Which material kept soup hottest?

It's impossible to say definitively which material keeps soup hottest without more context. Here's why:

* Factors Beyond Material: The ability of a container to keep soup hot depends on several factors beyond just the material:

* Insulation: The thickness and type of insulation around the container are crucial.

* Lid: A tight-fitting lid significantly reduces heat loss.

* Initial Temperature: The hotter the soup is initially, the longer it will stay hot.

* Ambient Temperature: A colder environment will cause the soup to cool faster.

* Surface Area: A wider opening or a larger container will lose heat faster.

* Common Materials: Here are some popular materials used for soup containers and their general properties:

* Stainless Steel: Good conductor of heat, but can lose heat quickly. Often used in combination with insulation.

* Ceramic: Good insulator, especially when glazed. Can be heavy and prone to cracking.

* Plastic: Generally not the best choice for keeping food hot, as it can melt or leach chemicals.

* Glass: A good insulator, but can be fragile and prone to breaking.

* Vacuum Insulated: This type of container, often made of stainless steel, creates a vacuum between the walls to reduce heat transfer. This is the most effective at keeping things hot.

In Summary:

To truly determine the best material for keeping soup hottest, you need to consider the specific container design and the factors listed above. A vacuum insulated container is generally the most effective, but other materials like ceramic or insulated stainless steel can perform well too.