Here’s one that seems like it should be simple, but that I just don’t understand the underlying physics.
If I put my iron face down on the ironing board when it’s cold, it doesn’t slide well at all, and takes a good push to move it. But once it’s heated up, I can move it easily with just a light touch of a couple of fingers.
Why does the temperature seem to affect the amount of friction?
Assuming that you have the iron on the steam setting, it’s because the iron is gliding on a cushion of steam. So it is simple after all!
It’s a good question. I don’t think that the coefficient of friction between the steel and the fabric would vary much at all in that temperature range. Something else must be at work here.
If you look closely while you’re ironing, you will see a small “ripple” forming in the fabric near the edge of the iron, which propagates ahead of the iron as it moves back and forth. This means that the fabric underneath the iron is in tension (stretching), and it’s the heat plus the stretching that removes the wrinkles.
My guess is that this “ripple” can propagate more easily in the hot fabric, because the heat makes it more pliable.
Here are some possibilities.
When the iron and fabric are in contact, they form weak bonds with each other. When they are hotter, there is more energy available to break these bonds, so less force is required from you.
Perhaps these bonds are constantly forming and breaking and reforming. When the iron is hotter, a larger percentage of the bonds are broken at any given instant, so the cofefficient of friction is lower.
Both of the above.
Because, when powered, the ion reactor in the Iron’s core creates a neagtive sub-space force field that is constantly modulated at random frequencies. The force field allows minute clothing particulates to glide along the aeon flux wave generated by the nuclear particlulate reaction created as a result of the sub-space disturbance. Doesn’t anyone watch Star Trek anymore?:smack:
I actually think this is the best answer but with a slight modification. The clothing being ironed has the same amount of water vapor in it as the air. When the iron is hot and it makes contact with the clothing that water vapor becomes excited and acts as a buffer between the iron and the cloth creating a ‘steam cushion’ for the iron to glide on.
It would be interesting to see what happens with an iron used on cloth in a 0% humidity environment.