• 1 · Religion and Magic
• 2 · Nature
• 3 · Human Being, Man in General
• 4 · Society, Civilization, Culture
• 5 · Abstract Ideas and Concepts
• 6 · History
• 7 · Bible
• 8 · Literature
• 9 · Classical Mythology and Ancient History

• Top
• 2 · Nature
• 22 · natural phenomena
• 22A · matter
• 22A3 · physical phenomena

22A31 · states of matter

• 22A311 · solid (state of matter)
• 22A312 · liquid (state of matter)
• 22A313 · gas (state of matter)