A region of space-time where gravity prevents anything, including light, from escaping

Water from toilets, kitchen sink, or other dirty sources, which could be contaminated with microorganisms or harmful bacteria.

To determine or check the accuracy of an instrument used for quantitative measurements, or to make corrections in or to adjust an aspect of a system

A unit of energy (heat)

The cycle by which carbon is exchanged between the Biosphere, geosphere, hydrosphere and atmosphere of the Earth.
Major activities include photosynthesis, respiration and decay between atmospheric and terrestrial systems.

The greenhouse gas whose concentration is being most affected directly by human activities. The major source of emissions is fossil fuel combustion.

A measure of the effect that human activities have on the climate in terms of the total amount of Greenhouse gases produced

A tax on energy sources which emit Carbon dioxide into the atmosphere. It is an example of a pollution tax.

The weak acid formed when COâ‚‚ dissolves in water.

A theoretical formulation of the most efficient thermodynamic cycle capable of converting thermal energy into work, and work into thermal energy. A defining characteristic of the Carnot Cycle is that it does not consider a change in entropy, and thus cannot exist in real practice

Categoric variables have values that are labels. Eg names of insects or types of material.

A positively charged ion that migrates to the cathode in an electrical cell.

A change in one variable that results from or is caused by a change in another variable

The smallest structural and functional unit of an organism, typically microscopic and consisting of cytoplasm and a nucleus enclosed in a membrane

The acceleration of an object moving in a circle at a constant speed. Centripetal acceleration always acts towards the centre of the circle

When fission neutrons cause further fission, so more fission neutrons are released. This goes on to produce further fission.

Consortium of Local Education Authorities for the Provision of Science Services

http://science.cleapss.org.uk

Climate change refers to the variation in the Earth's global climate or in regional climates over time. It describes changes in the atmosphere over time scales ranging from decades to millions of years. These changes may come from processes within the Earth, or be caused by human activities

A confounding variable is one that may, in addition to the variable independent variable, affect the outcome of the investigation. Confounding variables must be kept constant or the investigation will not be a fair test. Confounding variables are sometimes referred to as control variables.

In a closed system, the momentum before a collision/event is equal to the total momentum after the collision/event.

A force that acts at the point of contact between two objects

Continuous variables can have values (called a quantity) that can be given a magnitude either by counting (as in the case of the number of cars) or by measurement (eg electrical current, speed etc).

A control experiment is one that is set up to eliminate certain possibilities. In a well designed investigation, the independent variable is changed and all confounding variables are kept constant. The possibilityexists, however, that something else other than the independent variable might have produced the results that were obtained. A control experiment is one that is designed to eliminate this possibility

A control group is one that is treated in exactly the same way as the experimental group except for the factor that is being investigated. This allows scientists to make a comparison. It ensures that the data that are collected are valid because any differences between the results for the experimental group and those for the control group will be due to a single independent variable.

A control variable is one which may, in addition to the independent variable, affect the outcome of the investigation and therefore has to be kept constant or at least monitored.

A lens that makes light rays near and parallel to the principal axis converge to a point, known as the principal focus

A correlation shows that there is a relationship between two variables, however, it might not be a causal one

Crotalus atrox, the western diamondback rattlesnake, is a venomous rattlesnake species found in the United States and Mexico. It is likely responsible for the majority of snakebite fatalities in northern Mexico and the second-greatest number in the U.S., after C. adamanteus.