Final answer:
When determining physical count to determine quantity, ensure the count isn't disrupted and account for irregularities. Exact counts are possible with direct counting, but measurements like liquid volume involve some uncertainty and require careful reading techniques.
Step-by-step explanation:
When determining physical count to determine quantity, two important things to watch for are ensuring that the number of objects being counted does not change during the counting process and accounting for any irregularities in the object being measured. Counting provides an exact number of the quantity, such as the number of eggs in a carton. However, when measuring quantities that cannot be directly counted, like the volume of a liquid in a graduated cylinder, the measurement can be uncertain. In such cases, it is essential to read at the bottom of the meniscus to improve measurement accuracy.