There is about one quart of cream in one gallon of whole milk. There is less cream in the lower fat content milk varieties.
You can, however, heavy cream is much thicker than whole milk which will cause the soup to be a much thicker consistency than you may want. Milk is a better choice.
"Half and half" is half milk and half cream. All the cream is taken from the milk and then a 1:1 ratio of fatless milk and cream are mixed. half and half has more fat than whole milk, so they are not interchangeable.
By volume: 10 gallons of whole milk will yield 1 gallon of cream. (http://www.milknmore.com/?name=aboutmilk&op=listNews&id=279&mid=476) Milk weighs approximately 8.6 lbs./gal. Cream weighs approximately 8.4 lbs./gal. If you really want to know how much cream is in a POUND of milk, you'll need to do the calculations yourself.
A traditional Italian artisan yellow base mix contains 1030g milk (3.5% fat), 300g sugar and 12 egg yolks (approx 200g). Total weight 1530g. When mixed, whipped and frozen the air added (called overrun) increases the volume by a factor of 1.5. So, 1.53Litres makes 2.3 litres of ice cream. Divide original ingredients weight by 1.5 to find amounts required to make 1 litre. ie 687 g milk, 200g sugar and 8 eggs (approx 120g). Use conversion factor of litres to US gallons (3.75 I believe) to find amounts you need.
In 1933, a gallon of whole milk cost around 44 cents on average.
The weight of a gallon of milk is only slightly greater than a gallon of water, about 3% more. A US gallon with 2% milkfat weighs about 8.4 pounds, compared to 8.6 pounds for "whole milk" and 8.35 pounds for a gallon of water. Milk is 87 % water, thus a gallon of milk will not differ from milk much. The 8.6 lbs/gal factor (whole milk) is correct. The weight increases as fat is removed. By weight: Milk : 8.6 lb/gallon Condensed milk : 9.4 lb/gallon Cream 8.28 lb/gallon * The British or Imperial Gallon is defined as exactly 10 pounds of water. You can convert the above figures by using 1 Imperial Gallon = 1.201 US gallons.
1.1
How much does a gallon of sour cream weigh
A gallon of milk cost $1.01 in 1958
8.6
A Gallon of regular milk costed about $1.15 in the year 1970.
Cream is separated from whole milk by centrifuge or gravity. If you have unhomogenised milk, leave some to stand in the fridge and remove the cream from the top of the container the next day. Milk that has been homogenised will not give much cream in this way. Raw milk would work well.