{"id":63141,"date":"2026-05-07T04:30:43","date_gmt":"2026-05-06T19:30:43","guid":{"rendered":"https:\/\/phys-edu.net\/wp\/?p=63141"},"modified":"2026-05-07T04:30:43","modified_gmt":"2026-05-06T19:30:43","slug":"gravity-challenge-do-feathers-and-steel-balls-really-fall-at-the-same-speed","status":"publish","type":"post","link":"https:\/\/phys-edu.net\/wp\/?p=63141&lang=en","title":{"rendered":"Gravity Challenge: Do Feathers and Steel Balls Really Fall at the Same Speed?"},"content":{"rendered":"<p style=\"text-align: center;\"><span style=\"color: #339966;\"><strong>I\u2019m Ken Kuwako, your science trainer. Every day is an experiment.<\/strong><\/span><\/p>\n<p>\u201cIf you drop two objects with different weights at the same time, which one hits the ground first?\u201d \u2014 how would you answer?<\/p>\n<p>Many people might say the heavier one falls faster. But in reality, that\u2019s not the case. There\u2019s a simple tool you can use at home to see this surprising phenomenon for yourself: it\u2019s called the BeeSpi.<\/p>\n<h3>What is BeeSpi?<\/h3>\n<p> <img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-27151 aligncenter\" src=\"https:\/\/phys-edu.net\/wp\/wp-content\/uploads\/2016\/04\/26579fbf8d51281768c9c08a5a36682a.jpg\" alt=\"\" width=\"225\" height=\"252\" \/> <\/p>\n<p style=\"text-align: center;\">Do you have a BeeSpi?<\/p>\n<p>Have you ever heard of BeeSpi?<br \/>\nBeeSpi is a simple, U-shaped speed measuring device. Inside the frame are two sensors, and when an object passes through the opening, it measures its speed.<\/p>\n<p>Originally, it was designed to measure the speed of toys like marbles, but thanks to its convenience, it eventually found its way into science experiments. It\u2019s even exported worldwide. One of its biggest advantages is that, despite being a speedometer, it\u2019s very affordable.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-63137 aligncenter\" src=\"https:\/\/phys-edu.net\/wp\/wp-content\/uploads\/2020\/03\/\u30b9\u30af\u30ea\u30fc\u30f3\u30b7\u30e7\u30c3\u30c8-2026-05-07-4.24.23.jpeg\" alt=\"\" width=\"228\" height=\"232\" srcset=\"https:\/\/phys-edu.net\/wp\/wp-content\/uploads\/2020\/03\/\u30b9\u30af\u30ea\u30fc\u30f3\u30b7\u30e7\u30c3\u30c8-2026-05-07-4.24.23.jpeg 476w, https:\/\/phys-edu.net\/wp\/wp-content\/uploads\/2020\/03\/\u30b9\u30af\u30ea\u30fc\u30f3\u30b7\u30e7\u30c3\u30c8-2026-05-07-4.24.23-295x300.jpeg 295w\" sizes=\"auto, (max-width: 228px) 100vw, 228px\" \/> <\/p>\n<p style=\"text-align: center;\"><a href=\"https:\/\/amzn.to\/48Jbe5f\">BeeSpi V (Simple Speed Measuring Device)<\/a><\/p>\n<p>You can get one for around 3,000 yen, and science versions can measure speed not only in km\/h but also in m\/s (meters per second), which is very useful. It\u2019s often used in experiments like building roller coasters to study potential and kinetic energy. Even more impressively, if you use two BeeSpi devices, you can measure acceleration.<\/p>\n<p>That means you can actually calculate the famous \u201cacceleration due to gravity\u201d yourself!