Ch 1.3 Scientific

MethodsInvestigation & Experimentation Standards1: a, b, c, d, e & g, j, k, l, & n

Scientific progress is made by asking meaningful questions and conducting carefulinvestigations. As a basis for understanding this concept and addressing the contentstudents should develop their own questions and performinvestigations. Students will:

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

b. analyze relationships, and display data.c. Identify and communicate sources of

unavoidable experimental error.d. Identify possible reasons for inconsistent

results, such as sources of error or uncontrolled conditions.

e. Formulate explanations by using logic and evidence.

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

g. Distinguish between hypothesis and theory as scientific terms.

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

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).

Scientific Inquiry… a search for information and explanation often focusing on specific questions.

TWO MAIN FORMS OF INQUIRY:

1. Discovery Science

describes natural structures and processes as accurately as possible through careful observation and analysis of data. Conclusions based on logic… “inductive reasoning”. Ex. microscope observations led to the CELL THEORY

2. Hypothesis-Based Science

Process of inquiry that includes repeatable observations and testable hypotheses… “deductive reasoning” if… then statement. Science “to know” is limited to those structures and processes we

can observe and measure. Science can not answer questions like

“Why are we here?” … this is why the humanities are so important.

Applying hypothetico-deductive reasoning to a campground problem

Steps of the Scientific Method1. Observation- use senses to perceive object or events

2. Ask Questions-

3. Collect & organize data- longest phase of investigation use specific tools ex. microscope to observe directly or indirectly

(voltmeter) quantitative (measured in numbers) Sampling (a small part represents an entire population)

4. Hypothesize- a testable explanation that explains the observations and predicts the outcome

1. Prediction posed as “if___ then___” statement. 2. Inferences use logic and prior knowledge to make sense of the

data collected and predict the result of a well-designed experiment.

5. Experiment- testing a hypothesis under controlled conditions- comparison between control group & experimental group

6. Draw conclusions

7. Ask new questions

8. Design new experiment (repeat & refine)

How to write a Lab Report:(this mirrors the scientific method )

1. Title

2. Introduction (observations, background info, purpose of experiment)

3. Hypothesis (is a prediction)

4. Materials & Methods (explain the experiment)

5. Results (tables, graphs- quantitative/qualitative)

6. Discussion (analysis of results, misatkes?, conclusion, next experiment)

What are the elements of an excellent experiment???

What are the elements of an excellent experiment???

1. Control the variables (variables are any factors influencing the results of your experiment- keep them CONSTANT).

2. Have a large sample size of test subjects &/OR repeat your experiment to counter unavoidable experimental error.

3. Have a control group to compare your experimental group to so you see magnitude of the results.

4. Change only ONE variable between these groups while holding all others constant. =‘s the INDEPENDENT VARIABLE

5. Obtain quantitative data (when possible) and use appropriate tools for measurement

Ex. pH meter, volt meter, microscope, ruler, scale, geiger counter.

6. Organize collected data- measured results = DEPENDENT VARIABLE in a data table then show as a graph.

A controlled experiment is a comparison of two or more groups with only one

difference in variables between the groups when you set up your experiment.

CONTROL GROUP EXPERIMENTAL GROUP

1. Soil2. Sunlight3. H2O4. CO25. O26. Real trees

1. Soil2. Sunlight3. H2O4. CO25. O26. Artificial trees

The difference between the groups is called the INDEPENDENT VARIABLE

IT IS THE AGENT OF CAUSE IN YOUR EXPERIMENT

The difference between your control group and experimental group(s).

What you are testing.

Plotted along the X-axis

Ex. artificial plant

Now you can run a great experiment!!!

But how will you know the results???

The measured result of your experiment is the DEPENDENT VARIABLE

THE EFFECT OF YOUR EXPERIMENT

The observable result of your experiment.

Plotted on the Y-axis.

Dependent variables are caused by the independent variable.

You take some sort of measurement and record it.

Ex. stem height in centimeters

TITLE: A comparison of a car’s value related to its’ mileage

(miles)

(dollars)

X axis

Y axis

When is a line graph appropriate?

When is a bar graph appropriate???

What’s the deal with this double bar graph?

Why the pie chart?

Display parts of a whole.

ANALYSIS

• ANALYSIS:• What were the results and what do

they mean?• Was data good or bad?• Were mistakes made?• Make a conclusion- does the data

support or refute the hypothesis? What if neither??? Inconclusive…

• What should be done next? Design your next experiment.

DRAWING CONCLUSIONS1. INFERENCE- a conclusion made on the collection of facts not on direct

observations. = hypothesis

ie. Owl pellets let you know what it ate.

2. MODEL- explanation supported by data.

ie. Atom structure or structure of the universe

3. LAW- analytical statement empirically provable using math- has a constant. Considered universal and invariable facts.

ie. Gas Laws, Kepler’s Laws of Planetary Motion, Law of Conservation of Energy, Newton’s Law of Universal Gravity

3. THEORY- broad, comprehensive statement of what is thought to be true.

*few theories exist…they are supported by tremendous amounts of evidence… ties together several related hypothesis and may incorporate one or more laws.

ie. Relativity, Natural Selection, Germ Theory

Theories can be proven wrong, so can Laws.

www.toptenz.net/top-10-most-famous-scientific-theories-that-turned-out-to-be-wrong.php

a. Select and use appropriate tools and technology (such as computer-linked probes-pH meter, 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. Distinguish between hypothesis and theory as

scientific terms.g. Recognize the usefulness and limitations of models

and theories as scientific representations of reality.

