Pre-class Activity 9/11

Chemistry is the study of matter and the changes that it undergoes.

What is matter? Be prepared to give two examples of matter that can be found in the classroom

Chemistry and Matter

Chemistry is the study of matter and the changes that it undergoes.

Anything that has mass and takes up space

A measurement that reflects the amount of matter

Questions

What in the universe isn’t matter?Energy

Why aren’t the terms mass and weight interchangeable?

Weight is not only a measure of the amount of matter, but also a measure of the effect that gravity has on matter

Scientific Method – A Systematic Approach

OBSERVATION HYPOTHESIS EXPERIMENT THEORY

Draw conclusions and revise hypothesis

Theories are supported by many

experiments

SCIENTIFICLAW

Theory vs. Law

Arise following

many, many experiments

Provides an explanation of what occurs in nature

Merely states what occurs in nature

Observations

Hot 300o

Qualitative vs. Quantitative

Temperature

Height

Mass

Length

Pre-class Activity 9/8 A scientist owns fish that are very sensitive to

changes in temperature. One morning, after a huge storm, he came into the lab only to find that all the fish in his tank were dead. He suspected that there might have been a power outage due to the storm, in which the power to the heater may have been interrupted. To test this, he measured the temperature of the tank, only to find that it is normal.

Identify the observation, hypothesis and experiment in the paragraph above. Does the result of the experiment support the hypothesis?

Homework: Read The Milk Lab, continue with HW assignments 1,2,3. Homework Assessment #1 – Wednesday 9/10

Mrs. Pav’s Milk Lab Write-Up

Pupose: To determine if the type of milk affects the migration time of food coloring in the milk experiment

Hypothesis: If whole milk is substituted for skim milk in the milk experiment, the food coloring will migrate slower.

Materials: In addition to materials listed for the milk lab, whole milk was added

Procedure: Refer to written procedure for the milk lab. The migration time of food coloring was measured by using a stop watch to record the time that it took for the food coloring to migrate to the edge of the petri dish.

Results: The time for the control (skim milk) was 4.8 seconds. The time for the experimental group (whole milk) was 3.2 seconds.

Conclusions: The hypothesis was confirmed by the data because the migration time of food coloring increased for whole milk as compared to skim milk

ExperimentsA set of controlled observations that test a hypothesis.

Key Terms

Variable: A quantity or condition that can have more than one value

Independent Variable: A variable that is changed by the investigator in an experiment

Dependent Variable: A variable the changes in response to the independent variable

Control: A standard for comparison

Experimental Design Example

The Effect of Temperature on the Respiration Rate of Fish

Temp (oC)

Res

pira

tion

Rat

e

What is the dependent variable?

What is the independent variable?

What would be an appropriate control?

What is the relationship between respiration rate and Temperature?

Theory vs. Scientific Law

Theories are explanations that are supported by many experiments

Scientific Law describes a relationship in nature that is supported by many experiments

Pure vs. Applied Research

Gaining knowledge for the sake of knowledge

Vs.

Gaining knowledge to solve a specific problem

TOP 3 CHOICES FOR LAB PARTNERS

COOPERATIVE CONSCIENCIOUS RELIABLE

SOMEONE TO WORK WELL WITH

CONSCIENCIOUS RELIABLE A SUCKER

SOMEONE TO DO ALL THE WORK

DEVIANT MISCHIEVIOUS STAYING AFTER SCHOOL TO

WASH GLASSWARE

SOMEONE TO GOOF OFF WITH

CREDITS

DIRECTION AND PHOTOGRAPHY……………MRS. PAV

SCIENTIST, SLACKER AND

MISCHIEF MONKEY #1………………………….GARCIA PAV

SCIENTIST, SUCKER AND

MISCHIEF MONKEY #2…………………………OLIVIA PAV