<\/p>\n<p><iframe loading=\"lazy\" title=\"\u30d3\u30fc\u30b9\u30d4\uff12\u53f0\u3067\u91cd\u529b\u52a0\u901f\u5ea6\u3092\u6e2c\u5b9a\uff01\u3010\u79d1\u5b66\u306e\u30cd\u30bf\u5e33\u3011\" width=\"1140\" height=\"641\" src=\"https:\/\/www.youtube.com\/embed\/GF5rWpcLxiI?feature=oembed\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" referrerpolicy=\"strict-origin-when-cross-origin\" allowfullscreen><\/iframe><\/p>\n<p>This experiment is easy enough to try at home, so give it a go with your kids. You\u2019ll be amazed to see that both light and heavy objects experience the same acceleration.<\/p>\n<h3>What You\u2019ll Need<\/h3>\n<p>Here\u2019s what to prepare:<\/p>\n<p>Two BeeSpi devices, a stand, clips for the stand, a measuring tape, a mat (or even a paper cup), and beads or marbles.<\/p>\n<p>These are common science experiment tools, but as long as you can secure the BeeSpi devices, you can improvise. The mat can be something simple like a cut piece from a 100-yen shop item. A paper cup works just fine too.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-24748 aligncenter\" src=\"https:\/\/phys-edu.net\/wp\/wp-content\/uploads\/2016\/04\/6d49a6e3bc8b6b2a7a81c6d6b899b3e1.jpg\" alt=\"\u30b9\u30af\u30ea\u30fc\u30f3\u30b7\u30e7\u30c3\u30c8 2016-04-16 5.26.02\" width=\"215\" height=\"171\" srcset=\"https:\/\/phys-edu.net\/wp\/wp-content\/uploads\/2016\/04\/6d49a6e3bc8b6b2a7a81c6d6b899b3e1.jpg 447w, https:\/\/phys-edu.net\/wp\/wp-content\/uploads\/2016\/04\/6d49a6e3bc8b6b2a7a81c6d6b899b3e1-300x238.jpg 300w\" sizes=\"auto, (max-width: 215px) 100vw, 215px\" \/> <\/p>\n<h3>Procedure<\/h3>\n<p>\u2460 Attach the two BeeSpi devices to a stand and place a mat (or paper cup) underneath.<br \/>\n<img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-31477 aligncenter\" src=\"https:\/\/phys-edu.net\/wp\/wp-content\/uploads\/2018\/05\/df07526fd281a9622afd02d0e43e294a.png\" alt=\"\" width=\"280\" height=\"308\" srcset=\"https:\/\/phys-edu.net\/wp\/wp-content\/uploads\/2018\/05\/df07526fd281a9622afd02d0e43e294a.png 729w, https:\/\/phys-edu.net\/wp\/wp-content\/uploads\/2018\/05\/df07526fd281a9622afd02d0e43e294a-273x300.png 273w\" sizes=\"auto, (max-width: 280px) 100vw, 280px\" \/><\/p>\n<p>\u2461 Drop a marble and record the speeds measured by the upper and lower devices. If the marble hits the BeeSpi, try again.<br \/>\n<img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-24750 aligncenter\" src=\"https:\/\/phys-edu.net\/wp\/wp-content\/uploads\/2016\/04\/8545cf86a9365b848e6079cf5a3cd88e.jpg\" alt=\"\u30b9\u30af\u30ea\u30fc\u30f3\u30b7\u30e7\u30c3\u30c8 2016-04-16 5.26.21\" width=\"266\" height=\"487\" srcset=\"https:\/\/phys-edu.net\/wp\/wp-content\/uploads\/2016\/04\/8545cf86a9365b848e6079cf5a3cd88e.jpg 347w, https:\/\/phys-edu.net\/wp\/wp-content\/uploads\/2016\/04\/8545cf86a9365b848e6079cf5a3cd88e-164x300.jpg 164w\" sizes=\"auto, (max-width: 266px) 100vw, 266px\" \/><\/p>\n<p>\u2462 Once successful, measure the distance between the two BeeSpi devices using a ruler or measuring tape.