Margaret Thatcher was chemist who graduated from Oxford before she became a lawyer and a politician. During her Chemistry endeavors she was known to have invented Mr. Whippy soft scoop ice cream at J. Lyons and Co.
Ice cream and milk in general has interesting surface tension properties. In general ice cream is a colloidal dispersion. Colloidal dispersion consists of small particles of one phase (solid, liquid or gas) in another continuous phase. The particle size may range from an order of nanometers to microns. The surface properties of the different phases can influence the properties as a whole. A typical ice cream is 30% ice, 50% air, 5% fat and 15 % matrix (a sugar solution) by volume. In this colloid suspension it is an emulsion, ice crystals and foam.
The interfaces between the two immiscible liquids in ice cream create in interfacial tension which is dependant on the surface area of the droplets. One interesting thing that early ice cream manufacturers did was shake the ice cream. This added air and the emulsion at the top was suspended in a foam. Margaret Thatcher, the Iron Lady, used her chemistry skills add more air to this emulsion. This created a lighter fluffier ice cream that cost less because air costs nothing.