Video Below:
In the early 1900's, it was believed that ferromagnetic materials like iron, when placed in a coil of wire and subjected to a magnetic field, would orient the magnetic domains instantaneously. In 1919, Heinrich Barkhausen, while working in magnetism and acoustics, discovered that in fact, the orientation of the domains occurred in steps and in a discreet manner.
All ferromagnetic materials have domains that are, at the atomic level, are normally aligned in a straight line. When a magnetic field approaches, the domains align with the magnetic field.
This demonstration shows that effect and reproduces the results obtained by Barkhausen. If you need magnet wire to wind the coil for the experiment, Radio Shack has a three-pack of assorted gauges and lengths. But as you will see in the video, coil winding is not necessary. The links follow the video:

The first link is a MagLab discussion of the Barkhausen effect here. The second is an experiment with coil winding as I have done here. This link demonstrates the clicking sound better than I have but I am not sure why. Have fun with magnetism!

Video Below:
Determining the percent solids in either a water based or organic solvent based material is a basic procedure used to make calculations for reactions, and in some cases, just curiosity. But, in the world of chemistry, it is a fundamental process. Although I used Elmer's glue as an example, all solutions and emulsions with solid constituents are applicable. The video is really self explanatory but here is the breakdown of the method:

1. Weigh the aluminum cup. Label this A
   
2. Without taring, add the wet sample. Label this B
   
3. Let the sample evaporate or warm slowly to drive off the water or solvent. Label this C
   
4. Weigh the now dry sample and the cup.
   

Now, use this simple formula to calculate the solid content:
C - A
B - A
Do the subtraction and divide the result and multiply by 100. You now have the amount of solid chemical in the cup in percent.  Enjoy!