Science ObjectDigital resources are stored online in your NSTA Library.
Science Objects are two hour on-line interactive inquiry-based content modules that help teachers better understand the science content they teach. This Science Object is the fourth of four Science Objects in the Rocks SciPack. It investigates how geologists have used rocks to help determine the approximate age of the Earth and provide a timeline of how the Earth’s surface and environments have changed over time. Scientists have tools to estimate the ages of rock and the overall time scale of the rock cycle. Some processes happen quickly and some happen slowly, but the oldest rocks indicate that the rock cycle has been recycling Earth’s material continuously for roughly 4 billion years. The same processes have been at work throughout Earth’s history, and therefore scientists can use the present to interpret the past. Observations of rock (textures, minerals, and fossils found within it) provides evidence of the environment and processes through which it formed, including the pressures, temperatures, and forces that created it.