Module5ALessoninaLab有两种变化:化学变化和物理变化,那么你知道化学变化和物理变化的区别吗
ChemicalChangeandPhysicalChangeTherearetwokindsofchange-chemicalchangeandphysicalchange
Inachemicalchange,thereisalwaysanewsubstanceformed
Breakingupwaterintohydrogenandoxygenisachemicalchange
Ineachofthechemicalchangeatleastonenewsubstanceisformed
Achangeisnotachemicalchangeifitdoesn'tformanewsubstance
Physicalchangesareverycommon,too
Therearemanyexamples
Youcanmakeaphysicalchangebytearingapieceofpaperintotwo,orbycuttingapieceofironwithalathe
Herethepaperisstillpaper,andtheironisstilliron
Anotherwayofmakingphysicalchangeisdissolvingsomethinginwater
Whenyoudissolvesaltinwater,thesaltdisappears
Youmaythinkthatanewsubstancehasbeenformed
Butinfactthereisnonewsubstance
Thesaltisstillsalt
Youcanstilltasteit
Sothedissolvingofanythingisa