Final answer:
Expansion affects distance measurements by causing distances between cosmic structures to increase over time due to cosmic expansion, and by causing physical materials to expand or contract with changes in temperature, leading to measurable distance changes.
Step-by-step explanation:
Expansion affects distance measurements in several ways, primarily in cosmology and thermal dynamics. In cosmological terms, due to the cosmic expansion, the universe experiences a uniform change in scale over time, represented by a scale factor R. When R increases, it means distances between cosmic structures, such as clusters of galaxies, also increase. For instance, if the scale factor R doubles, the distance between these clusters doubles as well, illustrating how cosmic distances grow due to expansion.
In the context of everyday materials, expansion also results from increases in temperature, affecting physical distances. For example, structures like the Eiffel Tower become taller, and gaps must be left between railroad rails to account for thermal expansion. The distance changes are calculated using coefficients of thermal expansion for the specific materials, which tell us how much they expand or contract with temperature changes. This reflects the broader fact that all materials are subject to physical changes in length due to temperature variances, leading to measurable differences in distance measurements over time or with varying thermal conditions.