Examples of reversible change

Middle ChildhoodREVERSIBLE AND IRREVERSIBLE CHANGESGlossaryChanging statefrom solidto liquidto gasand back again isa reversible change.PHYSICAL CHANGEAny reactionsuch as burning that causes new substancesto be formed is called a CHEMICAL CHANGEthe changes are irreversible.Fuel +Oxygen+FlameAsh +Smoke +Heatheating –the process of increasing the temperatureash–a new substance formed when materials burnirreversible change –a change that cannot easily be reversed e.g. burningburning–a chemical change that is irreversible. Burning involves fuel, oxygen and a flame –heat, smoke and ash are produced when things burnphysical changes-are reversible changes –no new substances are produced following the changechange of state–the process of change from one stateof matter to another –this is a reversible changeWhen chocolate is meltedit can solidifyagain. The change is reversible.Cooking eggs by frying, boiling, scrambling, poaching etc. is always an irreversible change.precipitate–the name of a solid produced in some chemical reactionschemical changes–are irreversible changes -new chemicals are produced following the changereaction–To react -verbdissolving –the process of a substancebecoming part of a liquid –this is a reversible changerenewable energy–a source of energy that does not involve the burning of fossil fuels e.g. wind powereffervesce–to fizz –giving off a gas e.g. soluble antacid tablets –this is an irreversible changeDissolving sugar in water is a reversiblechange. When the water is evaporatedit leaves the sugar behind. When oil, vinegar and egg yolks are mixed the resulting precipitateis mayonnaise. This change is irreversible.Coal, gas and oilare all fossil fuels. They are also examples of non-renewableenergy sources. reversible change–a change that can be easily reversed e.g. freezing water to make icefossil fuel–fuel that comes from the remains of dead animals and plants e.g. coal, oil, gassubstance–a materialhazard –a danger tohealth and / or lifeThis wind turbineis part of a wind farmhelping to generate electricity from renewable sources. Here are some hazardsymbols –do you know what they mean?Heatingis the process of increasing the temperature. Coolingisthe opposite process where temperature is decreased.We use a thermometerto measure temperature.When vitamin tablets effervesce(fizz) a gas is produced. This is an irreversiblechange.