Acceleration is the rate of change of velocity with respect to time. It is a vector quantity, meaning it has both magnitude and direction. When an object accelerates, it changes its velocity either by speeding up, slowing down, or changing direction.
History and Nature of Science: A student should understand the history and nature of science. A student who meets the content standard should:
Develop an understanding that historical perspectives of scientific explanations demonstrate that scientific knowledge changes over time, building on prior knowledge.
Develop an understanding that scientific knowledge is ongoing and subject to change as new evidence becomes available through experimental and/or observational confirmation(s).