State
Solid
Energy
▮▯▯▯▯
Last change
—
Property
Solid
Liquid
Gas
Keeps its shape?
Yes
No
No
Fixed volume?
Yes
Yes
No
Easy to squash?
No
Barely
Yes
🔥 Add energy (heat)
❄ Remove energy (cool)
↺ Reset
Energy
in
climbs the ladder
solid → liquid → gas
. Energy
out
slides back down
gas → liquid → solid
.