Which method is better for keeping drinks cold in a picnic cooler water at 0 degree celsius or ice why?

While water at 0 degree celsius may seem like a viable option for keeping drinks cold given its freezing point water is not recommended for this purpose. Here's why:

Thermal Conductivity: Ice has a lower thermal conductivity compared to water. Thermal conductivity refers to the ability of a material to transfer heat. The lower the thermal conductivity the slower heat is transferred.

Therefore ice acts as a better insulator which helps in keeping the drinks colder for a longer duration.

Specific Heat Capacity: The specific heat capacity of a substance refers to the amount of heat required to raise the temperature of one unit mass of that substance by one degree celsius.

Ice has a higher specific heat capacity than water. This means that it takes more energy to raise the temperature of ice than water.

Hence, ice can absorb more heat without significantly melting keeping the drinks cooler.

Phase Transition: The phase transition of water from liquid to ice involves the release of latent heat. This means that as water freezes it releases energy in the form of heat.

This heat can help to keep the surroundings cool slowing down the warming process.

Melting Point: The melting point of ice is 0 degree celsius. As long as the temperature remains below freezing the ice will not melt. This ensures that the drinks remain colder for a more extended period.

Portability and Availability: Ice is more convenient to transport and handle compared to large volumes of water especially during outdoor activities like picnics.

Additionally ice cubes or crushed ice can easily conform to the shape of the cooler maximizing the surface area in contact with the drinks leading to better cooling.

In summary using ice is the better method for keeping drinks cold in a picnic cooler. Its low thermal conductivity high specific heat capacity latent heat release and melting point make it a more effective cooling agent compared to water at 0 degree celsius.