2016 Mod3

Question 1

Define the following terms:

A. Experimental variable

Answer 1

A. An aspect of an experiment that changes during the course of the experiment

Question 2

When is an experimental variable good and when should it really reduced or eliminated?

Answer 2

When you learn something/was planned for

Question 3

Questions three through seven referred to the following story:

Answer 3

A consumer laboratory decides to test the effectiveness of different laundry detergent. Five white shirt are stained with grass stains and put into 5 different washers. In one washer, no laundry detergent is used. In the other four washers, four different types of laundry detergent are used, one type in each washer. Water from the same source is used to fill each washer. The washers are then turned on for the same amount of time and the same kind of cycle, and once they’re finished, the shirts are examined by eye to see which is the cleanest

Question 4

What was the control for this experiment?

Answer 4

The one without laundry detergent

Question 5

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

Answer 5

The different kinds of laundry detergent

Question 6

What are the experimental variable that need to be reduced or eliminated?

Answer 6

The different amounts of stains and laundry detergent used

Question 7

Was it could be done to reduce or lemonade the unwanted experimental variables?

Answer 7

They could measure the soap, and stain the shirt the same amount

Question 8

Are the data collected objective or subjective

Answer 8

Objective

Question 9

Why can a carefully placed needle float on water, even though a needle is denser than water

Answer 9

Because of surface tension

Question 10

What does soap do to the surface tension of water?

Answer 10

soap reduces it

Question 11

A student tries it float a needle on water. He succeeds, but only after several attempts. He then tries to float the same needle on another liquid. Although the needle sink when dropped into the liquid, it is much easier to lay the needle on the surface of the liquid and make it float then it was to get the needle the float on water. Compare the surface tension of this liquid to the surface tension of water.

Answer 11

The surface tension was greater in the other liquid than that which is on water

Question 12

A new, fat free potato chip comes out on the market. I few months later, there are reports that some people get severe stomach cramps a few hours after eating the chips. You must do an experiment to see if the chips cause severe stomach cramps. A group of people volunteer for the study. Describe how you would design the experiment. Also, indicate whether the experiment should be a single blind, double blind, or neither

Answer 12

It should be double blind. I would have two groups of people. They would not know if they were in the control group or not.Half would eat the new potato chips and half would eat the regular then I would have them write down what happened in a few hours then I would take the reports and give them to someone who knows who’s in the control group and who’s actually eating the new potato chips

Question 13

A study is done to see if a certain herb can increase a student’s concentration skills. A group of students volunteer for the experiment, which consists of giving the students a pill made of either sugar or the herb. The students then take a series of math test. The test scores of the student who take their herb will be compared to those who took the sugar pills. If there is a difference between the average test scores of the group, it could very well be the result of the herb. Should this be a single blind-experience, a double-blind experiment, or neither?

Answer 13

Double-blind

Question 14

A farmer has four different cornfields. The government pays him to experiment with three different kinds of herbicides (weed killers). He sprays nothing on one field, and he sprays each of the other field with a different brand of herbicides. He then records the number of tons a corn he produces from each field, and report back to the government about which herbicides produce the best crop. Should this be a single-blind experiment a double-blind experiment,or neither

Answer 14

Neither

Question 15

A researcher is trying to determine if there are any differences between how homeschooled students play and how publicly school student play. She plans to get a publicly school students and a group of homeschooled student together and observe how the children play with one another. She will record her observation and then try to see if the ways in which the homeschooled children play with the other are different from the ways in which publicly school children play with each other. should this be a single blind experiment, a double-blind experiment, or neither

Answer 15

Double-blind experiment

Question 16

A scientist comes up with a revolutionary drug that he thinks will allow people to lose weight without dieting. They simply need to take the pill, and their excess weight will slowly disappear. He decides to test the pill by getting two groups of volunteers together. The first group will take the fake pill, and the second group will take his new drug. Each volunteer will be weighed once a week for 12 weeks. Should this be a single blind experiment, a double-blind experiment, or neither? What results will indicate that the new drug is effective?

Answer 16

A single-blind experiment.

If the people who are taking the drug lose weight.

Question 17

Question 16 through 19 referred to the following story

Answer 17

A student is playing with a spring and notices that the more weight that he hangs on it, the more it stretches. He therefore decides to do an experiment. He suspends the spring from the ceiling and put a hanger on the bottom of the spring. He then start weighing more and more weight on the hanger. He measured the length of the spring each time he adds weight, and he comes up with the following graph.

Question 18

How long is the spring when it’s not stretched out at all

Answer 18

5 inches

Question 19

How many pounds are necessary to stretch the Spring to 8 inches

Answer 19

6 pounds

Question 20

At about what weight does the spring no longer stretch in response to more weight being put on it

Answer 20

16 pounds

Question 21

The student does this experiment on several more springs. Although the actual numbers vary from spring to spring, the graph always had the same basic shape. What does this tell you about the ability of a spring to stretch when pulled?

Answer 21

It can only stretch so far

Question 22

B. Control (of an experiment)

Answer 22

B. Variable or part of the experiment to which all others will be compared.

Question 23

C. Blind experiments

Answer 23

C. Experiment in which The participants do not know whether or not they are part of the control group

Question 24

D. double-blind experiments

Answer 24

D. Experiments in which the participants nor in the people analyzing the results know who is in the control group