Scientific Method * Conducting an investigation

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Transcript Scientific Method * Conducting an investigation

 Oil
Eating Bacteria #1-2
 Write
a response to the following prompt.
Your response must be more than one
sentence and it can’t include “I DON’T
KNOW” (IDK)
Why do we trust that Scientists
have correct explanations for
how things work?
Science is a way of learning about the natural
world. Science also includes all the knowledge
gained from exploring the natural world.
Scientists use skills such as observing, inferring, and predicting to
learn more about the world.

Observing means to use your senses (sight, hearing, touch,
taste, or smell) to gather information.

When you explain or interpret the things you observe, you are
inferring, or making an inference.
 based on prior knowledge, experiences, and observations

Predicting means making a forecast of what will happen in the
future based on past experience or evidence.
Take
5-7 minutes to
read Thinking Like a
Scientist. Underline or
highlight any unfamiliar
words. Be ready to
discuss.
Successful scientists possess important attitudes such as curiosity,
honesty, open-mindedness, and skepticism.

An important attitude that drives scientists is their curiosity.
Successful scientists are eager to learn.

Good scientists are honest. They always report their
observations and results truthfully.

Scientists need to be open-minded, or capable of accepting new
and different ideas.

Open-mindedness should always be balanced by skepticism,
which is having an attitude of doubt.
 Example
1 - you hear a whistling
sound outside (observation) and say
it is a bird (inference). Of course, it
may have been a tape of a bird! Or a
Space Alien!
 Example 2 - you see an unusual light
in the sky (observation) and say it is
an Alien Spacecraft (Inference)
1.
2.
3.
4.
5.
6.
Are there cars parked on the side
of the road?
What color is the pickup truck
driving in the road?
Any minivans around?
What does the blue sign say?
What is the speed limit?
Are there any pedestrians on the
road?
A means of acquiring knowledge scientifically; the
system of advancing knowledge by formulating a
question, collecting data about it through
observation and experiment, and testing a
hypothetical answer.
 Question
 Research
 Hypothesis
 Experiment
 Data
analysis
 Conclusion (report
results)
 Retest
 Observations
are
gathered through
your senses
 A scientist observes
something
interesting in the
natural world
 The scientist
formulates a
question
The scientist gathers
information about the
question through
research and more
observation.
 Based
on his research, the
scientist predicts an
answer to the question
A
hypothesis is sometimes
called an educated guess
or prediction
A
hypothesis must be
testable
A
hypothesis is often
written as an “If…
Then…” statement
1.
2.
3.
Do not use I, me, my, or they (no personal
pronouns).
If possible, write the hypothesis in an “if-then”
format. (IF this happens, THEN this will happen.)
Write the hypothesis as a statement, not a
question.
Examples:
If salt is added to fresh water, then the freezing point
of the water will be lower than 0°C.
If a city is located near tectonic plate boundaries,
then the city will experience more earthquakes.
1. Practice Question:
Jared investigated chemical reactions based on smell, color
change, and release of bubbles.
What type of evidence would support any conclusion Jared
makes
A. a measurement
B. an observation
C. a calculator
D. an estimation
2.Scientific Question:
Are elephants afraid of mice?
3. Hypothesis:
Write a hypothesis predicting your answer.
An experiment is a
procedure (usually
written in steps) that
will prove or disprove
the hypothesis by
carefully using a
controlled process.
Variable – Any factor
in the experiment
that can change
An experiment is
good or “valid” if
the scientist
changes only ONE
variable at a time!
The scientist
changes one
variable and
then observes
or measures
what happens
as a result.
The variable that is
purposefully changed
in the experiment is
called the independent
variable. (should only
be one thing)
The variable that
responds to the
change is called the
dependent variable.
This is what is being
measured in the
experiment.
All other variables
must be kept exactly
the same so that they
will not affect the
outcome of the
experiment. These are
called control variables.
They are used for
comparison.
In your hypothesis:



the “if” statement
explains how the
independent variable will
be changed.
the “then” statement
explains how the
dependent variable will
most likely respond.
If the independent
variable changes, then
the dependent variable
will change.
An experiment was done to see if rotted leaves added to soil had
an effect on tomato production. One tomato plant was grown in
each of four large tubs. The following amounts of rotted leaves
were added to the tubs: Tub A had 15 kg added, Tub B had 10 kg
added, Tub C had 5 kg added, and Tub D had no rotted leaves
added. Each tub had the same type and amount of soil, got the
same amount of sunlight, and was watered the same amount. The
total mass (in kg) of tomatoes produced by each plant was
measured and recorded for three months.
What is the scientific question?
Does adding rotted leaves to soil increase
tomato production?
What is a possible hypothesis?
If rotted leaves are added to soil, then
tomato plants will produce a larger mass of
tomatoes.
An experiment was done to see if rotted leaves added to soil had
an effect on tomato production. One tomato plant was grown in
each of four large tubs. The following amounts of rotted leaves
were added to the tubs: Tub A had 15 kg added, Tub B had 10 kg
added, Tub C had 5 kg added, and Tub D had no rotted leaves
added. Each tub had the same type and amount of soil, got the
same amount of sunlight, and was watered the same amount. The
total mass (in kg) of tomatoes produced by each plant was
measured and recorded for three months.
What is the independent variable?
What is the dependent variable?
The rotted leaves
The total mass of tomatoes
produced by each plant
What are the control variables? Type and amount of soil, amount
of sunlight, amount of water,
time
James wondered if music had an effect on plant growth. To
answer the question, he placed 25 bean plants into each of two
identical greenhouses. He played music constantly in one
greenhouse and not at all in the other greenhouse. The
greenhouses were kept at the same temperature, and all plants
received the same amount of sunlight, fertilizer, and water. At the
end of two weeks, the height of all the plants was measured.
What is the independent variable?
What is the dependent variable?
What are the control variables?
What is the scientific question?
What is a possible hypothesis?




Data - Facts, figures, and other
observations gathered during an
experiment; often organized into
tables or graphs
Quantitative data comes from
observations that can be measured in
numbers or amounts (length, time,
mass, temperature, etc.)
Qualitative data comes from
observations that can’t be measured
(color, shape, taste, etc.)
Both types of data are important to
scientists!
For extra practice!
Qualitative vs. Quantitative Data
http://www.regentsprep.org/Regents/math/AL
GEBRA/AD1/qualquant.htm
http://regentsprep.org/regents/math/algebra/
ad1/dataprac.htm
A
summary of what was
learned based on the data
obtained during the
experiment. It should answer
the scientific question.
 The
conclusion may:
support the hypothesis
(accept)
or
prove it to be false
(reject)
In order to
verify the
results,
experiments
must be
REPEATED!
1)Ask a Scientific Question
2) Make Observations and do
Research about the question
3) Form a Hypothesis predicting
the answer (if…then…)
4) Design an Experiment to test
the hypothesis
5) Collect and analyze Data
6) Form a Conclusion
7) Retest
 English
System – the US is the only
industrialized nation that uses this system as
its standard measurement. (pounds,
ounces/cups, miles, Fahrenheit, etc.)
 History
– was based off of body parts and
commonly used objects.
 Drawbacks:
complex converting and same
names for different measurements such as
ounce for both weight and liquid capacity.
 Metric
(International System of Units SI)
universally used in scientific work, and widely
used around the world for personal and
commercial purposes.
 A standard set of prefixes in powers of ten
may be used to derive larger and smaller
units from the base units.
1. Practice Question:
Ethan investigated which of three liquids had the highest boiling point.
He put equal amounts of liquid in different beakers and placed each
beaker over the same amount of heat. To compare the liquids’ boiling
points, he measured how long it took for each liquid to boil.
The following table shows his results.
Amount of Time for Liquid to Boil
Liquid
Time (in seconds)
A
94
B
230
C
196
Ethan concluded that Liquid B had the highest boiling point.
Which of these led to this conclusion?
A. Quantitative measurement of how hot the liquids got
B. Qualitative observation of how long it took for the liquids to boil
C. Quantitative measurement of how long it took for the liquids to boil
D. Qualitative observation of how hot the liquids got
2. Writing Prompt:
Write the instructions for fixing a peanut butter and jelly sandwich.
Mass – unit is grams (g); used for measuring the
amount of matter in an object.
Tools used: triple beam balance, digital balance
Triple beam balance
Digital balance
 Unit
is cm3 or m3
 used
for measuring the
amount of space a solid
object takes up.
To find the volume of a
regular solid measure the
length, width, and height.
Multiply all 3 numbers
together.
 To find the volume of an
irregular solid – use the
water displacement method
(one mL equals 1 cm3)
 Ruler, graduated cylinder and
water