<\/p>\n<p style=\"text-align: center;\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-24749\" style=\"line-height: 1.8em;\" src=\"https:\/\/phys-edu.net\/wp\/wp-content\/uploads\/2016\/04\/5ae37570261c9a3150c8fa0d4d2bda17.jpg\" alt=\"\u30b9\u30af\u30ea\u30fc\u30f3\u30b7\u30e7\u30c3\u30c8 2016-04-16 5.26.11\" width=\"242\" height=\"468\" srcset=\"https:\/\/phys-edu.net\/wp\/wp-content\/uploads\/2016\/04\/5ae37570261c9a3150c8fa0d4d2bda17.jpg 327w, https:\/\/phys-edu.net\/wp\/wp-content\/uploads\/2016\/04\/5ae37570261c9a3150c8fa0d4d2bda17-155x300.jpg 155w\" sizes=\"auto, (max-width: 242px) 100vw, 242px\" \/><\/p>\n<p>\u2463 Take the two recorded speeds (V\u2080 and V) and the distance (x), and plug them into the equation of uniformly accelerated motion:<br \/>\nV\u00b2 \u2212 V\u2080\u00b2 = 2ax<br \/>\nThen calculate the acceleration a using a calculator. (We\u2019ll explain the principle shortly.)<\/p>\n<h3>Example Results<\/h3>\n<p style=\"text-align: center;\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-31471\" src=\"https:\/\/phys-edu.net\/wp\/wp-content\/uploads\/2017\/03\/8efd4d5d2b33791591924b890550f23a.png\" alt=\"\" width=\"470\" height=\"216\" srcset=\"https:\/\/phys-edu.net\/wp\/wp-content\/uploads\/2017\/03\/8efd4d5d2b33791591924b890550f23a.png 800w, https:\/\/phys-edu.net\/wp\/wp-content\/uploads\/2017\/03\/8efd4d5d2b33791591924b890550f23a-300x138.png 300w, https:\/\/phys-edu.net\/wp\/wp-content\/uploads\/2017\/03\/8efd4d5d2b33791591924b890550f23a-768x353.png 768w\" sizes=\"auto, (max-width: 470px) 100vw, 470px\" \/><\/p>\n<p style=\"text-align: center;\">Sample results<\/p>\n<h3>The Principle: Why Can We Calculate Gravity?<\/h3>\n<p>Let\u2019s look at the theory behind measuring gravitational acceleration with a simple speedometer.<\/p>\n<p>By eliminating time t from two equations of uniformly accelerated motion (the velocity equation and the position equation), we obtain the following:<\/p>\n<p>x \u2212 x\u2080 represents the distance traveled.<\/p>\n<p>From this equation, if you measure v, v\u2080, x, and x\u2080, you can determine the acceleration a between those two points. Since falling motion is uniformly accelerated, measuring speed at just two positions allows you to calculate gravitational acceleration.<\/p>\n<p>For example, drop a ball five times from a height of 60.0 cm and measure its speed at 40.0 cm and 20.0 cm. Here\u2019s an example from an actual experiment:<\/p>\n<p>Height [m] Speed [m\/s] (average of 5 trials)<br \/>\n0.400 1.93<br \/>\n0.200 2.74<\/p>\n<p>Plugging these values into the formula gives 9.46 m\/s\u00b2 \u2014 very close to the theoretical value of 9.8 m\/s\u00b2. Try calculating it with your own data!<\/p>\n<h3>What is Uniformly Accelerated Motion?<\/h3>\n<p>The formula used here is one of the equations of uniformly accelerated motion. This type of motion refers to movement in a straight line where acceleration (the rate of change of speed) remains constant.<\/p>\n<p>Free fall is a classic example. Ignoring air resistance, objects accelerate downward at about 9.8 m\/s\u00b2 every second.<\/p>\n<h3>The Fascinating World of Gravity<\/h3>\n<p>In this experiment, we used marbles, but try using objects with different weights, like beads. You\u2019ll find that the acceleration remains nearly the same, close to 9.8 m\/s\u00b2. That\u2019s the beauty of gravitational acceleration.<\/p>\n<p>This fact was discovered over 400 years ago by Galileo Galilei. His finding that \u201cheavy and light objects fall at the same rate\u201d overturned common belief at the time and eventually led to Newton\u2019s law of universal gravitation.