What instrument is used to measure the depth or amount of fluid in a container?

The dip stick is specifically designed to measure the depth or amount of fluid in a container. It is a simple yet effective tool typically used in various contexts, such as checking engine oil levels in vehicles or measuring the fluid levels in tanks and reservoirs. The dip stick often features marked increments along its length, allowing for straightforward reading of fluid levels, which is crucial for ensuring proper fluid management and maintenance.

Other options, while they serve measurement purposes, do not specifically apply to measuring the depth of fluid in a container. For example, fluid gauges may indicate pressure or other fluid characteristics rather than depth, measuring cups are primarily utilized for precise volume measurements rather than depth, and clearance tools are designed to measure space or gaps rather than fluid levels. Therefore, the dip stick is the most suitable instrument for this specific purpose.