2.4.2 Relativity, space, time and gravity

Throughout the development of mechanics and electromagnetism the role of space and time had been clear and simple. Space and time were simply the arena within which the drama of physics was played out. Speaking metaphorically, the principal ‘actors’ were matter and ether/fields; space and time provided the setting but didn't get involved in the action. All that changed with the advent of the theory of relativity.

The theory was developed in two parts. The first part is called the sp
Author(s): The Open University

2.3 The irreversible Universe

From the time of Newton until the end of the nineteenth century the development of physics consisted essentially of the refinement and extension of the mechanical view of the Universe. There were many stages in this process but one of the most interesting came towards its end with the re
Author(s): The Open University

7.6 Synaptogenesis

The formation of synaptic connections is an essential property of nervous system development. Synapses are formed between neurons and also with targets that are not part of the nervous system, e.g. muscle. Axon terminals, under the direction of a variety of extracellular cues, grow towards particular targets. Once they arrive at the target, they stop growing and the growth cone changes to form a synapse. As with axon growth, the formation of the synapse is dependent on an interaction between
Author(s): The Open University

2.3.2 Salinity, desiccation and biotic interactions on seashores

Tidal movements ensure that sea-shore habitats are, if not covered by seawater for part of each day, at least subject to spray-borne salt and wind. So, even well above the level of high tides, sea-shore organisms need to be more tolerant of salt than most terrestrial organisms. However, salinity (the concentration of salts dissolved in water) is not the only factor affecting sea-shore species. Seaweeds and shelled animals like limpets and barnacles are adapted to living in a highly saline mar
Author(s): The Open University

2.1 Introduction

Ecology is usually defined as the study of organisms in their environments. In its broadest sense this definition includes the way we, the human species (Homo sapiens), interact with and use the environment. However, in the sense in which most ecologists work, ecological studies are limited to studies
Author(s): The Open University

AP Chemistry: Bonding MC Question Practice