Upon what does the strength of a substance depend?
The strength of a substance depends upon the amount of cohesion among its particles.
What effect does heat have upon the cohesion of bodies?
Heat tends to destroy the cohesion of bodies by separating their particles.
How does heat affect ice?
Heat destroys the cohesion between the particles of ice, and thus it is changed into water.
How does heat affect water?
When still more heat is applied, the cohesion in the water is destroyed, and thus it is changed into steam.
Is there any cohesion in steam?
No; there is not any cohesion in steam.