Salt
It will certainly not keep the water in the bucket from freezing and, if the temperature goes low enough, the bottled salt water will also freeze.
Light a fire next to it.
Salt lowers the freezing temperature of water, which means that it has to be colder for the water to freeze.
It changes the freezing and boiling point.
It'll keep the dog from drinking it, but doubt it will help with freezing.
adding additives to water does effect the freezing point of water. When NaCl is added, it can effect it. Because the outside temperature isn't cold enough to keep the ice frozen inside.
Believe it or not, you can keep water protected in Antarctica by keeping it in a fridge. The temperature is so cold that a fridge could keep it safe from freezing.
Coolant container will say if it is pre-mixed or full strength. If full strenght, mix it 50/50 with water. Pre-mixed coolant can be added "as-is"
It is possible to keep water as liquid below its freezing point - see related link.
Because alcohol has a lower freezing point than water. By mixing it with water, you lower the waters freezing point. So it keeps the water from freezing on the windshield.
Sodium Chloride when added to water helps reduce the freezing temperature of water, meaning that water will stay liquid at temperatures below it's actual freezing point of 0 degrees Celsius. Similarly, when sodium chloride is added to ice, the temperature of the mixture reduces rapidly and helps keep things cooler and ice creams are best when they're cold :) Hope this helps.
In a location where the temperature does not fall below the freezing point (32 degrees Fahrenheit)