General Science Module 3

Question 1

1.a)Experimental Variable

Answer 1

An aspect of an experiment that changes over the course of the experiment

Question 2

1.b)Control (of an experiment)

Answer 2

The variable or part of the experiment to which all others will be compared

Question 3

1.c)Blind Experiments

Answer 3

Experiments in which the PARTICIPANTS do not know whether or not they are part of the control group

Question 4

1.d)Double-Blind Experiments

Answer 4

Experiments in which neither the PARTICIPANTS OR THE PEOPLE ANALYZING the results know who is in the control group.

Question 5

2)When is an experimental variable good and when should it be reduced or eliminated?

Answer 5

An experimental variable is good when you are using it to learn something from the experiment, And should be reduced or eliminated when it effects the results of the experiment.

Question 6

’s 3-7 refer to the story on the back of the card.

Answer 6

A consumer lab decides to test the effectiveness of diff. laundry detergents. 5 white shirts are stained with grass stains & put into 5 washers. In 1 washer, no detergent is used. In the other 4, 4 diff. types of detergent are used.water from the same source is used to fill each. They are then turned on to the same time & same cycle. Then the shirts are examined to see which is cleanest.

Question 7

3) What is the control for the shirt experiment?

Answer 7

The shirt being washed w/ no detergent.

Question 8

4) What is the experimental variable that will be used to learn something from the experiment?

Answer 8

The type of detergent used

Question 9

5) Which variables need to be reduced or eliminated?

Answer 9

– The washers are different

Question 10

6) What could be done to reduce or eliminate the variables?

Answer 10

– The 1st can be eliminated by making sure all washers are the same model, brand and age

Question 11

7) Are the data collected objective or subjective?

Answer 11

Subjective

Question 12

8) Why can a carefully place needle float on water, even though it is denser than water?

Answer 12

Because of Surface Tension

Question 13

9) What does soap do to water’s Surface Tension?

Answer 13

soap reduces the surface tension of water

Question 14

10) When a student compares the surface tension of liquids by laying a needle gently on water and another liquid, he find it easier to lay it on the other liquid. Why?

Answer 14

Because the other liquid must have a larger surface tension than water.

Question 15

11) A month after a new, fat free potato chip comes out on the market, reports come in that the chips cause severe stomach aches. You must do an experiment to see if it is true. A group of people volunteer for the study. Describe how you would design the experiment, and describe whether it should be single-blind, double-blind, or neither.

Answer 15

You would give half of your volunteers the new chips, and half regular chips that have been on the market for years. The volunteers can then keep a log for the next couple of hours to see if any stomach aches occur. the experiment should be double blind.

Question 16

12) A study is done to see if a certain herb effects student’s concentration skills. Half of the student volunteers are given the herb-pill, and half are given a sugar-pill placebo. should this be a single, or double blind experiment?

Answer 16

This should be a single-blind experiment.

Question 17

13) A farmer has been asked by the government to experiment w/ different herbicides. he sprays a different herbicide on 3 fields and leave a 4th one to grow normal. after harvest, he reports to the govt his results. should this be single-blind, double-blind, or neither?

Answer 17

Neither

Question 18

14) While studying the behavioral differences in home schooled and publicly schooled children, a researcher gathers a few students from each group and observes how they play together. should this be single-blind, double-blind, or neither?

Answer 18

Double-Blind

Question 19

15) A scientist invents a new “weight loss w/o dieting” pill and use two groups to test it. to 1 group he gives the pill, and to another he gives a placebo. he then observes them for twelve weeks. should this be single, double or neither-blind?

Answer 19

single-blind

Question 20

A student is playing with a spring and notices that the more a he weight he hangs on it, the more it stretches. He suspends the spring from the ceiling and puts a hanger at the bottom of the spring. Then he starts putting more weight on the hanger, and come up with the graph on the other side.

Answer 20

…

Question 21

16) How long is the spring when it is not stretched out at all?

Answer 21

5 in.

Question 22

17) How many pounds are necessary to stretch the spring to 8 inches?

Answer 22

6 lbs.

Question 23

18) At bout what weight does the spring no longer stretch in response to no more weight being put on it?

Answer 23

The spring stops stretching after about 15 pounds.

Question 24

19) If the student repeats the experiment on many more springs, though the actual numbers vary from spring to spring, the graph would keep the same basic shape. what does this tell you about the the ability of a spring to stretch when pulled?

Answer 24

springs stretch in response to a pull, but there is some maximum strength at which they simply no longer stretch.