Pepper does not melt ice. Pepper is regarded as hot due to its spicy sensation in your mouth when consumed, but it does not have any real heat to it.
If you put enough black pepper on ice in sunlight the black pepper will absorb the heat from the sun and may transfer that heat to the ice causing it to melt.
Pepper, on its own, will not melt ice.
yes
yes
no pepper decreases the melt
You need to determine what you think will melt the fastest, and that will be your hypothesis. If you think that pepper will melt it faster, you would say "My hypothesis is that the pepper will melt ice faster than the other variables (sand, salt, and sugar)."
it all depends on the temperature. ice melts faster at higher temperatures
You need to determine what you think will melt the fastest, and that will be your hypothesis. If you think that pepper will melt it faster, you would say "My hypothesis is that the pepper will melt ice faster than the other variables (sand, salt, and sugar)."
boiling water
because it does!
yes it does, so will salt and probably pepper
Salt
Pepper would only melt ice in the presence of sunlight which would absorb into the pepper, warm up, and raise the temperature of the ice near to or touching the pepper. Coffee grounds, planting soil etc. would work the same way. On a larger size scale, tree trunks often have a hole around them where the snow has melted away, since the bark warms up in even feeble sunlight and radiates the heat into the snow. Salt, on the other hand, combines with the ice (water) to produce a solution with a lower freezing point. This would melt the ice without sunlight, as long as the temperature stays above the new freezing point.