Demonstrate how supply and demand determine the price and quantity exchanged of goods and services.

On September 6, 2007, the Des Moines Register's Business Section featured the article Wine Lovers have such fun, they pay to help harvest grapes. The article noted the number of wineries in Iowa increased significantly during the 1990s. It also discussed how Summerset Winery uses volunteers to harvest some of their grapes. The volunteers pay $20.00 for the experience of harvesting grapes. They also receive a meal, a t-shirt, and the opportunity to stomp some grapes (that's the fun part)

Now let's analyze the determinants of demand that explain this increase in the demand for stomping graph and for wine. Our course textbook lists five reasons why the demand might change (why the demand curve might shift) including: (1) income; (2) tastes and preferences; (3) number of buyer; (4) expectations; and (5) income

Which determinants of demand might account for this increased interest in stomping grapes and drinking wine?