Transcript QOD—Monday, August 29

QOD—Monday, August 29
•
A)
B)
C)
D)
Tell which statements describe a
hypothesis. (may be more than one
answer—choose all that apply)
It is the result of many experiments
It is a possible answer to a question
It is a question
It can be tested by experimentation or
observation.
Answer
• B and D are qualities of a hypothesis.
• A) a hypothesis is made before the
experiments and directs the type of
experiments done.
• C) a posed question may LEAD to a
hypothesis to test.
Answers to HW
1. Mass: solid food items, people, and mail;
Volume: liquid food items and gasoline;
Length: rope, distance, height
Answer to HW #2
2. The scientific method involves critical
thinking in that it entails thinking about a
problem and making objective judgments
about results.
HW Answer #3
3. A hypothesis is a possible answer to a
question that can be tested. An example
would be, “I can pass the test if I study at
least 5 hours.”
HW Answer #4
4. No experiment should be called a failure
because an experiment that produces
unexpected results provides a chance to
learn something new.
HW Answer #5
• There are still scientific theories that have
not been verified, because the tools needed
to test these theories do not yet exist.
HW Answer #6
6. An SI-based unit is a single unit while a
derived unit is a combination of base units.
Base units include: seconds, meters,
kilograms, Kelvin, amperes, moles and
candelas. Examples of derived units
include meters squared (m2) or meters
cubed (m3).
HW Answer #7
7. It is much easier to determine which factor
your experiment depends on if you only
check one factor at a time. If you change
more than one thing and something
unexpected happens, you will not know
what caused the result.
QOD Tuesday, August 30
Which statements are hypotheses? EXPLAIN your
answer(s).
A) Cockroaches are repelled by cucumber slices.
B) Leos are luckier than Capricorns
C) Ajax beige wall paint fades more quickly than
Supreme beige wall paint
D) Newton was the greatest 18th century scientist.
Answers
• A and C can be tested by established
scientific methods.
• B cannot be tested.
• D is an opinion.
QOD
• How do scientists report their results and
conclusions to other scientists?
• Scientists can share information by
publishing articles in scientific journals, by
giving oral or visual presentations at science
meetings, and by using the Internet.
1. Describe the kind of data that
is best displayed in a line graph?
• Line graphs are best for continuous change.
2. Describe the kind of data that
is best displayed as a pie chart.
Give example
Answer: Pie charts show the parts of a whole.
An example is the percentages of types of
CDs that make up a collection.
3. Explain in your own words
the difference between accuracy
and precision
Answer: Accuracy is how close a
measurement is to being correct. Precision
indicates the reproducibility of the
measurements or how close the
measurements are to each other. Precision
can also show how many decimal places
were in the measurement.
4. Critical Thinking: An old riddle asks,
Which weighs more, a pound of feathers
or a pound of lead?
Answer: The correct answer is that both
weigh the same. A reason for an incorrect
answer might be that mass is confused with
volume, and a given volume of feathers
would be much lighter than the same
volume of lead.
5. Convert the following
measurements to scientific notation
a) 15, 400 mm3
1.54 x 10 4 mm3
b) 0.000 33 kg
3.3 x 10-4 kg
c) 2050 mL
2.05 x 103 mL
d) 0.000 015 mol
1.5 x 10-5 mol
6. Calculate the following:
3
4
a) 3.16 x 10 m x 2.91 x 10 m =
9.2 x 107 m2
b) 1.85 x 10-3 cm x 5.22 x 10-2
cm =
9.66 x 10-5 cm2
c) 9.04 x 105 g / 1.35 x 105 cm3 =
6.70 g/cm3
7. Calculate the following and
round to the correct number of
sig figs.
a) 54.2 cm2 x 22 cm =
3
1,200 cm
b) 23,500 m / 89 s =
260 m/s