Standard+5d

(Q. 34, 35, 36, 37, 38, 39) The following things are examples of phase changes: 1) Sold melting to liquid and liquid freezing to solid (occur at the melting point/freezing point: which is specific and unique for each substance) 2) Liquid to gas (boiling point) or liquid to gas (evaporation), and gas to liquid (occurs at boiling point/condensation point) These changes are reversible: you can always re-freeze it, re-melt it, etc. They are called physical changes. Also, dissolving something is a physical change because it can be reversed by evaporating the liquid. Another example is a mixture of iron filings and sand: they can be separated by using a magnet! Chemical changes mean that the atoms have permanently been changed into new molecules. This happens a lot in cooking, for example. ACTIVITY: 1) Write a summary for the information above, in your journal. 2) Physical v. Chemical changes: http://www.teacherbridge.org/public/bhs/teachers/Dana/chemphys.html 3) TAKE QUIZ HERE: https://www.quizlab.com/secured/authenticate_limited.cfm Click on "single class login", and input classword (tewinkle(#ofclass): ex. if you are in period 2, your classword is tewinkle2, Your password is first letter of name and as much of last name as fits (ex: htangen).
 * //Students know//** **//physical processes include freezing and boiling, in which a material changes form with no chemical reaction.//**