Question: Andi and Scott decided to investigate solar water heaters using collectors of different colors (but the same size) as one variable and covered versus uncovered as a second variable. Look at the graph of their data and answer the questions below. Why would comparing only the red uncovered heater with the blue covered heater not provide useful information?
Reference answer: When 2 variables are changed, it is impossible to determine which variable is causing what effect.

Student answer: More than one manipulated variable.

Student answer: It has too many manipulated variables it could not give the same information.

Student answer: I think red reflected the heat away.

Student answer: Maybe because they are each different types.

Student answer: Because one is covered and the other is not covered.

Student answer: Because they are different colors.

Student answer: I think it is covered more than the red one. And put does too color because is almost the same.

Student answer: Because the red uncovered get colder and the blue get hotter.

Student answer: It would not be useful because red is uncovered and blue is covered and it is not fair.

Student answer: I think that the red covered was not in the sun.

Student answer: It will not be useful, because blue is covered and the heat will be trap and red is not. So all the heat will escape from the red uncover. The red uncover will heat up slow. But blue will heat up fast.

Student answer: Maybe the blue uncovered would be the same as the red or not, just to make sure.

Student answer: Because you would not know the readings of blue uncovered and red covered.

Student answer: Because both of them are different one is uncovered and another is covered.

Student answer: Because it will just be in the middle of hot and cold.

Student answer: Because.

Student answer: Because you do not have enough information to compare the data.

Student answer: Because it is only 2 colors.

Student answer: Because the red uncovered has a low temperature and blue covered has a high temperature.

Student answer: Because if they are different color and covered and uncovered you would get way different data.

Student answer: The red does not heat up fast as the blue covered.

Student answer: It would not provide useful information because you would not know if either red covered or blue covered absorbed most heat or if red uncovered or blue uncovered absorbed most heat.

Student answer: It will not be only little information and also there is not test of red covered and blue uncovered.

Student answer: It would not provide useful information because you would also need to know how much the blue heated up covered to.

Student answer: Because then you would not know if the red covered or the blue uncovered heated up as much as the others. Because even though they are the same color the water is in a different environment. So, it would not provide useful information.

Student answer: Because then you would not be controlling the variables.

Student answer: Because it did not use all the colors so they could not find out what one heated up more.

Student answer: Because they have 2 variables changed lid or no lid and color are the 2 they changed.

Student answer: It would not tell the difference if blue is warmer the red or uncover heat up slower than cover.

Student answer: Because you are comparing 2 thing and it would not make any sense because you know black heats faster than white.

Student answer: Because they are the same temperature.

Student answer: I chose that because when the plastic is darker it will heat faster than a light color.

Student answer: That will not not provide useful information because you would only know blue covered red uncovered.

Student answer: Because red uncovered is smaller than the blue covered heater.

Student answer: Uncovered versus covered would not help but both of each would.

Student answer: Because they are both covered.