The larger surface area of the spoon compared to the tines of a fork means that when a spoon is used for stirring, it moves a greater volume of liquid with each motion. The broader stirring action helps not just in moving the particles around but also in ensuring that sugar is not concentrated in one part of the liquid.
You can also test it yourself with a transparent liquid (green tea), a fork will cause the sugar to be stirred in place at the bottom.
The larger surface area of the spoon compared to the tines of a fork means that when a spoon is used for stirring, it moves a greater volume of liquid with each motion. The broader stirring action helps not just in moving the particles around but also in ensuring that sugar is not concentrated in one part of the liquid.
You can also test it yourself with a transparent liquid (green tea), a fork will cause the sugar to be stirred in place at the bottom.