Brief description

A level is an instrument used to establish or verify a horizontal plane. It is essential in construction, carpentry, and masonry to ensure that surfaces are flat and structures are aligned with gravity.

Use / Function

• Primary use: Determining if a surface is horizontal (level) or vertical (plumb).
• Secondary uses: Transferring elevation points across a distance (water level).
• Scale: Domestic to Industrial.

Operating principle

• Water Level: Based on the principle that water in a connected system seeks its own level due to gravity. If a tube is filled with water, the surface at both ends will be at the same elevation, regardless of the tube’s shape.
• Spirit Level: Uses a bubble in a liquid-filled vial. The vial is slightly curved so that the bubble naturally seeks the highest point. When the bubble is centered between markings, the surface is level.

How to create it

Water Level (Simplest)

1. Materials: A long, clear flexible tube (hose) and water.
2. Assembly: Fill the hose with water, ensuring no air bubbles are trapped.
3. Use: Hold the ends up. The water level at one end matches the elevation of the water level at the other end.

Spirit Level

1. Materials: A small glass or plastic vial, alcohol (to prevent freezing and allow free movement), and a straight frame.
2. Assembly: Fill the vial leaving a small bubble. Seal it. Mount it precisely in a straight block of wood or metal.
3. Calibration: Place on a surface, mark the bubble’s position. Rotate 180 degrees. Adjust until the bubble is in the same position in both orientations.

• Technical level: Basic (Water Level) to Intermediate (Spirit Level).

Materials needed

• Essential: Clear tubing or a glass vial, liquid (water or alcohol).
• Tools: Saws and sandpaper for the frame.
• Substitutes: A plumb bob can be used to find vertical, and a square can then determine horizontal.

Variants and improvements

• A-Frame Level: A large “A” shape with a plumb bob hanging from the apex. When the plumb line aligns with a mark on the crossbar, the feet are level.
• Laser Level: Uses a laser beam to project a level line.
• Bullseye Level: A circular level for leveling planes in all directions at once.

Limits and risks

• Accuracy: Depends on the straightness of the frame and the precision of the vial mounting.
• Parallax: Reading the bubble from an angle can cause errors.
• Temperature: Extreme heat or cold can affect the bubble size or liquid viscosity.