16 fluid ounces of water is a standard serving size that is about the size of a water bottle. You can easily visualize this amount as 2 cups of liquid.

In kitchen measures
2 cups
96 tsp · 32 tbsp · 2 cups
about the size of a water bottle
Water typically ranges 1–1 g/mL depending on how it's packed. A firmly packed scoop weighs more.