Investigation and Experimentation

Investigation and ExperimentationThe Scientific Method,

Lab Equipment, Measuring, and

Lab Safety

Standards• 1. Scientific progress is made by asking meaningful questions and conducting careful

investigations. As a basis for understanding this concept and addressing the content of the other four strands, students should develop their own questions and perform investigations. Students will:

• a. Select and use appropriate tools and technology (such as computer-linked probes, spreadsheets, and graphing calculators) to perform tests, collect data, analyze relationships, and display data.

• b. Identify and communicate sources of unavoidable experimental error.

• c. Identify possible reasons for inconsistent results, such as sources of error or uncontrolled conditions.

• d. Formulate explanations by using logic and evidence.

• e. Solve scientific problems by using quadratic equations and simple trigonometric, exponential, and logarithmic functions.

• f. Distinguish between hypothesis and theory as scientific terms.

• g. Recognize the usefulness and limitations of models and theories as scientific representations of reality.

Standards Cont.• h. Read and interpret topographic and geologic maps.

• i. Analyze the locations, sequences, or time intervals that are characteristic of natural phenomena (e.g., relative ages of rocks, locations of planets over time, and succession of species in an ecosystem).

• j. Recognize the issues of statistical variability and the need for controlled tests.

• k. Recognize the cumulative nature of scientific evidence.

• l. Analyze situations and solve problems that require combining and applying concepts from more than one area of science.

• m. Investigate a science-based societal issue by researching the literature, analyzing data, and communicating the findings. Examples of issues include irradiation of food, cloning of animals by somatic cell nuclear transfer, choice of energy sources, and land and water use decisions in California.

• n. Know that when an observation does not agree with an accepted scientific theory, the observation is sometimes mistaken or fraudulent (e.g., the Piltdown Man fossil or unidentified flying objects) and that the theory is sometimes wrong (e.g., the Ptolemaic model of the movement of the Sun, Moon, and planets).

The Scientific Method

Test the Hypothesis

Formulate a Hypothesis

Ask QuestionsMake

Observations

Design Experiment

Collect Data

Analyze the Data

Draw Your Conclusions

Measurements

Calculations, Graphs, Tables

Possible Explanations

Measure-ment

Units Units (abbrev.)

How we measure it

Length meters, centimeters, feet,

inches, miles

m, cm, km, ft, in,

mi

Ruler, measuring

tapeTime seconds, minutes,

hours, days, yearss, min,

hr, dy, yrClock,

stopwatchMass grams, kilograms,

pounds, ouncesg, kg, lb,

ozScale, triple

beam balance

Measure-ment

Units Units (abbrev.)

How we measure it

Volume milliliters, liters, cubic centimeters, cubic feet, gallons

mL, L, cm3, ft3,

gal

graduated cylinder

Temper-ature

degrees Celsius, degrees

Fahrenheit, Kelvin

°C, °F, K thermo-meter

Measuring Volume

Graduated Cylinders

Measure from the bottom of the meniscus (U-shape).

What is the volume of liquid in this graduated cylinder?

What is the volume of liquid in this graduated cylinder?

1 Notch below 800 mL, so…

about 790 mL

More Experiment Vocabulary

More Experiment Vocabulary

Converting Between Units(the Chemistry way)

• Even if you can do the conversion in your head or by only using a calculator, you need to practice following the steps.

• Eventually the problems in this Chemistry class will become too complicated to do without writing out the steps.

• You can still use a calculator, just save it for the last step.

• You will only get full credit for these questions by showing your work. You will get partial credit even if you got the wrong answer if you followed the steps.

Converting Between Units

? ft 10 in

1 ft = 12 in

Example #1: Convert 10 inches to feet.

Step 1) Put what you are starting with over 1.

1

Converting Between Units

? ft 10 in

1 ft = 12 in

Example #1: Convert 10 inches to feet.

Multiply it by the conversion factor as a fraction. Put the units that you are getting rid of on the bottom. Put the units you want on the top.

1 12 in1 ft×

Step 2)

Converting Between Units

? ft 10 in

1 ft = 12 in

Example #1: Convert 10 inches to feet.

Cancel out the units that are on both the top and bottom.

1 12 in1 ft×

Step 3)

Converting Between Units

? ft 10 in

1 ft = 12 in

Example #1: Convert 10 inches to feet.

Multiply everything on the top. Multiply everything on the bottom. Keep the units that have not been cancelled out.

1 12 in1 ft× 12

10= ft

Step 4)

Converting Between Units

? ft 10 in

1 ft = 12 in

Example #1: Convert 10 inches to feet.

Divide the top by the bottom with a calculator to get a decimal.

1 12 in1 ft× = 0.83 ft12

10= ft

Step 5)

Converting Between Units

? L 2.5 gal

1 gal = 3.8 L

Example #2: Convert 2.5 gallons to liters.

Put what you are starting with over 1.

1

Step 1)

Converting Between Units

? L 2.5 gal

1 gal = 3.8 L

Example #2: Convert 2.5 gallons to liters.

Multiply it by the conversion factor as a fraction. Put the units that you are getting rid of on the bottom. Put the units you want on the top.

1 1 gal3.8 L×

Step 2)

Converting Between Units

? L 2.5 gal

1 gal = 3.8 L

Example #2: Convert 2.5 gallons to liters.

Cancel out the units that are on both the top and bottom.

1 1 gal3.8 L×

Step 3)

Converting Between Units

? L 2.5 gal

1 gal = 3.8 L

Example #2: Convert 2.5 gallons to liters.

Multiply everything on the top. Multiply everything on the bottom. Keep the units that have not been cancelled out.

1 1 gal3.8 L× = 9.5 L

Step 4)

Converting Between Units

? ft 78 cm

1 ft = 12 in 1 in = 2.5 cm

Example #1: Convert 78 centimeters to feet.

Put what you are starting with over 1.

1

Step 1)

Converting Between Units

? ft 78 cm

1 ft = 12 in 1 in = 2.5 cm

Example #3: Convert 78 centimeters to feet.

Multiply it by the 1st conversion factor as a fraction. Put the units that you are getting rid of on the bottom. Put the units you want on the top.

1 2.5 cm1 in×

Step 2)

Converting Between Units

? ft 78 cm

1 ft = 12 in 1 in = 2.5 cm

Example #3: Convert 78 centimeters to feet.

Cancel out the units that are on both the top and bottom.

1 2.5 cm1 in×

Step 3)

Converting Between Units

? ft 78 cm

1 ft = 12 in 1 in = 2.5 cm

Example #3: Convert 78 centimeters to feet.

Multiply it by the 2nd conversion factor as a fraction. Put the units that you are getting rid of on the bottom. Put the units you want on the top.

1 2.5 cm1 in×

Step 4)

12 in1 ft×

Converting Between Units

? ft 78 cm

1 ft = 12 in 1 in = 2.5 cm

Example #3: Convert 78 centimeters to feet.

Cancel out the units that are on both the top and bottom.

1 2.5 cm1 in×

Step 5)

12 in1 ft×

Converting Between Units

? ft 78 cm

1 ft = 12 in 1 in = 2.5 cm

Example #3: Convert 78 centimeters to feet.

Multiply everything on the top. Multiply everything on the bottom. Keep the units that have not been cancelled out.

1 2.5 cm1 in× 30

78= ft

Step 6)

12 in1 ft×

Converting Between Units

? ft 78 cm

1 ft = 12 in 1 in = 2.5 cm

Example #3: Convert 78 centimeters to feet.

Divide the top by the bottom with a calculator to get a decimal.

1 2.5 cm1 in× = 2.6 ft30

78= ft

Step 7)

12 in1 ft×