how to produce electric currents with magnets - part 3 of 17. experiments with a magnet and battery show that electricity and magnetism are interrelated and that an electric current can produce magnetic effects - 紙夾 個影片檔及 b 捲影像00:36電池
flowering plants and their parts - part 19 of 26. reviews the typical structure of the "higher" green plants and illustrates, through demonstrations, the functions and interdependence of their parts - 紙夾 個影片檔及 b 捲影像00:30
flowering plants and their parts - part 16 of 26. reviews the typical structure of the "higher" green plants and illustrates, through demonstrations, the functions and interdependence of their parts - 紙夾 個影片檔及 b 捲影像00:29
flowering plants and their parts - part 14 of 26. reviews the typical structure of the "higher" green plants and illustrates, through demonstrations, the functions and interdependence of their parts - 紙夾 個影片檔及 b 捲影像00:33
hand of a young woman writing in a bookkeeping diary entries in august on the table - 紙夾 個影片檔及 b 捲影像00:06
hand of a young woman writing in a bookkeeping diary entries in august on the table - 紙夾 個影片檔及 b 捲影像00:11
hand of a young woman writing in a bookkeeping diary entries in august on the table - 紙夾 個影片檔及 b 捲影像00:07
hand of a young woman writing in a bookkeeping diary entries in august on the table - 紙夾 個影片檔及 b 捲影像00:08
hand of a young woman writing in a bookkeeping diary entries in august on the table - 紙夾 個影片檔及 b 捲影像00:13
hand of a young woman writing in a bookkeeping diary entries in august on the table - 紙夾 個影片檔及 b 捲影像00:06
hand of a young woman writing in a bookkeeping diary entries in august on the table - 紙夾 個影片檔及 b 捲影像00:07
school supplies, color pencil, water color , tack ,paper clip with copyspace background - 紙夾 個影片檔及 b 捲影像00:14
school supplies, color pencil, water color , tack ,paper clip with copyspace background - 紙夾 個影片檔及 b 捲影像00:13
school supplies, color pencil, water color , tack ,paper clip with copyspace background - 紙夾 個影片檔及 b 捲影像00:16
cu, distressed man twisting paper clip and working on laptop, los angeles, california, usa - 紙夾 個影片檔及 b 捲影像01:02
cu, distressed man twisting paper clip and working on laptop, los angeles, california, usa - 紙夾 個影片檔及 b 捲影像00:14
