p. 178 q2: why does water change from a solid to liquid when it is heated? (wrt particle theory) ...

p. 178

Q2: Why does water change from a solid to liquid when it is heated? (WRT particle theory)

Q3: 3 examples of a pure substances. Q4: 3 examples of a mixture Q5: describe mechanical mixture Q6: describe a solution.

p. 178

Q8: MM or S? Pane of clear glass Chocolate chip ice cream Clear apple juice A pizza Garbage in a garbage can

Q9: what kind of alloy makes an effective solder material? (Sn and Pb)

Q10: Lead is not used in solder anymore, why?

Making Observations and Inferences

Observations

Observations: Using our senses to gather information about the world around us.

There are two types of observations.

Qualitative

Qualitative observation: (quality) Usually made with our senses. Color, shape, feel, taste, sound.

Examples:

Olivia is wearing a blue sweater.

The lab tabletop is smooth.

The dog’s fur is shiny.

Quantitative

Quantitative observation: (quantity) How many. Will always have a number. Based on exact measurement.

Examples:

The room is 8 meters across.

Sarah is 141 cm tall.

Sam weighs 450 Newtons.

Inferences

Inference: A logical interpretation of an event that is based on observations and prior knowledge.

Making InferencesYou are at the counter in the office to get a bus pass signed. You see a student leave the principal’s office crying and upset. We could make an inference as to

why the student is upset. Could be in trouble

Student not feeling well Student has poor grades

Observation vs. Inferences

Observation – Based on the five senses: Sight, Smell, Touch, Taste, Hearing

Inference – Based on prior knowledge or opinion In laboratory exercises, record observations NOT

inferences Inferences may be used when writing the conclusion

in your lab report.

Observation vs. Inferences

Does the square have curved sides?

Where are those dots coming from?!

Can you pick the tallest soldier?

These circles are not moving!

Are these dots moving?

Take a good look at the following picture

Questions:

Q1: Are there cars parked on the sides of the road? Q2: What color is the pickup truck driving in the road? Q3: Are there any minivans around?Q4: What does the blue sign say?Q5: What’s the speed limit?Q6: Are there any pedestrians on the road?

Questions:

Q1: Are there cars parked on the sides of the road? YESQ2: What color is the pickup truck driving in the road? BLUEQ3: Are there any minivans around? YESQ4: What does the blue sign say? Yard SaleQ5: What’s the speed limit? 35 mph Q6: Are there any pedestrians on the road? No

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Variables Independent variable: The variable being tested Dependent variable: The variable that changes (what

happens during the experiment) Control variable: A ‘normal’ variable. Used for comparison.

Hypothesis: An educated guess If INDEPENDENT VARIABLE, then DEPENDENT VARIABLE

The Problem/Purpose

Mrs. Soloman (the Principal) believes that a special juice from GNC health foods will increase the productivity of teachers at John Fraser SS. She creates two groups of 50 teachers each. One group

will drink the 'special juice' and the other will drink water with blue food colouring. The task she

asks them to complete is stapling sets of paper together. After one hour Mrs. Soloman counts how many sets of papers were stapled by each group.

Identifying Important Information

Mrs. Soloman (the Principal) believes that a special juice from GNC health foods will increase the productivity of teachers at John Fraser SS. She creates two groups of 50 teachers each. One group will drink the 'special juice' and the other will drink water with blue food colouring. The task she asks them to complete is stapling sets of paper

together. After one hour Mrs. Soloman counts how many sets of papers were stapled by each group.

Control variable: Group that drinks waterIndependent variable: Special juiceDependent variable: Productivity of teachers

What would be an appropriate hypothesis for this experiment?

The Problem/Purpose

Mr. Chawla notices that his shower is covered in green slime. Miss. Adams

suggests that Mr. C use coconut oil to get rid of the slime. Mr. C decides to use the coconut oil on half the shower and plain water on the other. After three days of

'treatment' there is no improvement with respect to the slime.

Identify the control variable; independent variable and dependent variable

What should Mr. C's conclusion be?

The Problem/Purpose

Mr. Miller wants to test whether a new hair growth treatment works. He decides to use Hair for the Head (hair growth cream) on half of his

head and leaves the other side bare.

Identify the control variable; independent variable and dependent variable

What would be an appropriate hypothesis for this problem?

REMEMBER THE RULE FOR WRITING HYPOTHESIS!

If independent variable, then dependent variable

Observations and Inferences

Examples1. The concert was loud2. There are 35 students in the class3. When a student gets sent to the office it means they are in trouble4. Yao Ming is 7 feet 6 inches tall5. The chemical smelled like sulfur6. First period on day 1 is 115 minutes7. Students at Stephen Lewis are smart8. The water is cold9. Tall people are good at sports10. A large coffee from Tim Horton's costs $1.52

Chemical Versus Physical Properties

Chemical Properties A characteristic of a

substance that is determined when the composition of the substance is changed and one or more new substances are produced.

Examples: combustibility, reactivity

Physical Properties A characteristic of a

substance that can be determined without changing the composition of that substance.

Examples: Lustre (shininess/dullness), optical clarity (transparent, translucent, opaque), brittleness (breakability), viscosity (resistance to flow)

Chemical Versus Physical Changes

Chemical Changes Bubbles form (gas

production)*** A new colour appears

Heat or light is given off A precipitate forms *** The change is difficult to

reverse

Physical Changes A change that affects the

size, shape or colour of a substance but does not affect its composition

Activities

Stations 1-5 Identify the particular chemical/physical property

of the substance at each station.

Write one sentence explaining your answer

Stations 6-10 Follow the procedures at

each station. Identify the reaction as

physical or chemical Write one sentence explaining you answer

P. 182 Q: 2, 4, 5P. 186 Q: 2 - 7