Black Friday: lifetime access is on a special offer in the app, until November 30. Black Friday: special offer on lifetime access, until November 30. Download
기체계를 사용하여 공기의 밀도를 측정할 수 있습니다.gichegye-reul sayonghayeo gong-ui mildeureul cheugjeonghal su itsseumnida.You can measure the density of air using an aerometer.