Fire Science Flashcards
To memorise formulas
Velocity of Water
d²
Discharge of Water
20
Jet Reaction
10
Capacity of a Hoseline
10,000
Discharge through nozzle
3
Loss of Pressure due to friction
d⁵
Water Power
60
Efficiency of Pump
WP
—- x 100
BP
Quantity of Water
V x A
Define Liquids of Different Density
Whether a liquid will rest on top of another for example petrol on water, thus determining which firefighting extinguishing media to use
Define gases of different density
Whether gas will rise or fall in air. This could lead you to where a leak of a substance is collecting
What is density ?
Density of a material in defined as the mass of one cubic metre of material. To calculate density is D = mass/volume
If the mass is kg and the volume is cubic metres density is kg/cm3
If mass is grams and the volumes is cm, density is g/cm3
If the figure is lower than 1 it floats, if it’s higher that 1 it sinks
What is relative density
Also known as specific gravity (gravity)
The ratio of the mass of any volume of it to the mass of an equal amount of water.
Relative Density =. Mass of any volume of the substance
Mass of an equal volume of water
No units involved.
What is vapour density?
The measure of density of a vapour or a gas in relation to equal amounts of hydrogen. Air is also sometimes used as a measure as you will be able to see whether it rises or falls in normal conditions.
What is matter
It exists in 3 states. Solid Liquid and Gas
What are atoms?
Atoms are tiny particles that are too small to see. Everything is made of atoms, there different types of atoms, these are called elements, the elements all have different symbols.
What are molecules?
Molecules are atoms chemically bound together.
Discuss elements.
Elements contain only 1 sort of atom either alone or grouped into molecules containing 1 type of atom.
What are Compounds?
Compounds are formed from only 1 type of molecule which contains more than 1 kind of atom
What is a mixture
Mixtures contain more than 1 kind of molecule.
Describe an Atom
Atoms have a central core or nucleus which contains smaller particles called protons and neutrons. Protons have a positive charge. The nucleus is surrounded by a system of electrons which each carry a negative electrical charge. Atoms contain as many electrons as protons. This means they are neutral.
Greek for indivisible, until about 70years ago, Greeks believed that atoms could not be split. We now know that atoms of one element can be ‘split’ or combined with other particles to make new atoms of other elements.
What is energy
Energy is expended in doing work and may be in one of a number of different forms heat, light and electrical energy, potential and kinetic
What is potential energy
Possessed by a body due to its position
What is kinetic energy
Possessed by a moving body
What is an element
An element is a substance which contains atoms which are all of the same type: they all have the same number of protons.
As there are can be anything up to just over 92 protons in an atom, there are just 92 stable elements. Atoms of different elements can combine to form molecules.
Discus compounds
Some molecules consists of two or more atoms of the same kind: for example, an oxygen molecule consists of two oxygen atoms (O2). Other molecules consist of two or more atoms of different kinds: carbon dioxide consists of two atoms of oxygen and one of carbon (CO2), water consists of two hydrogen atoms and one oxygen (H2O). Carbon dioxide and water are chemical compounds and they can, by chemical means, be split into their component elements.
What is temperature ?
Temperature is a measure of how hot something is and is related to how fast the constituent molecules are moving.
