* Size: A boulder is significantly larger than a pebble. A boulder can be as large as a car, while a pebble is small enough to fit in your hand.
* Weight: Because of their size difference, a boulder is much heavier than a pebble. It would require more effort and strength to lift.
* Effort: Picking up a pebble is easy, requiring minimal effort. Picking up a boulder would require significant strength and possibly tools.
So, while both actions involve picking something up, the effort and the tools required make them completely different experiences.
