Magnetic braking demonstration

Magnetic braking demonstration with a hard disk drive and a neodymium magnet. It is not possible to stop completely the disk because the lower the speed the lower the pull.

Chill a Beverage Can Quickly. REUSABLE Method.

I have seen many times on the web and on Youtube how to chill a soft drink can or bottle quickly melting some ice with salt. This mixture is known as a cooling bath and is used in chemistry to get instant cooling or  a constant temperature.

But it is a mess to make all this in order to drink a can that we forgot outside the refrigerator so I propose this alternative method.

How to chill a can without using ice and without wasting salt. With this method we use salt as an antifreeze in a jar with salt water. You only have to keep the jar in the freezer and use when necessary. After that you can put the jar in the freezer again so you dont have to throw away the salt.

Curie Point or Curie Temperature demonstration

In this video we demonstrate how a piece of hot steel is not attracted by a magnet until it cools down to a point. This point is known as the Curie Point or Curie Temperature of that material. A heat-induced ferromagnetic-paramagnetic transition is used in magneto-optical storage media, for erasing and writing of new data. Famous examples include the Sony Minidisc format, as well as the now-obsolete CD-MO format.