Based on your understanding of color's relationship to wavelength, identify the approximate wavelength of light (nm) emitted by strontium when it was burned in Part C. (No quantitative data was collected for this; you are giving an approximate value only, based on what you observed.) Explain your reasoning in full, making sure to cite specific data and observations to support your answer.

The flame colour of strontium is red. Red has a wavelength of around 620 to 750 nm.

Explanation:

Visible light is part of the electromagnetic spectrum. The electromagnetic waves are composed of electric and magnetic fields.

The visible spectrum is composed of seven different wavelengths that corresponds to different colours. When a metallic element is exposed flame, one of these colours is observed. This is commonly called the flame test.

The flame colour of strontium is red. Red has a wavelength of around 620 to 750 nm.

1. the question asks the most appropriate, which seems to rule out "all of the above." your choice appears to be the correct one.

2. the protocol described is good for identifying correlation, but not cause and effect. for cause/effect, you need to devise a protocol that will assign the treatment (or not) to groups that have essentially the same "demographics" with respect to all the other variables. your choice regarding control group seems appropriate. random assignment of treatment (choice d) may be appropriate also. (i think you can argue that b and d are just different descriptions of the same method.)

3. d will randomize the birds, but may not guarantee there are 10 in each group. e will do both, so seems the better choice.

comment on question 2

based on the problem statement, it seems clear that confident, attentive drivers are more likely to use daytime running lights. so, the protocol might need to be devised in such a way that the lights would be turned on or off without the driver's knowledge. (an attentive driver will figure it out.) assigning a confident, attentive driver to a group required to drive without running lights might mess with his/her confidence and attentiveness. you don't want your experiment to do that. (nor do you want the experiment to subject a driver to greater risk of accident as a consequence of driving without running lights.) experiments involving human safety are always problematic.

in cartography, a contour line (often just called a "contour") joins points of equal elevation (height) above a given level, such as mean sea level. a contour map is a map illustrated with contour lines, for example a topographic map, which thus shows valleys and hills, and the steepness or gentleness of slopes.

explanation: