Thursday
December 18, 2014

Homework Help: Science

Posted by thewhat on Thursday, October 31, 2013 at 11:17am.

1.
Why do scientists use models of natural systems? (1 point)

Scientists use models of natural systems because these systems are often too large, too small, or too complex to study directly.
Scientists use models of natural systems because they like to use art in science.
Scientists use models of natural systems because the models are more accurate than the actual system.
Scientists use models of natural systems because models work exactly the way these systems do in nature.

2.
A scientist is studying a new chemical he hopes will prevent insects from eating raspberry bushes. He sprays the chemical on a raspberry bush and places it with an unsprayed blackberry bush and some insects in a sealed room. He observes insects eating the blackberry bush, but not the raspberry bush. He concludes that the chemical works. This situation is an example of (1 point)

a controlled experiment.
experimental bias.
cultural bias.
skepticism.

3.
Why do scientists use the International System of Units (SI)? (1 point)

because the SI is based on the metric system
because the tools scientists use only measure in SI units
so they can communicate their results without confusion
so all scientists are guaranteed to come up with the same measurements

4.
What should you do if there is an accident while you are doing a scientific investigation? (1 point)

Go to the hospital.
Wait a few minutes to see if you are hurt or there is any damage to your work station.
Call 911.
Tell an adult immediately and follow his or her directions as quickly as possible.


7.
A student measures a rectangular room to be 20.0 m ◊ 17.16 m. Which of the numbers below represents the roomís area with the correct number of significant figures? (1 point)

340 m2
343 m2
343.2 m2
343.20 m2

8.
A student measures the mass of a paper clip. The studentís data table is shown below. The accepted value for the paper clipís mass is 1.14 g.
Trial # Mass
1 2.45 g
2 2.40 g
3 2.42 g

Which of the following best describes the studentís measurements? (1 point)

The studentís measurements were accurate, but not precise.
The studentís measurements were precise, but not accurate.
The studentís measurements were neither accurate nor precise.
The studentís measurements were both accurate and precise.

9.
Which component of the technological system is achieved when an automobile airbag inflates? (1 point)

input
feedback
process
output

11.
How can surveying reading material improve your comprehension? (1 point)

Knowing the main ideas ahead of time helps you know where to focus your attention.
Reciting the answers to questions out loud will help you remember them.
Reading ahead makes studying go faster.
Surveying ahead of time means you can skip maps, diagrams, and content summaries later.

12.
An advertisement claims that three out of five dentists prefer a particular type of toothpaste. After researching the study, you find that the toothpaste company paid for it. Why should you be skeptical of the advertisementís claims? (1 point)

because the dentists are showing experimental bias
because only dentists were involved in the study
because the organization that paid for the study is biased
because you do not like the toothpaste being advertised

13.
If a bowling ball were moved from Earth to the moon, how would its weight and mass change? (1 point)

The bowling ball would weigh the same, but its mass would increase.
The bowling ball would weigh the same, but its mass would decrease.
The bowling ball would weigh less on the moon, but its mass would stay the same.
The bowling ball would weigh more on the moon, but its mass would stay the same.

14.
A student hypothesizes that a goldfish will be more active in a bowl that has red gravel than in a bowl with grey gravel. To test this hypothesis, the student places one goldfish in a bowl with red gravel and another goldfish in a bowl with grey gravel. The color of the gravel is the _______________ variable in the experiment. (1 point)

control
responding
dependent
independent


15.
A scientist goes to a large international conference and hears about a new discovery. The scientist is very excited about these new findings and decides to verify the other scientistsí results by conducting her own investigations. The scientist is being open-minded but __________________. (1 point)

16.
A scientist observes chimps putting dry leaves into a hole in the tree. The leaves come out wet and the chimps lick the water off of the leaves. The scientist reasons that there is water inside the tree. This reasoning is called a(n) ________________. (1 point)

17.
Contact lenses improve lives. Contact lenses are an example of a(n) ________________. (1 point)



my answers
1.a
2.b
3.c
4.d
7.d?
8.b
9.b
11.a
12.c
13.c
14.d
15.cautious or skeptical?
16.inference?
17.technology.

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