sweeping - Curling Basics - curling explained; excellent for beginners

The effect of sweeping:

reduces the friction between the "stone" and the ice surface, allowing the "stone" to maintain its momentum longer

smooths the "pebble" and removes frost and debris

causes the "pebble" to melt briefly, creating a thin film of moisture that acts as a lubricant between the "ice" and "stone"

the "stone" does not slow down as quickly, therefore it travels further

as a result of momentum being maintained by sweeping, the "stone" will arrive at that the target sooner. Since the amount the "stone" "curls" is dependant upon time, the "stone" will not have as much time to "curl" and will therefore travel straighter