 Unit
– liter (L) (in
class use mainly mL)
 Used to measure
how much space a
liquid takes up.
 Tools: graduated
cylinders (most
accurate), beakers,
flasks
graduated
cylinder
beaker
flask
 Unit
– meters (m)
 Used for measuring the distance between
two points.
 Tools - rulers/meter sticks
 Unit
– Celsius (C); Celsius is based on
the freezing and boiling point of
water (0° degrees for freezing and
100° degrees for boiling). Fahrenheit
is less accurate.
 Used
to measure the movement of
molecules in a substance. The faster
the molecules are moving, the higher
the temperature.
 Tool:
Thermometer
The amount of matter in a given volume
 Density = Mass (g)/ volume (cm3)
D = M/V


Practice Problems:
1.
Rock A has a volume of 15cm3 and a mass of 45 g.
What is its density?
2.
Rock B has a volume of 30cm3 and a mass of 60g.
What is its density?
3.
Which rock is heavier? Which rock is more dense?
A golden-colored cube is handed to you. The
person wants you to buy it for $100, saying
that is solid gold. You pull out your old
geology textbook and look up gold in the
mineral table, and read that its density is 19.3
g/cm3. You measure the cube and find that it
is 2 cm on each side, and weighs 40 g.



What is its density?
Is it real gold?
Should you buy it?
1.
2.
3.
4.
5.
6.
How much matter in a calculator?
How much space dr. pepper takes up in
your drinking cup?
How much space a textbook takes up in
your book bag?
The distance from Main Hall to Math Hall?
How much space a paper clip takes up?
The height of your desk?
1.
How much matter in a calculator?
use a balance and measure in grams
2.
How much space dr. pepper takes up in your
drinking cup?
use a graduated cylinder and measure in milliliters
(mL)
3.
How much space a textbook takes up in your
book bag?
use a ruler, LxWxH, unit cm3
4.
The distance from Main Hall to Math Hall?
ruler, meters
5.
How much space a paper clip takes up?
water displacement method, cm3
6.
The height of the your desk?
ruler, centimeters (cm)
7. A scientist suspects that the amount of Vitamin A in the
diet of female mice affects the number of offspring born.
To test this idea, the scientist adds extra Vitamin A to the
food of 50 female mice for a period of two months.
Another group of 50 female mice gets no vitamin
supplements. Each mouse in the study is the same
species, gets the same amount of food and daily exercise,
and is kept at the same temperature. At the end of two
months, the total number of offspring are counted and
recorded for each group.
Which of the following is the best hypothesis? Explain why the wrong ones
are incorrect.
Female mice will eat more Vitamin A if they have more
offspring.
B. If female mice are given Vitamin A, then the number of
offspring will increase.
C. If you give mice Vitamin A, then they will have more
offspring.
D. I think the offspring number will increase if the mice are
given Vitamin A.
A.