伸縮 and 寸法: dimensions before and after stretching
Check the state in which the 寸法 of a stretching or retracting object was measured. Do not mix its unstretched and stretched lengths as measurements under identical conditions.
伸縮 describes stretching and retracting
伸縮, read しんしゅく, refers to stretching and contracting. この布は伸縮しやすく、模型にかぶせやすい。 says that this cloth stretches and contracts easily, making it easy to fit over the model.
伸縮しやすい describes a tendency to stretch and contract easily. It does not say that the cloth’s length always stays at the same numerical value.
Record 寸法 with the object’s state
寸法, read すんぽう, means dimensions. When a length is measured, check which part was measured and the state of the object.
Suppose the same cloth measures 20 centimeters before stretching and 25 centimeters while stretched. The conditions differ, so the two records are not necessarily contradictory.
Separate a mechanism from a measurement
棒が伸縮する仕組みを図で説明した。 says that someone used a diagram to explain the mechanism by which the rod extends and retracts. The sentence alone does not identify a state in which the actual rod’s length was measured.
Before comparing dimensions, check the measurement position and whether the object was extended or retracted. A description of 伸縮 as a property or mechanism is not itself a measured value.
If the cloth was 20 centimeters long before stretching, must it still be 20 centimeters long while stretched?
Show the answer and why
No. Its dimension may change when stretched. Check the measurement state when comparing 寸法.