<\/p>\n<p>Interestingly, gravitational acceleration varies slightly depending on where you are on Earth. It\u2019s a bit stronger at the poles than at the equator. That\u2019s why rocket launch sites are built as close to the equator as possible \u2014 even a small difference in gravity can affect launch efficiency.<\/p>\n<p>On other celestial bodies, gravity is completely different. On the Moon, for example, it\u2019s only about 1.6 m\/s\u00b2 \u2014 roughly one-sixth of Earth\u2019s gravity. That\u2019s why astronauts can bounce so lightly there.<\/p>\n<p>Even something as simple as gravity connects to the shape of our planet and the vastness of space. That\u2019s where the true wonder of science lies. Try changing the drop height or the objects you use, and see what happens!<\/p>\n<h3>Contact &#038; Requests<\/h3>\n<p>Let\u2019s bring the wonders of science closer to everyday life! I share fun, easy-to-follow experiments you can try at home, along with helpful tips. Feel free to explore more!<\/p>\n<p>\u30fbThe content from this blog is now available as a book. Learn more here<br \/>\n\u30fbAbout the author, Ken Kuwako<br \/>\n\u30fbFor inquiries (writing, lectures, workshops, TV supervision, appearances, etc.)<br \/>\n\u30fbStay updated on new articles via X<\/p>\n<p style=\"text-align: center;\"><a href=\"https:\/\/www.youtube.com\/user\/kkuwako\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-35048\" src=\"https:\/\/phys-edu.net\/wp\/wp-content\/uploads\/2020\/03\/3d9640dad7bc5538e76f92da1966ee19.jpg\" alt=\"\" width=\"30\" height=\"21\" \/><\/a><a href=\"https:\/\/www.youtube.com\/user\/kkuwako?sub_confirmation=1\">Science Idea Channel<\/a> features experiment videos!<\/p>\n<h3>\uff15\u6708\u306e\u30a4\u30c1\u30aa\u30b7\u5b9f\u9a13\uff01<\/h3>\r\n<p>\u30ad\u30fc\u30f3\u3068\u51b7\u3048\u308b\u30c9\u30e9\u30a4\u30a2\u30a4\u30b9\uff01\u6c17\u6e29\u304c\u4e0a\u304c\u3063\u3066\u304f\u308b\u3053\u306e\u6642\u671f\u30fb\u30c9\u30e9\u30a4\u30a2\u30a4\u30b9\u3092\u4f7f\u3063\u305f\u6607\u83ef\u30fb\u51dd\u7d50\u30fb\u7b49\u901f\u5ea6\u76f4\u7dda\u904b\u52d5\u306e\u5b9f\u9a13\u306f\u3044\u304b\u304c\uff1f<\/p>\r\n<p><img class=\"alignnone wp-image-39516 aligncenter\" src=\"https:\/\/phys-edu.net\/wp\/wp-content\/uploads\/2022\/03\/0618612becc032a60bdda50090ccccbe.jpg\" sizes=\"auto, (max-width: 550px) 100vw, 550px\" srcset=\"https:\/\/phys-edu.net\/wp\/wp-content\/uploads\/2022\/03\/0618612becc032a60bdda50090ccccbe.jpg 1406w, https:\/\/phys-edu.net\/wp\/wp-content\/uploads\/2022\/03\/0618612becc032a60bdda50090ccccbe-300x168.jpg 300w, https:\/\/phys-edu.net\/wp\/wp-content\/uploads\/2022\/03\/0618612becc032a60bdda50090ccccbe-1024x572.jpg 1024w, https:\/\/phys-edu.net\/wp\/wp-content\/uploads\/2022\/03\/0618612becc032a60bdda50090ccccbe-768x429.jpg 768w, https:\/\/phys-edu.net\/wp\/wp-content\/uploads\/2022\/03\/0618612becc032a60bdda50090ccccbe-320x180.jpg 320w\" alt=\"\" width=\"453\" height=\"253\" \/><\/p>\r\n<p style=\"text-align: center;\"><a href=\"https:\/\/phys-edu.net\/wp\/?p=39513\">\u6db2\u4f53\u30bc\u30ed\uff01\u30c9\u30e9\u30a4\u30a2\u30a4\u30b9\u304c\u6d88\u3048\u308b\u307e\u3067\u306e\uff13\u6642\u9593\u3092\u79d1\u5b66\u3059\u308b\uff08\u6607\u83ef\u30fb\u51dd\u7d50\u30fb\u7b49\u901f\u5ea6\u76f4\u7dda\u904b\u52d5\uff09<\/a><\/p>\r\n<h3 