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

More Experiment Vocabulary

hypothesis – A possible explanation of an observation.

theory – An explanation that has been repeatedly tested and accepted by most scientists.


initial observations – What we first see or notice that makes us ask questions.

control group – The group of test subjects that we keep under “normal” conditions.

experimental group – The group of test subjects that we change conditions for.


sample size – How many tests we performed.

manipulated variable – The factor in the experiment that we directly change. (aka independent variable)

responding variable – The factor that we only indirectly change. This is the “results” data that we collect from the experiment. (aka dependent variable)

NormalNormal

Normal

NormalDouble

Double

Normal Growth

Increased Growth

Decreased Growth

• Ulysses thinks skateboards are faster than scooters. In order to find out which is really faster, he decides to perform an experiment. He gets 10 kids – 5 ride skateboards; 5 ride scooters. He times how fast they do a 100 meter course.

• Samantha finds the summertime to be super hot. She thinks the fastest way to cool down is drinking ice cold water. Her sister thinks the fastest way is to drink cool water and stand in front of a fan.

• They decide to do an experiment. They have 20 people stand outside at noon for 10 minutes. Then then go inside. 10 people drink cold water and 10 people drink cool water and stand in front of a fan.

• They measure the body temperature of the 2 groups after 5 minutes of cooling off.

• Fernando notices that his dog usually scampers into his kitchen within 2 minutes of him starting to cook bacon.

• Fernando thinks that this is because his dog smells the bacon cooking, but he also wonders if his dog could be hearing the bacon sizzling or seeing him pull out the bacon from the refrigerator.

• How could Fernando design an experiment to test each one of those possibilities?

Lab Safety1. Always wear goggles, and know the location of and how to use safety equipment.

2. Minimize chemical, fire, or electrical hazards. Keep your lab area clean and clutter-free.

3. Do not run, push, or engage in any other type of potentially dangerous physical activity even if you are just joking.

4. Know what you are doing. If an accident happens, notify the teacher immediately.

Lab Safety1. Keep your lab area clean and clutter-free.

2. Be aware of smashing, tripping, burning, or electrical hazards.

3. Just like during regular class, do not run, push, or engage in any other type of potentially dangerous physical activity even if you are just joking.

4. If an accident happens, notify the teacher immediately.

Examples of Chemical Change vs. Physical Change

Burning BoilingRusting FreezingBread Rising MeltingPhotosynthesis Mixing

Salt dissolving in H2O Salt precipitating from H2O


accuracy – How close our measurements were to the real value.

precision – How close our measurements were to each other.


accuracy – How close our measurements were to the real value.

precision – How close our measurements were to each other.

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



Sig Figs1) All digits 1-9 inclusive are significant.Example: 129 has 3 significant figures.

2) Zeros between significant digits are always significant.Example: 5,007 has 4 significant figures.

3) Trailing zeros in a number are significant only if the number contains a decimal point.Example: 100.0 has 4 significant figures.100 has 1 significant figure.

Sig Figs4) Zeros in the beginning of a number whose only function is to place the decimal point are not significant.Example: 0.0025 has 2 significant figures.

5) Zeros following a decimal significant figure are significant.Example: 0.000470 has 3 significant figures.0.47000 has 5 significant figures.

Sig Figs6) When multiplying or dividing: • Find the number with the least sig figs• Calculate the answer• Round the answer to show that least

amount of sig figs.

Example: 240 × 0.5 = 120 = 100

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Investigation and Experimentation