1. Big Idea 9: Changes in Matter
Grade 5 Topic VI
Physical and Chemical Changes in Matter
Ms. Solernou

2. Words to know: Physical Changes, Chemical Changes Temperature
Phase changes
Melting, boiling, freezing
Evaporation, condensation
Reaction, combustion
evidence

3. All Matter has Properties, but Matter also undergoes Changes
Look at a cube of sugar. What are its physical properties?
It’s white. It’s shape is a cube. It smells sweet. It’s made of sugar crystals.
If you crush it, it will still be sugar. What was changed?
Only it’s shape. It is still made up of sweet, sugar crystals.
Engage and Explore:

4. Matter has physical properties that can be observed without changing the type of matter.
Matter can also change in ways that do not affect the type of matter.
These changes are called physical changes.

5. Take a piece of paper and change it in some way
How did you change it?
Folding Bending
Tearing Cutting
Crumpling
Why are the changes that you all made to the paper just physical changes?
The paper is still paper. You can unfold it.
Explore:

6. More on Physical Changes
What is happening to the ice cubes?
They’re melting.
If you add enough heat energy to ice, it turns into liquid water, then it turns into a gas called water vapor.
If you cool the substance, by taking away heat energy, you can reverse these changes.
You can change a gas into a liquid and
a liquid into a solid.
What type of change is this?
Changing from one state to another state is an example of a physical change.
Explore and Explain:

7. *Water boils at 100 ̊ Celsius or 212 ̊ Fahrenheit
States of Water
Water changes to steam( gas), when it is heated to its boiling point*, As water vapor cools it condenses back to form a liquid
*Water boils at 100 ̊ Celsius or 212 ̊ Fahrenheit
Explain:

8. Solid, Liquid and Gas
If you add enough heat energy to liquid water, it turns to gas (water vapor).
If you cool the substance by subtracting heat energy, you can reverse these changes.
You can turn a gas into a liquid and a liquid to a gas

9. Gold…
Any element can become a gas; you just need to heat it past its boiling point.
For gold, that’s 2,856 degrees Celsius (5,173 degrees Fahrenheit), which is hotter than the temperature in an arc furnace so it’s difficult to just boil a bar of gold.
But you can create small amounts of gold gas by bombarding it with a high-energy beam of electrons in a vacuum. Not an easy task to do, but has been done!

10. Almost all substances, can exist in all three States of Matter
(solid, liquid, and gas state)
They just have different freezing and boiling points.
All you have to do is add or subtract enough heat energy!

11. REMEMBER…
A CHANGE IN STATE ALWAYS HAPPENS AT THE SAME TEMPERATURE FOR A PURE SUBSTANCE…
GOLD WILL ALWAYS MELT AT THE SPECIFIC MELTING POINT.

12. Did you know?
Water is the only common substance on Earth that exists in all three states at ordinary temperatures

13. Freezing Point
The freezing point of a substance is the temperature at which it changes from a liquid to a solid.
A substances freezing point is the same as its melting point.
Ice melts at 0 º C
Water freezes at 0 º C

14. Melting Point
The melting point of a substance is the temperature at which it changes from a solid to a liquid.
The melting point of water is 0 º C.
When ice is heated to 0 º C, it begins to melt.

15. Boiling Point
The boiling point of a substance is the temperature at which it changes rapidly from a liquid to a gas.
The boiling point of water is 100 º C.
When water is heated to a temperature of 100 º C, it begins to boil.
The water molecules escape from the liquid and enter the air as a gas.

16. Condensation
When molecules of water vapor are cooled, they condense and form liquid water.
The condensation point of a substance is the temperature at which it changes from a gas to a liquid.
Water boils at 100 º C,
Water vapor condenses at º C

22. Physical change is often due to a change in temperature
How does heat affect physical changes?
Some types of matter change state when enough heat is added to it (melting) or taken away from it (freezing*).
ICE MELTS AT 0 ˚ C
WATER FREEZES AT 0 ˚ C
Explore: Click on the hyperlink: Physical change is often due to a change in temperature and explore a FOSS site showing the effects of objects placed in the freezer. Review with students the temperature of the freezer - 0 ̊ Celsius or 32 ̊ Fahrenheit
Explain and evaluate: Answer How does heat affect physical changes? Have students give examples. *

23. DID YOU KNOW?
THE VOLUME OF MANY SUBSTANCES, INCLUDING MOST METALS, INCREASE AS TEMPERATURES INCREASE.

24. On a hot summer day, telephone wires sag between the poles that hold them up. Yet, on a cold day, the wires are tightly stretched. The reason is that most substances expand as they get hotter, and contract, or shrink, as they cool down.
Metals, when heated, expand more than other kinds of solids do. Because of this, engineers have to be especially careful when designing and building large metal structures. For example, narrow gaps must be left between railroad tracks at regular intervals. This prevents the tracks from buckling during hot weather.

