Why do I have to turn my iron on?

[x-ray_vision]

What is it about heat that gets rid of the wrinkles?

[Q.E.D]

Heat can also make wrinkles, e.g. a curling iron. I think the heat allows the fibers to set in whatever configuration they are in at the time, and since the iron and board are both flat, the fabric sets flat too.

[x-ray_vision]

but why?

[Pencil_Pusher]

From How stuff works

The same steam vapors are used to remove wrinkles from the clothes. The kits operate under the same principle as steam irons. When you press clothes on an ironing board, the steam carries its heat through the fabric. The combination of the water molecules and the heat temporarily breaks weak attractions between the fibers. This unlocks the fibers from the wrinkled state they have been in, and you can then press the fabric flat with the iron. The kits are slightly different, because you don’t have the weight and additional heat of the iron to press wrinkles out. The home dry cleaning kits rely on gravity to help wrinkles “fall out” from your clothes once you’ve removed them from the dryer and hung them up. This is why the kits emphasize getting your garments out of the dryer as soon as it clicks off. Outside the dryer, the clothes quickly cool down, and the fibers become less pliant. So, given the limited window of opportunity for gravity to do its job while clothes are still hot, clothing that is heavily wrinkled will most likely still be wrinkled after home dry cleaning. The FreshCare kit even advises you to launder dress shirts professionally, given their propensity to wrinkle.

[x-ray_vision]

But you can iron out wrinkles without water or steam.

[lorinada]

Not very well.

[x-ray_vision]

sure you can