The Hydrogen bonds are broken and reformed
Any type of heat styling tool does damage to the hair. To help prevent damage I recommend you use a thermal hair protectant. Matrix Sleek Look has an awesome line in thermal styling products. I would also use a deep condition to help bring moisture back into your hair from the drying effects of heat styling tools.
lighting a match from a matchbox is a chemical change.
Ignition of a match is a chemical process.
The drying itself is (always) a physical change.
Drying is a physical process (because evaporation is a physical change), not a property.
physical
No, it is the same as drying the bottom of your hair.
Drying (involving only the water evaporation) is a physical change.
Yes.
In the natural unstretched state the hair is Alpha Keratin and when the hair has been styled in the unnatural state it is beta keratin. When blow drying for example the keratin in the alpha keratin is changed to beta keratin, causing the hair to temporarily in its new shape. Once the hair takes in moisture from the atmosphere or becomes wet, it reverts back to the normal state
Physical, it is still H2O
Physical. Because you can reverse it by drying it out.