25. CAN YOU THINK OF A WAY TO OPEN A VERY TIGHT BOTTLE?

26. REMEMBER THAT METAL EXPANDS AND MOVES AWAY FROM GLASS.
THEREFORE, WHEN YOU PLACE A BOTTLE OF NAIL POLISH IN HOT WATER, WITHIN A FEW MINUTES YOU CAN OPEN IT EASIER…

27. What are some Different Ways that Matter Changes Physically?
Crushing
Folding
Bending
Tearing
Cutting
Crumbling
Sanding
Smashing
Peeling
Melting *
Freezing *
*A process in which a type of matter changes state when enough heat is added to it (melting) or taken away from it (freezing).
Explain and evaluate:

28. A CHANGE IN STATE THAT DOES NOT CHANGE THE COMPOSITION OF A SUBSTANCE IS A __________________ CHANGE.
WHICH CONDITION HAS THE GREATEST EFFECT ON HOW QUICKLY A SUBSTANCE CHANGES FROM ONE STATE TO ANOTHER?
YOU ARE RIGHT: TEMPERATURE

29. CHEMICAL CHANGES

30. Making Cookies
Imagine that you and your mom are making cookies. You mix all the ingredients together in a bowl. Next you spoon out cookie dough onto a baking sheet. Then you place the sheet in a hot oven to bake. The change that turns the dough into a cookie is called a _____________. Yes, a chemical change Chemical changes are also called reactions. Why?
Engage and explain:

31. Chemical Changes What are some examples of chemical changes?
Chemical changes produce new substances that have different properties than the original substances.
What are some examples of chemical changes?
Burning
Rusting
Cooking and baking
Explain

32. What are some signs of a chemical change that can be seen?
Signs or clues can include:
Change in odor
Change in color
Change in taste
Change in mass
Forming bubbles (giving off a gas)
Giving off smoke
Giving off light
Explain

33. Chemical changes change the chemical nature and properties of substances to form new substances
What are some examples of chemical properties?
Corrosion of metal—when iron combines with oxygen in the air, rust forms
Gas bubbles— Baking soda combines with vinegar, carbon dioxide forms
A change in color (browning of fruit - decay) – an apple is peeled and there is a quick reaction with oxygen in the air
Explain and evaluate:

34. More on Chemical Changes
Chemical changes can happen quickly or slowly.
Chemical changes to matter can be produced by heating.
Light energy can produce a chemical change in some materials.
Sometimes when two substances combine, energy is released.
Chemical changes are often difficult to reverse.
Explain and evaluate:

35. Compare and Contrast Property Changes
Physical Change
Chemical Changes
A physical change is a change in the physical properties of matter. The matter changed in how it looks, but what it is made out of does not change.
A change that takes place when a substance changes in size, shape or form. The particles of matter do not change.
A chemical change is a change in the chemical properties of matter. A chemical change occurs when two or more kinds of matter combine to form a new substance with different properties.
A change that takes place when a substance is completely altered. The particles of matter do change.
Explain and Evaluate:

36. WHY SHOULD WE KEEP MILK IN THE REFRIGERATOR?
IN MILK, CHEMICAL REACTIONS CAUSE FORMATION OF NEW SUBSTANCES AS MILK SPOILS.
THIS HAPPENS MORE SLOWLY AT LOW TEMEPRATURES.
IN OTHER WORDS, MILK WILL EVENTUALLY GO BAD, IF YOU DON’T DRINK IT, BUT MAINTAINING IT IN COOL TEMPERATURE ALLOWS THE MILK TO STAY FRESH LONGER.

37. Review 1. What is a chemical change?
Answer: A chemical change produces substances that have new properties.
2. How is a chemical change different than a physical change?
Answer: A physical change does not produce new substances like a chemical change does. It only changes physical properties.
3. How is heat involved in chemical changes?
Answer: Sometimes heating can cause chemical changes. Sometimes chemical changes give off heat.
4. How is heat involved in physical changes?
Answer: Sometimes adding heat to matter can change its state -when enough heat is added to it can cause melting or if heat is taken away it can cause freezing of the matter.
Explain and evaluate:

38. WHAT ARE THE CHEMICAL CHANGES?
WOOD BURNING?
SMOKE FORMING?
MARSHMALLOWS TURNING GOOEY AND BLACK?
AIR EXPANDING AND MOVING AWAY FROM THE FIRE?
HINT: AIR DOES NOT BECOME A DIFFERENT SUBSTANCE AS IT HEATS AND EXPANDS…