Any impurity decrease the freezing point of water.
20 - 25 seconds depends on the amount of sugar and ice :)
OBVIOUSLY.
Yes, it is correct.
record the temperature per minute as it melts
Possibly. The amount of surface area the ice cube has could influence how fast it gets warm, and then how fast it melts.
yes, in fact it does. in the sun, the heat will get to the ice cube faster than it would if it was, say, on te counter
Well it really depends on the quantity But i know for a fact that salt will dissolve it quicker than sugar
No, it wouldn't. a sugar cube would melt a lot faster in a cup of Hot water. the hot water helps it desolve more evenly than cold water.
The factors that affect how fast an ice cube melts in air include the temperature of the air, the humidity level, and any external sources of heat. Warmer temperatures and higher humidity levels will cause the ice cube to melt faster, while cooler temperatures and lower humidity levels will slow down the melting process.
Salt affects how fast ice melts in a cup of water. When you add salt, the melting process will be faster but it will only affect the part of the ice cube that comes into contact with salt.
Fire
In general, sugar does not affect the rate at which liquids melt. However, adding sugar to water, for example, can slightly lower the freezing point of the liquid, making it freeze at a slightly lower temperature.