Section 200.22 Program standards for behavioral interventions. Behavioral interventions for students with disabilities shall be provided in accordance with this section and those other applicable provisions of this Part and/or Part 201 that are not inconsistent with this section. (a) Assessment of student behaviors.
The age of Earth was calculated to be about 24-40 million years based on the laws of thermodynamics. Unknown at the time was that the Earth has an internal heat source (radioactive decay) In 1899, John Joly (Irish) calculated the rate of delivery of salt to the ocean.
So to determine the age of sedimentary rock layers, researchers first have to find neighboring layers of Earth that include igneous rock, such as volcanic ash. These layers are like bookends -- they give a beginning and an end to the period of time when the sedimentary rock formed. By using radiometric dating to determine the age of igneous brackets, researchers can accurately determine the age of the sedimentary layers between them. Using the basic ideas of bracketing and radiometric dating, researchers have determined the age of rock layers all over the world. This information has also helped determine the age of the Earth itself. While the oldest known rocks on Earth are about 3.5 billion years old, researchers have found zircon crystals that are 4.3 billion years old [source: USGS]. Based on the analysis of these samples, scientists estimate that the Earth itself is about 4.5 billion years old.