By Colin Ng(6) of 1O2

1. Change in state of matter By Colin Ng(6) of 1O2

2. These are the changes of states • Freezing

3. Evaporation I know I know !!It happens only on the surface of water as molecules liked to move from areas of higher pressure to lower pressure. The molecules are basically sucked into the surrounding area to even out the pressure. • The process which a liquid’s (example a puddle of water) molecules becomes a gas • happens when atoms or molecules escape from the liquid and turn into a vapor • Can happen when liquids are cold or when they are warm Do you know why evaporation only happens only on the surface of water?

4. Experiment you can do Things you will need: ~a large measuring jug ~ salt, a stick of chalk ~two bowls (both the same size) ~ a tape measure ~a plastic ruler

5. Experiment you can do • Step 1 :Find two spots - a sunny area and a shady area of concrete • Step 2 :Dissolve some salt in a large measuring jug of water • Step 3 :Pour an equal amount of water onto the concrete forming two big puddles one in the sun and the other in the shade. Trace a line around the outside of each puddle • Step 4 :Dissolve some more salt in some water and pour an equal amount of this into each bowl. Then place a bowl of salted water next to each puddle

6. Experiment you can do • Step 5 :Measure across both the puddles with the tape measure and then measure the depth of the water in both the bowls with the plastic ruler and record the four measurements • Step 6 :Return to the area every hour and keep measuring the puddles. You can keep drawing new lines around the puddles as they get smaller. Also check the jars each day to see what happens to the water and salt.

7. Melting Heat is taken in in the process of melting… • is a process that results in the change of a substance from a solid to a liquid • The energy of a substance is increased, typically by the application of heat or pressure, resulting in a rise of its temperature to the melting point, at which the rigid ordering of molecular entities in the solid breaks down to a less-ordered state and the solid liquefies

8. Experiment you can do Things you will need: ~Ice pieces ~Evaporation dish

9. Experiment you can do Experiment Leave ice pieces on a evaporation dish. Observe it every one hour and record it. What will you observe?

10. Condensation • is the formation of liquid drops from water vapor • usually occurs when a parcel of rising air expands and cools • occurs during the formation of dew • keeps the Earth's climate cooler that it would otherwise be if there were no water Now I know what is condensation!!

11. Experiment you can do Things you will need ~yourself • In cold weather Breathe out outdoor. What do you observe?

12. Experiment you can do • Things you will need • ~ a glass of icy cold water • ~ evaporating dish • ~a fridge • In hot weather Pour out a glass of icy cold water from the fridge on a evaporating dish during a hot days. What do you observe?

13. Sublimation • is the term for when matter undergoes a phase transition directly from a solid to gaseous form, or vapor, without passing through the more common liquid phase between the two • Heat energy is absorbed when solid changes into a gas • Heat is given out when a gas change into a solid

14. Experiment you can do Things you will need ~a spoon ~dry ice ~Bunsen burner

15. Experiment you can do Experiment First, To begin, warm a spoon by holding it above a flame for a few minutes. Next, place the spoon firmly against the chunk of dry ice. What will you observe?

16. Deposition • Is a process in which gas transforms into solid (also known as desublimation) • Is the reverse of deposition is sublimation • One example of deposition is the process by which, in sub-freezing air, water vapor changes directly to ice without first becoming a liquid • This is how snow forms in clouds, as well as frost and hoar frost on the ground Another example of physical deposition is the artificial process of physical vapor deposition, used to deposit thin films of various materials onto various surfaces!

17. Freezing Did you know that the temperature of a liquid stays constant in the process of freezing… • Is the process in which a liquid turns into a solid when cold enough • Happens at 0°C  for pure water • Heat is given out in the process • is a common method of food preservation which slows both food decay and the growth of micro-organisms Of course, I knew about it the moment I was born!! Also, I knew that when a liquid freezes, its particles slow down to take up fixed and orderly position in the solid.

18. Experiment you can do • Things you will need: • ~Water • ~Freezer • ~Cooking Oil • ~Clear Plastic Container (like a glass or cup)

19. Experiment you can do • Steps: •  Pour some water into the clear plastic container • Add some cooking oil •  Leave this for a few minutes •  Put the container into the freezer for a few hours •  Remove from freezer. The oil is now underneath the water

20. Videos about the changes of state • http://www.youtube.com/watch?v=y9Nou6g-zwQ&feature=related( evaporation) • http://www.youtube.com/watch?v=qbQjukRmLSg(melting) • http://www.youtube.com/watch?v=HF_hLpH2yaQ&feature=related(freezing) • http://www.youtube.com/watch?v=dABCmlq2MNY&feature=related(condensation) • http://www.youtube.com/watch?v=0_LWBgeQrvk&feature=related(sublimation)

21. Questions Note: please answer the question on a piece of writing paper. I will mark it! The one who got the most correct will get a prize. • What are the 6 changes in state? • What is the change of state for Deposition, Sublimation, Melting, Freezing, Evaporation and Condensation? ( Example: Melting-from solid to liquid) • Why evaporation only happens at the surface?

22. Questions Note: please answer the question on a piece of writing paper. I will mark it! The one who got the most correct will get a prize. • 4) What is one example of Deposition? • 5) Heat is taken in or given out for sublimation? • 6) What are the brief description of each change?(Example: Evaporation is the process which a liquid’s (example a puddle of water) molecules becomes a gas)

23. Biblography • The Encyclopedia of World • http://www.wardthomas.com/surveyform/images/Kitchen/elec_fridge_.jpg • http://www.chem4kids.com/ • http://www.meltingpot.com/locations.aspx • http://www.weatherquestions.com/What_is_condensation.htm • http://www.ace.mmu.ac.uk/eae/weather/older/condensation.html

24. Thank you!! Any question?