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level: Level 3 - How the World Works

Questions and Answers List

level questions: Level 3 - How the World Works

QuestionAnswer
matterAny substance that has mass and takes up space by having volume.
solidA substance or object that is solid rather than liquid or fluid; particles are packed closely together and are not free to move about within the substance.
liquidA substance that is liquid rather than solid; particles move freely within the substance and it takes the shape of its container.
gasA state of matter that has no fixed shape and no fixed volume; particles move rapidly in all directions, frequently colliding with each other.
melting pointThe temperature at which a given solid will melt.
freezing pointThe temperature at which a liquid turns into a solid when cooled.
condensationWater which collects as droplets on a cold surface when humid air is in contact with it; the conversion of a vapour or gas to a liquid.
dissolve(of a solid) to become incorporated into a liquid so as to form a solution (e.g. salt dissolves in water).
chemical reactionA process that involves rearrangement of the molecular structure of a substance
solutionConsists of a solute and a solvent. The solute is the substance that is dissolved in the solvent (e.g. when combining salt and water: solute = salt and solvent = water).
filterA filter permits a fluid to pass through but retains the solid particles.
boiling pointThe temperature at which a liquid boils and turns to vapour.
soluble(of a substance) able to be dissolved, especially in water.
insoluble(of a substance) incapable of being dissolved.
reversibleA reversible change is a change that can be undone or reversed (e.g. melted ice can be re-frozen).
irreversibleA change is irreversible if it cannot be changed back again; a new material is formed (e.g. you can't un-bake a cake).
sieve (noun)An instrument with a meshed or perforated bottom, used for separating coarse from fine parts of loose matter, for straining liquids, etc.
temperatureA physical quantity that expresses hot and cold.
filtrationA process that separates solid matter and fluid from a mixture using a filter.
mixtureA material made up of two or more different substances which are physically combined (NOT a chemical change or totally new substance).
plasmaA state of matter that is similar to gas, but the atomic particles are charged rather than neutral.
sublimationThe transition of a substance directly from the solid to the gas state, without passing through the liquid state.
physical changeA change to the physical—as opposed to chemical—properties of a substance; they are usually reversible.
chemical changeChemical changes occur when a substance combines with another to form a new substance; usually irreversible.
vaporizationThe process in which a liquid boils and changes to a gas.
evaporationThe process in which a liquid changes to a gas, below boiling point.
viscosityA measure of a fluid's resistance to flow.
atomThe smallest particle of a chemical element that can exist.
particleA small portion of matter.
moleculeA particle made up of two or more atoms that are chemically bonded together.
massA measure of the amount of matter in an object.
densityA measurement that compares the amount of matter an object has to its volume.
volumeRefers to the amount of space an object takes up.
propertiesA characteristic or trait that you can use to describe matter by observation, measurement, or combination.
non-Newtonian fluidA fluid whose flow (viscosity) properties differ from those of Newtonian (regular) fluids.
phaseSynonymous with 'state', as in phases of matter and states of matter.
weightThe force acting on an object due to gravity.
variableAnything that can change or be changed; any factor that can be manipulated, controlled for, or measured in an experiment.
hypothesisA proposed explanation made on the basis of limited evidence as a starting point for further investigation.
testUnder controlled conditions, something that is made to demonstrate a known truth, or examine the validity of a hypothesis.
validityRefers to how well a scientific test or piece of research actually measures what it sets out to, or how well it reflects the reality it claims to represent.
rangeThe lowest to the highest value of your data is called its range.
reliableWhen a scientist repeats an experiment with a different group of people or a different batch of the same chemicals and gets very similar results then those results are said to be reliable.
tableAn arrangement of data in rows and columns
substanceA particular kind of matter that shares the same properties.
scientific methodA method of research in which a problem is identified, relevant data are gathered, a hypothesis is formulated from these data, and the hypothesis tested.
independent variableWhat the scientist changes or what changes on its own (e.g. age).
dependent variableWhat is being studied/measured (e.g. height at different ages).
control variableA person, group, event, etc., that is used as a constant and unchanging standard of comparison in scientific experimentation (e.g. if a temperature is unchanged during an experiment, it is controlled).
discrete dataDiscrete Data can only take certain values (e.g. the number of students in a class; we can't have half a student).
dataFacts and statistics collected together for reference or analysis.
correlationA measure of the extent to which two variables are related (e.g. the temperature outside and the number of people at the beach).
continuous dataContinuous Data can take any value--within a range (e.g. a person's height or weight could be any value).
averageA value that represents the sum of values divided by the number of values in the set.
scientific theoryAn explanation of something that can be repeatedly tested and verified in accordance with the scientific method.
trendTrends are general directions of data, such as an overall increase in global temperature.