Concrete is the most common artificial composite material of all and typically consists of loose stones (aggregate) held with a matrix of cement. Concrete is a very robust material, much more robust than cement, and will not compress or shatter even under quite a large compressive force.
2) Y-axis contains absolute brightness Why do astronomers use the H-R Diagram? Astronomers use H-R Diagrams to classify stars and to understand how stars change over time.
Horizontal or X-Axis: The horizontal or X-axis shows you the scale ofvalues into which the measurements fit. These measurements are generallygrouped into intervals to help you summarize large data sets. Individual datapoints are not displayed.3. Bars: The bars have two important characteristicsâheight and width.