A student investigated the heat loss of livestock in windy vs sheltered conditions using beakers of hot water to represent the animals. One beaker was placed in front of an electric fan (representing unsheltered, windy conditions) and another was placed in a calm area away from the fan (representing sheltered conditions). Both beakers were filled with the same volume of hot water and their temperatures were recorded at intervals of 15 minutes over 30 minutes. This was repeated for four trials. The results are shown below:
| Trial | Unsheltered - 0 min | Unsheltered - 15 min | Unsheltered - 30 min | Sheltered - 0 min | Sheltered - 15 min | Sheltered - 30 min |
|---|---|---|---|---|---|---|
| 1 | 75 | 52 | 38 | 75 | 61 | 50 |
| 2 | 72 | 49 | 36 | 72 | 58 | 48 |
| 3 | 70 | 48 | 35 | 70 | 57 | 47 |
| 4 | 74 | 51 | 37 | 74 | 60 | 49 |
How many times did the student measure the temperature of the water in the beakers under unsheltered (fan) conditions during the investigation?
The diagram below shows one of the temperature readings during the investigation.
Use the diagram and the information in the table to complete the following sentence:
"The reading on this thermometer is 58∘C58^\circ\text{C}58∘C, which suggests the reading was taken from a beaker after 151515 minutes kept under sheltered conditions."
What was the independent variable (the variable that the student chose to change) in this investigation?
What was the dependent variable (the variable measured by the student) in this investigation?
Explain why the student kept other variables constant.
Give one way that the student could make his temperature measurements more accurate.
The results of this investigation suggest that meat production would be less efficient if farmers kept their animals in unsheltered, windy areas rather than sheltered areas. Use the data and your biological knowledge to explain why.
