교양수업에서 상자안에 물건 넣고 흔들어서 맞추는 걸 하는데 교수님이 추리를 도와주는 도구를 가져오라고 하시더라구요 저는 저울밖에는 생각이 안나는데 안보이는걸 추측할수있게 도와주는 기발한 물건이 있을까요  밀도나 무게정도는 알수있을것같은데 어렵네요 ㅋㅋ