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23 Multiple choice questions
Definition 1 of 23
What does soap do to the surface tension of water?
Soap causes the surface tension of water to become elastic.
Soap has no effect on the surface tension of water.
Soap increases the surface tension of water significantly.
Soap reduces the surface tension of water. water
,Definition 2 of 23
Can objective evidence be affected by opinions?
opinion determines the outcome of the experiment; like the taste of food
opinion cannot affect the experimental results; like the height of plants
opinion is the primary source of data; like a personal diary entry
opinion always affects the experimental results; like the color of the sky
, Definition 3 of 23
A consumer laboratory decides to test the effectiveness of different laundry detergents. Five white
shirts are stained with grass stains and put into five 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 same kind of cycle, and once they are finished, the shirts
are examined by eye to see which is cleanest.
What could be done to reduce or eliminate the unwanted experimental variables?
The shirt that is being washed with no laundry detergent at all is the control.
It is possible that all the detergents are so bad that they have no real effect on the cleanness
of the shirts. The only way to tell is to compare it to a shirt that was washed in no detergent.
1. The experimental variable of the washers can be reduced by making sure all washers are the
same brand and model, and by making sure they are all relatively new.
2. You can reduce the differences in water temperature by monitoring the temperature of the
water as it enters each washer and making adjustments to keep the temperature the same.
3. The experimental variable of the shirts can be reduced by making sure they are all from the
same manufacturer, the same style, and the same fabric.
4. The experimental variable of the stain can be reduced by examining each stain carefully and
trying to make sure they are all as identical as possible.
1. The washers are different. (Some can wash better than others.)
2. Water can be at different temperatures, which will effect the outcome.
3. The shirts are different. (Some fabrics are easier to clean than others.)
4. The amount of grass stain will be different on each shirt. (There is no way to stain shirts
equally.)
This should be a double-blind experiment. If the students know whether or not they are in the
control group, it might influence how they behave. In the same way, the researcher's
observations are subjective. There is no way to measure how one child plays with another. It will
depend heavily on the researcher's preconceived notions. Thus, the researcher must be as
unbiased as possible and should therefore not know who is in the control group and who is
not.
23 Multiple choice questions
Definition 1 of 23
What does soap do to the surface tension of water?
Soap causes the surface tension of water to become elastic.
Soap has no effect on the surface tension of water.
Soap increases the surface tension of water significantly.
Soap reduces the surface tension of water. water
,Definition 2 of 23
Can objective evidence be affected by opinions?
opinion determines the outcome of the experiment; like the taste of food
opinion cannot affect the experimental results; like the height of plants
opinion is the primary source of data; like a personal diary entry
opinion always affects the experimental results; like the color of the sky
, Definition 3 of 23
A consumer laboratory decides to test the effectiveness of different laundry detergents. Five white
shirts are stained with grass stains and put into five 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 same kind of cycle, and once they are finished, the shirts
are examined by eye to see which is cleanest.
What could be done to reduce or eliminate the unwanted experimental variables?
The shirt that is being washed with no laundry detergent at all is the control.
It is possible that all the detergents are so bad that they have no real effect on the cleanness
of the shirts. The only way to tell is to compare it to a shirt that was washed in no detergent.
1. The experimental variable of the washers can be reduced by making sure all washers are the
same brand and model, and by making sure they are all relatively new.
2. You can reduce the differences in water temperature by monitoring the temperature of the
water as it enters each washer and making adjustments to keep the temperature the same.
3. The experimental variable of the shirts can be reduced by making sure they are all from the
same manufacturer, the same style, and the same fabric.
4. The experimental variable of the stain can be reduced by examining each stain carefully and
trying to make sure they are all as identical as possible.
1. The washers are different. (Some can wash better than others.)
2. Water can be at different temperatures, which will effect the outcome.
3. The shirts are different. (Some fabrics are easier to clean than others.)
4. The amount of grass stain will be different on each shirt. (There is no way to stain shirts
equally.)
This should be a double-blind experiment. If the students know whether or not they are in the
control group, it might influence how they behave. In the same way, the researcher's
observations are subjective. There is no way to measure how one child plays with another. It will
depend heavily on the researcher's preconceived notions. Thus, the researcher must be as
unbiased as possible and should therefore not know who is in the control group and who is
not.
