Gallium highly reactive (rubidium and caesium) nor highly toxic (mercury) and can therefore be used in metal-in-glass high-temperature thermometers. It is also notable for having one of the largest liquid ranges for a metal, and for having (unlike mercury) a low vapor pressure at high temperatures. Gallium's boiling point, 2673 K, is more than eight times higher than its melting point on the absolute scale, the greatest ratio between melting point and boiling point of any element. Unlike mercury, liquid gallium metal wets glass and skin, along with most other materials (with the exceptions of quartz, graphite, and Teflon), making it
Problem-posing education Problem-posing education Problem-posing education is a term coined by Brazilian educator Paulo Freire in his 1970 book "Pedagogy of the Oppressed". Problem-posing refers to a method of teaching that emphasizes critical thinking for the purpose of liberation. Freire used problem-posing as an alternative to the banking model of education. Freire's pedagogy emerged from his observations and experiences working as an instructor in literacy programs with peasant laborers in Brazil. During this work, Freire became aware of the economic, political, and social domination resulting from paternalism. Paternalism leads to a culture of silence, which keeps people from confronting their oppression. He