2162\" data-end=\"2195\"\u003eHowever, the attraction was weak.\u003c\/p\u003e\n\u003cp data-start=\"2197\" data-end=\"2261\"\u003eThe nail could not easily lift the clip completely into the air.\u003c\/p\u003e\n\u003cp data-start=\"2263\" data-end=\"2312\"\u003eThe experiment had succeeded, but only partially.\u003c\/p\u003e\n\u003cp data-start=\"2314\" data-end=\"2355\"\u003eA weak permanent magnet had been created.\u003c\/p\u003e\n\u003ch1 data-section-id=\"9xawsf\" data-start=\"2362\" data-end=\"2394\"\u003eWhat Happened Inside the Nail?\u003c\/h1\u003e\n\u003cp data-start=\"2396\" data-end=\"2462\"\u003eMagnetic materials contain countless microscopic magnetic domains.\u003c\/p\u003e\n\u003cp data-start=\"2464\" data-end=\"2485\"\u003eBefore magnetization:\u003c\/p\u003e\n\u003cul data-start=\"2487\" data-end=\"2554\"\u003e\n\u003cli data-section-id=\"jie1df\" data-start=\"2487\" data-end=\"2522\"\u003eDomains point in many directions.\u003c\/li\u003e\n\u003cli data-section-id=\"z00g6m\" data-start=\"2523\" data-end=\"2554\"\u003eTheir effects largely cancel.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp data-start=\"2556\" data-end=\"2577\"\u003eDuring magnetization:\u003c\/p\u003e\n\u003cul data-start=\"2579\" data-end=\"2622\"\u003e\n\u003cli data-section-id=\"1boq6b0\" data-start=\"2579\" data-end=\"2622\"\u003eMore domains align in the same direction.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp data-start=\"2624\" data-end=\"2680\"\u003eThe material begins to behave as a single larger magnet.\u003c\/p\u003e\n\u003cp data-start=\"2682\" data-end=\"2734\"\u003eThe stronger the alignment, the stronger the magnet.\u003c\/p\u003e\n\u003ch1 data-section-id=\"c69a22\" data-start=\"2741\" data-end=\"2760\"\u003eA Deeper Question\u003c\/h1\u003e\n\u003cp data-start=\"2762\" data-end=\"2805\"\u003eThe experiment reveals something important:\u003c\/p\u003e\n\u003cblockquote data-start=\"2807\" data-end=\"2865\"\u003e\n\u003cp data-start=\"2809\" data-end=\"2865\"\u003eA magnetic field is needed to create a permanent magnet.\u003c\/p\u003e\n\u003c\/blockquote\u003e\n\u003cp data-start=\"2867\" data-end=\"2922\"\u003eBut where does that magnetic field come from in nature?\u003c\/p\u003e\n\u003cp data-start=\"2924\" data-end=\"2958\"\u003eEarth itself has a magnetic field.\u003c\/p\u003e\n\u003cp data-start=\"2960\" data-end=\"3002\"\u003eHowever, Earth's field is relatively weak.\u003c\/p\u003e\n\u003cp data-start=\"3004\" data-end=\"3113\"\u003eIf the Earth's field alone were sufficient, many ordinary iron objects would gradually become strong magnets.\u003c\/p\u003e\n\u003cp data-start=\"3115\" data-end=\"3136\"\u003eThat does not happen.\u003c\/p\u003e\n\u003cp data-start=\"3138\" data-end=\"3183\"\u003eSo natural lodestones require something more.\u003c\/p\u003e\n\u003ch1 data-section-id=\"2wxr5m\" data-start=\"3190\" data-end=\"3222\"\u003eCould Lightning Be the Answer?\u003c\/h1\u003e\n\u003cp data-start=\"3224\" data-end=\"3257\"\u003eOne possible source is lightning.\u003c\/p\u003e\n\u003cp data-start=\"3259\" data-end=\"3304\"\u003eLightning carries enormous electric currents.\u003c\/p\u003e\n\u003cp data-start=\"3306\" data-end=\"3372\"\u003eAs we know, electric currents generate magnetic fields.\u003c\/p\u003e\n\u003cp data-start=\"3374\" data-end=\"3469\"\u003eA lightning strike can therefore create an extremely intense magnetic field for a brief moment.\u003c\/p\u003e\n\u003cp data-start=\"3471\" data-end=\"3547\"\u003eSuch fields may be strong enough to magnetize suitable minerals permanently.\u003c\/p\u003e\n\u003cp data-start=\"3549\" data-end=\"3629\"\u003eThis idea has long interested geophysicists studying naturally magnetized rocks.\u003c\/p\u003e\n\u003ch1 data-section-id=\"1lh1zqn\" data-start=\"3636\" data-end=\"3660\"\u003eThe Role of Hysteresis\u003c\/h1\u003e\n\u003cp data-start=\"3662\" data-end=\"3725\"\u003eThe answer involves more than simply applying a magnetic field.\u003c\/p\u003e\n\u003cp data-start=\"3727\" data-end=\"3786\"\u003eMagnetic materials remember part of their magnetic history.\u003c\/p\u003e\n\u003cp data-start=\"3788\" data-end=\"3823\"\u003eThis behavior is called hysteresis.\u003c\/p\u003e\n\u003cp data-start=\"3825\" data-end=\"3862\"\u003eWhen the external field is increased:\u003c\/p\u003e\n\u003cul data-start=\"3864\" data-end=\"3925\"\u003e\n\u003cli data-section-id=\"it1wde\" data-start=\"3864\" data-end=\"3886\"\u003eMagnetization grows.\u003c\/li\u003e\n\u003cli data-section-id=\"3pnoj2\" data-start=\"3887\" data-end=\"3925\"\u003eDomains become increasingly aligned.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp data-start=\"3927\" data-end=\"4004\"\u003eIf the field becomes strong enough, the material reaches magnetic saturation.\u003c\/p\u003e\n\u003cp data-start=\"4006\" data-end=\"4065\"\u003eRemoving the field does not completely erase the alignment.\u003c\/p\u003e\n\u003cp data-start=\"4067\" data-end=\"4100\"\u003eA residual magnetization remains.\u003c\/p\u003e\n\u003cp data-start=\"4102\" data-end=\"4151\"\u003eThis remaining magnetization is called remanence.\u003c\/p\u003e\n\u003ch1 data-section-id=\"1oimcwx\" data-start=\"4158\" data-end=\"4172\"\u003eThe Key Idea\u003c\/h1\u003e\n\u003cp data-start=\"4174\" data-end=\"4231\"\u003eA weak magnetic field may align some domains temporarily.\u003c\/p\u003e\n\u003cp data-start=\"4233\" data-end=\"4370\"\u003eBut to create a strong permanent magnet, the applied field must often be large enough to drive the material close to magnetic saturation.\u003c\/p\u003e\n\u003cp data-start=\"4372\" data-end=\"4456\"\u003eOnly then does significant remanent magnetization remain after the field is removed.\u003c\/p\u003e\n\u003cp data-start=\"4458\" data-end=\"4476\"\u003eThis explains why:\u003c\/p\u003e\n\u003cul data-start=\"4478\" data-end=\"4565\"\u003e\n\u003cli data-section-id=\"1qzaiui\" data-start=\"4478\" data-end=\"4513\"\u003eWeak fields produce weak magnets.\u003c\/li\u003e\n\u003cli data-section-id=\"16j4z6v\" data-start=\"4514\" data-end=\"4565\"\u003eStrong fields produce stronger permanent magnets.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp data-start=\"5398\" data-end=\"5482\"\u003e\u003cstrong\u003eThe most interesting outcome of the experiment is not that the nail became magnetic.\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp data-start=\"5484\" data-end=\"5520\"\u003e\u003cstrong\u003eIt is the new question that emerges:\u003c\/strong\u003e\u003c\/p\u003e\n\u003cblockquote data-start=\"5522\" data-end=\"5605\"\u003e\n\u003cp data-start=\"5524\" data-end=\"5605\"\u003e\u003cstrong\u003eWhat natural process produces magnetic fields strong enough to create lodestones?\u003c\/strong\u003e\u003c\/p\u003e\n\u003c\/blockquote\u003e\n\u003cp data-start=\"5607\" data-end=\"5632\"\u003e\u003cstrong\u003ePossible answers include:\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul data-start=\"5634\" data-end=\"5745\"\u003e\n\u003cli data-section-id=\"semleh\" data-start=\"5634\" data-end=\"5653\" style=\"font-weight: bold;\"\u003e\u003cstrong\u003eLightning strikes\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli data-section-id=\"z9e1cr\" data-start=\"5654\" data-end=\"5676\" style=\"font-weight: bold;\"\u003e\u003cstrong\u003eGeological processes\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli data-section-id=\"18e56vg\" data-start=\"5677\" data-end=\"5704\" style=\"font-weight: bold;\"\u003e\u003cstrong\u003eAncient volcanic activity\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli data-section-id=\"1w2sd30\" data-start=\"5705\" data-end=\"5745\" style=\"font-weight: bold;\"\u003e\u003cstrong\u003eStrong localized magnetic environments\u003c\/strong\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp data-start=\"5747\" data-end=\"5858\"\u003e\u003cstrong\u003eThe experiment turns a simple iron nail into a gateway toward understanding natural magnets found in the Earth.\u003c\/strong\u003e\u003c\/p\u003e","brand":"Geometers","offers":[{"title":"Default Title","offer_id":46107425046664,"sku":null,"price":0.0,"currency_code":"INR","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0725\/3891\/4952\/files\/4_dc20b116-6b66-45d5-9024-3f80223eeb40.jpg?v=1781255749","url":"https:\/\/geometers.in\/products\/how-does-nature-make-magnets","provider":"Geometers","version":"1.0","type":"link"}