How to Make a Homemade Water Gauge for Kids

Wash an empty two-liter soda bottle. Remove the bottle's label and clean away as much of the sticky residue as possible.

Cut the top of the soda bottle off at the point where the slope of the top meets the straight sides. Use the knife to cut the bottle, being careful to cut the bottle in a clean line so that both the top and the bottom portions of the bottle are usable.

Turn the upper portion of the bottle upside down and place it into bottom half of the bottle so that it creates a funnel.

Pour just enough water into the bottle so that only the "bumps" molded in the bottom are filled with water. Use the line from the water level in the bottle as the gauge's "point zero". Mark this point with a permanent marker and label it with a zero.

Line up the ruler at point zero and make a mark on the outside of the bottle at every quarter-inch or half-inch, depending on how accurate you want your measurements to be.

Give children craft paints or stickers to decorate their gauge, as desired. If using stickers, cover them with waterproof tape.