style=\"text-align: left;\"><span style=\"font-size: medium;\"><b><strong>\u30c6\u30ec\u30d3\u756a\u7d44\u76e3\u4fee\u30fb\u30a4\u30d9\u30f3\u30c8\u7b49\u306e\u304a\u77e5\u3089\u305b<\/strong><\/b><\/span><\/h3>\r\n<ul>\r\n<li>4\u670830\u65e5\uff08\u6728\uff09\u300cTHE\u7a81\u7834\u30d5\u30a1\u30a4\u30eb\u300d\uff08\u65e5\u672c\u30c6\u30ec\u30d3\uff09\u306e<a href=\"https:\/\/phys-edu.net\/wp\/?p=62906\">\u79d1\u5b66\u76e3\u4fee\u3092\u62c5\u5f53\u3057\u307e\u3057\u305f<\/a>\u3002<\/li>\r\n<li>5\u67088\u65e5\uff08\u91d1\uff09<a href=\"https:\/\/phys-edu.net\/wp\/?p=62629\">\u7406\u79d1\u6559\u80b2\u30cb\u30e5\u30fc\u30b9<\/a>\u3092\u62c5\u5f53\u3057\u307e\u3057\u305f\u3002<\/li>\r\n<li>6\u670814\u65e5\uff08\u65e5\uff09\u3000\u5343\u8449\u5927\u5b66\u30a4\u30f3\u30b9\u30bf\u30ec\u30fc\u30b7\u30e7\u30f3\u300c\u63a2\u7a76\u300d\u306b\u3066\u8b1b\u5e2b\u3092\u52d9\u3081\u307e\u3059<\/li>\r\n<li>6\u670826\u65e5\uff08\u91d1\uff09\u3000\u5343\u8449\u5927\u5b66\u306e\u516c\u958b\u7814\u7a76\u4f1a\uff08\u4e2d\u5b66\u7406\u79d1\u306b\u3064\u3044\u3066\u6388\u696d\u516c\u958b\u4e88\u5b9a\uff09<\/li>\r\n<li>7\u670818\u65e5\uff08\u571f\uff09\u3000<a href=\"https:\/\/phys-edu.net\/wp\/?p=60018\">\u6559\u54e1\u5411\u3051\u5b9f\u9a13\u8b1b\u7fd2\u4f1a\u300c\u30ca\u30ea\u30ab\u30ab\u30b5\u30a4\u30a8\u30f3\u30b9\u30a2\u30ab\u30c7\u30df\u30fc\u300d\u306e\u8b1b\u5e2b\u3092\u3057\u307e\u3059<\/a>\u3002\u304a\u4f1a\u3044\u3057\u307e\u3057\u3087\u3046\u3002<\/li>\r\n<\/ul>\r\n<h3><b>\u66f8\u7c4d<strong>\u306e\u304a\u77e5\u3089\u305b<\/strong><\/b><\/h3>\r\n<ul>\r\n<li>\u300e\u5927\u4eba\u306e\u305f\u3081\u306e\u9ad8\u6821\u7269\u7406\u5fa9\u7fd2\u5e33\u300f\uff08\u8b1b\u8ac7\u793e\uff09\u2026\u4e00\u822c\u5411\u3051\u306b\u65e5\u5e38\u306e\u7269\u7406\u306b\u3064\u3044\u3066\u516c\u5f0f\u3092\u5143\u306b\u7d10\u89e3\u304d\u307e\u3057\u305f\u3002<a href=\"https:\/\/phys-edu.net\/wp\/?p=1827\">\u7279\u8a2d\u30b5\u30a4\u30c8<\/a>\u3067\u306f\u5b9f\u9a13\u3092\u591a\u6570\u7d39\u4ecb\u3057\u3066\u3044\u307e\u3059\u3002<strong>\u203b\u5897\u5237\u304c\u304b\u304b\u308a\uff16\u5237\u3068\u306a\u308a\u307e\u3057\u305f\uff082026\/02\/01\uff09<br \/><img class=\"alignnone wp-image-10940 aligncenter\" src=\"https:\/\/phys-edu.net\/wp\/wp-content\/uploads\/2013\/12\/0811159a99f69eeff1a357e3daed84e0-300x262.jpg\" sizes=\"(max-width: 220px) 100vw, 220px\" srcset=\"https:\/\/phys-edu.net\/wp\/wp-content\/uploads\/2013\/12\/0811159a99f69eeff1a357e3daed84e0-300x262.jpg 300w, https:\/\/phys-edu.net\/wp\/wp-content\/uploads\/2013\/12\/0811159a99f69eeff1a357e3daed84e0.jpg 311w\" alt=\"\u30b9\u30af\u30ea\u30fc\u30f3\u30b7\u30e7\u30c3\u30c8 2014-07-05 0.43.51\" width=\"220\" height=\"192\" \/><br \/><\/strong><\/li>\r\n<li>\u300e\u304d\u3081\u308b!