The physical description for potions:
Physical Description: A typical potion or oil consists of 1 ounce of liquid held in a ceramic or glass vial fitted with a tight stopper. The stoppered container is usually no more than 1 inch wide and 2 inches high. The vial has AC 13, 1 hit point, hardness 1, and a break DC of 12.
…and that of scrolls:
Physical Description: A scroll is a heavy sheet of fine vellum or high-quality paper. An area about 8-1/2 inches wide and 11 inches long is sufficient to hold one spell. The sheet is reinforced at the top and bottom with strips of leather slightly longer than the sheet is wide. A scroll holding more than one spell has the same width (about 8-1/2 inches) but is an extra foot or so long for each additional spell. Scrolls that hold three or more spells are usually fitted with reinforcing rods at each end rather than simple strips of leather. A scroll has AC 9, 1 hit point, hardness 0, and a break DC of 8.
…mention nothing of the items' weight. The general information page for Magic Items states:
[…]When a weight figure is not given, the item has no weight worth noting (for purposes of determining how much of a load a character can carry).
Am I interpreting this correctly as potions and scrolls have no weight in a character's inventory?
Potions and scrolls have effectively no weight
In Pathfinder's antecedent Dungeons and Dragons 3.5, ink or potion vial (Player's Handbook 128) costs 1 gp and weighs 1/10 lb.1 However, Pathfinder eliminated vial bookkeeping. The DM may still have 16 potions weigh 1 lb. Ask before loading up.
Scrolls in both games possess negligible weight, but a DM may house rule penalties upon a scroll user without at least a scroll case who carries a scroll mountain (or, more likely, upon a scroll user who attempts to locate in the heat of battle a particular scroll from hundreds carried).
1 In D&D 3.5 the ink or potion vial description says, "A vial holds 1 ounce of liquid. The stoppered container usually is no more than 1 inch wide and 3 inches high" (ibid. and emphases mine). However, on Physical Description says
Pathfinder eliminates this contradiction by omitting dimensions from the vial so that only the physical description of potions and oils includes dimensions.