Standards 1 a, b, c, d, e & g

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.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).

Standards 1 j, k, l, & n

THE FIRE LAB: answers

PART I: #1-3

Light emitted from candle, flame moving

Orange flame on match

Blue flame toward wick of candle

Flame moves w/ air.

Wick is black.

PART II: #1 & 2

Match burns shorter/ temperature is hotter

The ignition of match is more volatile

Candle burns longer/ temperature is not as hot.

Flame is pale on candle and darker (more orange) on the match.

#3 & 4

Birthday candle flame taller, brighter burning, burns more quickly, wax can drip down.

Votive candle has a shorter flame as the wax can’t escape and pools at base of wick.

The higher the surface area, lower burning (wax is contained) = slows the burning process, less wick exposed.

Black around the wick is CARBON.

#5

Beaker: flame to the bottom of the beaker: glass turns black.

#8

Physical & Chemical change difference is that the molecules remain the same just change their state of matter (solid, liquid, gas) where as a chemical change breaks bonds and forms new bonds creating new molecules.

Black soot is carbon = chemical change of the wax.

the wax from solid to liquid to gas = physical change

#9

Oxidation = burning sugar in our bodies to get energy.

Cell respiration (in mitochondria)

PART III: 1 a-d & 2 OBSERVATIONS

Flame gets smaller and flame goes out

Water rises in the beaker (higher than level outside the beaker.)

INFERENCES/HYPOTHESIS

Heat up the gas molecules and the gases expand.

Flame goes out when there is no oxygen left.

When the flame goes out the molecules cool down and contract pulling water into the glass beaker.

LIGHT TWO CANDLES

Will happen faster??? Two flames use up the oxygen faster.

HOW TO VIEW A FLAME…

More complete burn of gas (flame turns blue) releases the most heat.

More incomplete burn of gas (flame turns orange/yellow) is good for giving off light.

Carbon monoxide, which is toxic, is given off w/ an incomplete burn. SCARY.

PART IV

#2

1) Wax + O2 -> CO2 + H2O + Energy (FULL BURN)

Blue flame = most complete burn… means more oxygen getting in (at bottom).

2) Wax + O2 -> CO + H2O + Energy (MIDDLE burn)

Orange or dark part of flame in the middle

3) Wax + O2 -> C + H2O + Energy (most incomplete)

Smoky part of flame at top

#2: What is the significance of this information????

Candles used to see (light energy) orange/yellow.

Burning for heating energy- blue… more complete burn.

Burning sugar in your body…

OXIDATION = energy formation in our bodies- sugar is burning to make energy. This is why you need oxygen to live!!!!

Steps of the Scientific Method

1. Observation- use senses to perceive object or events.

2. Ask Questions

3. Collect & organize data- sample or quantitative

4. Hypothesize- a testable explanation

5. Experiment- testing a hypothesis under controlled conditions

6. Draw conclusions

7. Ask new questions

8. Design new experiment

MOUTHWASH LAB

Observations:

People have stinky breath

People use “mouthwash” to prevent bad breath and to keep their teeth healthy.

Ask Questions:

What is making their mouths stinky? What are you protecting teeth from?

Which mouthwash brand is the best one? Cost, ingredients, packaging, endorsements

3. Collect and organize data

1. Bacteria cause the bad breath and tooth decay.

• Are: single-celled, prokaryotic, micro-organisms that reproduce by binary fission.

• 1st life forms that evolved 3.5 billion years ago

• Ex. One bacterium can reproduce every 20 minutes. Thus millions can exist from the reproduction of just one with in 24 hours.

• Some are good, some cause tooth decay (secrete acids that are corrosive to enamel).

• Their dying bodies and waste products they secrete are what make your mouth stink.

Bacteria are alive. Need water and nutrients to grow. Reproduce by

Binary Fission to form Colonies that are visible w/out a microscope.

BINARY FISSION

PETRI DISH WITH NUTRIENT AGARSHOWING SEVERAL DIFFERENT BACTERIAL COLONIES

MOUTHWASH INFORMATION

Target Scope $2.09 Crest Blue $4.19 Listerine Purple

$3.44 Listerine Yellow

$3.99

You might want to check the ingredients yourself.

Define mouthwash.

HYPOTHESIS

Based on the collected information, create not only your best guess for which one is best- but create it as an if then statement.

I predict that _______ is the best mouthwash. If it is then ________ will happen.

DESIGN YOUR EXPERIMENT Do this today.

Conduct the experiment today. Draw exactly what your petri dish looks like today and mark the exact time and date.

We’ll check the results next week.

MATERIALS AVAILABLE TO EACH GROUP OF 4:

Petri dish with nutrient agar (it is delicate, don’t break the agar when spreading your bacteria on the plate.)

1 Q-Tip (to get your bacteria sample)

1 sharpie marker (to write on your petri dish)

Paper soaked in various mouthwash brands & water.

Forceps (tweezers) for moving the paper discs soaked in solutions.

Parafilm to seal the petri dish lid to the plate.

RESULTS

NEXT CLASS WE WILL LOOK FOR AND MEASURE the absence of BACTERIAL COLONIES.

RING OF INHIBITION- forcefield / break in the lawn.

Ring of Inhibition=Dependent variable