\u5171\u901a\u30c6\u30b9\u30c8 \u7269\u7406\u57fa\u790e \u6539\u8a02\u7248\u300f\uff08\u5b66\u7814\uff09\u2026\u3000\u9ad8\u6821\u7269\u7406\u306e\u53c2\u8003\u66f8\u3067\u3059\u3002\u30a4\u30e9\u30b9\u30c8\u3092\u591a\u304f\u3057\u3066\u30a4\u30e1\u30fc\u30b8\u304c\u6301\u3066\u308b\u3088\u3046\u306b\u63cf\u304d\u307e\u3057\u305f\u3002\u6388\u696d\u306b\u3064\u3044\u3066\u3044\u3051\u306a\u3044\u3001\u7269\u7406\u304c\u82e6\u624b\u3001\u305d\u3093\u306a\u751f\u5f92\u306b\u304a\u3059\u3059\u3081\u3067\u3059\u3002<a href=\"https:\/\/phys-edu.net\/wp\/?p=45322\">\u7279\u8a2d\u30b5\u30a4\u30c8<\/a>\u306f\u3053\u3061\u3089\u3002<br \/><img class=\"alignnone wp-image-45718 aligncenter\" src=\"https:\/\/phys-edu.net\/wp\/wp-content\/uploads\/2024\/04\/dc1da64a8c8d1422062b4867c0607a1c.jpg\" sizes=\"(max-width: 184px) 100vw, 184px\" srcset=\"https:\/\/phys-edu.net\/wp\/wp-content\/uploads\/2024\/04\/dc1da64a8c8d1422062b4867c0607a1c.jpg 756w, https:\/\/phys-edu.net\/wp\/wp-content\/uploads\/2024\/04\/dc1da64a8c8d1422062b4867c0607a1c-300x269.jpg 300w\" alt=\"\" width=\"184\" height=\"165\" \/><\/li>\r\n<\/ul>\r\n<h3><span style=\"text-align: center;\">\u5404\u7a2eSNS\uff08\u66f4\u65b0\u60c5\u5831\u3092\u304a\u5c4a\u3051\uff01\uff09<\/span><\/h3>\r\n<p style=\"text-align: center;\"><a style=\"text-align: center;\" href=\"https:\/\/twitter.com\/kuwako\">X(Twitter)<\/a><span style=\"text-align: center;\">\uff0f<\/span><a style=\"text-align: center;\" href=\"https:\/\/www.instagram.com\/science_seeds\/\">instagram<\/a><span style=\"text-align: center;\">\uff0f<\/span><a style=\"text-align: center;\" href=\"https:\/\/www.facebook.com\/kuwakolab\/\">Facebook<\/a>\uff08\u65e5\u672c\u8a9e\uff09<\/p>\r\n<p style=\"text-align: center;\"><a style=\"text-align: center;\" href=\"https:\/\/bsky.app\/profile\/kagakunoneta.bsky.social\">BlueSky<\/a><span style=\"text-align: center;\">\uff0f<\/span><a style=\"text-align: center;\" href=\"https:\/\/www.threads.net\/@science_seeds?hl=ja\">Threads<\/a>\uff08\u82f1\u8a9e\uff09<\/p>\r\n<h3 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href=\"http:\/\/phys-edu.net\/wp\/?page_id=37\">About<\/a>\u00a0\u2026\u300c\u79d1\u5b66\u306e\u30cd\u30bf\u5e33\u300d\u306e\u30b3\u30f3\u30bb\u30d7\u30c8\u3084\u3001\u904b\u55b6\u8005\u3067\u3042\u308b\u6851\u5b50\u7814\u306e\u30d7\u30ed\u30d5\u30a3\u30fc\u30eb\u30fb\u60f3\u3044\u3092\u307e\u3068\u3081\u3066\u3044\u307e\u3059\u3002<\/li>\r\n<li><a href=\"https:\/\/phys-edu.net\/wp\/?page_id=188\">\u304a\u554f\u3044\u5408\u308f\u305b<\/a> \u2026\u5b9f\u9a13\u6559\u5ba4\u306e\u3054\u4f9d\u983c\u3001\u57f7\u7b46\u30fb\u8b1b\u6f14\u306e\u76f8\u8ac7\u3001\u79d1\u5b66\u76e3\u4fee\u7b49\u306f\u3053\u3061\u3089\u306e\u30d5\u30a9\u30fc\u30e0\u304b\u3089\u304a\u5bc4\u305b\u304f\u3060\u3055\u3044\u3002<\/li>\r\n<\/ul>\r\n","protected":false},"excerpt":{"rendered":"<p>I\u2019m Ken Kuwako, your science trainer. Every day is an experiment. \u201cIf you drop two objects with different weig [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":31477,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_sitemap_exclude":false,"_sitemap_priority":"","_sitemap_frequency":"","sns_share_botton_hide":"","vkExUnit_sns_title":"","vkexunit_cta_each_option":"","_lightning_design_setting":{"layout":"default"},"footnotes":""},"categories":[781],"tags":[],"class_list":["post-63141","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-science-en"],"jetpack_featured_media_url":"https:\/\/phys-edu.net\/wp\/wp-content\/uploads\/2018\/05\/df07526fd281a9622afd02d0e43e294a.png","jetpack-related-posts":[{"id":62239,"url":"https:\/\/phys-edu.net\/wp\/?p=62239&lang=en","url_meta":{"origin":63141,"position":0},"title":"Unlock