If you've eaten in a very high-end restaurant and have been served a dish with "foam" or a vegetable that has been transformed into little spheres then you have experienced molecular gastronomy. Simply put it combines the culinary arts with science.
Some of the various techniques include: spherification, carbonation, reverse, emulsification, gelification, foaming, and aeration. You can read more about these techniques.
For those who would like to experiment at home, a Spanish company called Texturas, produces a product line of kits and individual ingredients used to produce culinary specialties using the principals of molecular gastronomy. There are other manufacturers as well. You can purchase kits online at Amazon.com: Molecular Gastronomy "Made Easy".
This is a list of some of the ingredients used in molecular gastronomy:
Agar - a gelling agent extracted from red algae. This product has been used in Japan dating back to the 15th century. Agar is a source of fiber and is used to form gels or to make hot gelatins.