Question

the nature of science
essential outcomes

1. describe the steps of the scientific method.
2. identify variables in a scientific investigation.
3. explain the difference between science and pseudoscience.
4. analyze & draw appropriate conclusions from a table and graph.

quick review
lets review the scientific method—by working backwards! below is a graph showing the rate of daphnia (tiny, see - through crustaceans) exposed to different water temperatures. their transparent bodies make it easy to count heartbeats under a microscope. start with the conclusion & work your way back to the beginning of the scientific method. fill in each blank using the information provided in the graph.
as the temperature __, the number of heart beats , suggesting they __.
is this data qualitative or quantitative?
heart rate (bpm)
0°c __°c °c __°c
independent variable:
dependent variable:
control group:
constant variables (2):
if
then
because they depend on external heat sources for their metabolism (they are cold - blooded or ectothermic).

Explanation:

Step1: Analyze the graph trend

As we can see from the graph, as the temperature increases from 0°C to 30°C, the number of heart - beats of Daphnia increases. Since Daphnia are cold - blooded, this suggests their metabolic rate increases.

Step2: Determine data type

The data is quantitative because we are dealing with numerical values of heart rate (number of heart beats) and temperature (in degrees Celsius).

Step3: Identify variables

The independent variable is the variable that is changed or controlled in a scientific experiment. Here, it is the water temperature. The dependent variable is the variable being measured or tested, which is the number of heart beats (heart rate). A control group is not clearly defined in the given information. Constant variables could be the type of Daphnia used, the type of water (other than temperature), and the microscope used for counting heart - beats.

Step4: Form hypothesis and research question

A possible hypothesis could be: If the water temperature increases, then the heart rate of Daphnia will increase because they depend on external heat sources for their metabolism. A research question could be: How does water temperature affect the heart rate of Daphnia?

Answer:

As the temperature increases, the number of heart beats increases, suggesting they have an increased metabolic rate.
Data type: Quantitative.
Independent Variable: Water temperature.
Dependent Variable: Number of heart beats (heart rate).
Control Group: Not clearly defined.
Constant Variables: Type of Daphnia, type of water (other than temperature).
Hypothesis: If the water temperature increases, then the heart rate of Daphnia will increase because they depend on external heat sources for their metabolism.
Research Question: How does water temperature affect the heart rate of Daphnia?