the Magic with a Transparent Tube? See the Law of Energy Conservation in Action! (Also Great for Measuring Gravity!)","author":"\u6851\u5b50 \u7814","date":"2026\u5e744\u670810\u65e5","format":false,"excerpt":"I\u2019m Ken Kuwako, your Science Trainer. Every day is\u2026","rel":"","context":"Science","block_context":{"text":"Science","link":"https:\/\/phys-edu.net\/wp\/?cat=781&lang=en"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/phys-edu.net\/wp\/wp-content\/uploads\/2019\/10\/b996698d56c3ca1ac4e35f8b92249486.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/phys-edu.net\/wp\/wp-content\/uploads\/2019\/10\/b996698d56c3ca1ac4e35f8b92249486.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/phys-edu.net\/wp\/wp-content\/uploads\/2019\/10\/b996698d56c3ca1ac4e35f8b92249486.jpg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/phys-edu.net\/wp\/wp-content\/uploads\/2019\/10\/b996698d56c3ca1ac4e35f8b92249486.jpg?resize=700%2C400&ssl=1 2x"},"classes":[]},{"id":61938,"url":"https:\/\/phys-edu.net\/wp\/?p=61938&lang=en","url_meta":{"origin":63141,"position":1},"title":"Smash Together\u2014Half the Speed? Exploring Momentum with Colliding Carts!","author":"\u6851\u5b50 \u7814","date":"2026\u5e743\u670829\u65e5","format":false,"excerpt":"I'm Ken Kuwako, your Science Trainer. Every day is\u2026","rel":"","context":"Science","block_context":{"text":"Science","link":"https:\/\/phys-edu.net\/wp\/?cat=781&lang=en"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/phys-edu.net\/wp\/wp-content\/uploads\/2019\/06\/IMG_0787.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/phys-edu.net\/wp\/wp-content\/uploads\/2019\/06\/IMG_0787.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/phys-edu.net\/wp\/wp-content\/uploads\/2019\/06\/IMG_0787.jpg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/phys-edu.net\/wp\/wp-content\/uploads\/2019\/06\/IMG_0787.jpg?resize=700%2C400&ssl=1 2x"},"classes":[]},{"id":53396,"url":"https:\/\/phys-edu.net\/wp\/?p=53396&lang=en","url_meta":{"origin":63141,"position":2},"title":"Unlock the Mystery with Marbles! 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Every day is\u2026","rel":"","context":"Science","block_context":{"text":"Science","link":"https:\/\/phys-edu.net\/wp\/?cat=781&lang=en"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/phys-edu.net\/wp\/wp-content\/uploads\/2023\/01\/6541c95bc29ed89979ea1a2b9398b8f1.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/phys-edu.net\/wp\/wp-content\/uploads\/2023\/01\/6541c95bc29ed89979ea1a2b9398b8f1.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/phys-edu.net\/wp\/wp-content\/uploads\/2023\/01\/6541c95bc29ed89979ea1a2b9398b8f1.jpg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/phys-edu.net\/wp\/wp-content\/uploads\/2023\/01\/6541c95bc29ed89979ea1a2b9398b8f1.jpg?resize=700%2C400&ssl=1 2x"},"classes":[]},{"id":56349,"url":"https:\/\/phys-edu.net\/wp\/?p=56349&lang=en","url_meta":{"origin":63141,"position":3},"title":"The Physics of Fables: Graphing the Tortoise and the Hare&#8217;s Hidden Science","author":"\u6851\u5b50 \u7814","date":"2025\u5e7411\u670826\u65e5","format":false,"excerpt":"I'm Ken Kuwako, your Science Trainer. 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