Candle in a Box

"Candle in a Box"
PRETEST

SLiBS: Pre-test Assessment for "Candle in a box"

< Question 1 >
< Question 2 >
< Question 3 >
< Question 4 >

Question 1: Sunset

When the sun sets below the horizon on a cloudless day, the temperature of the of the environment drops. Below is a list of recorded temperatures (degrees F) and the times they were recorded.

(PM)	7:00	7:30	8:00	8:30	9:00
(^o F)	92	90	84	78	76

a) Please graph these data clearly by conventional methods.

b) From the data presented, estimate the time the sun went below the horizon.

c) A unique species of mosquito will bite humans only when the air temperature is 80.0 degrees F or below. A field researcher wants to stay outside as late as possible in order to continue collecting data, but also wants to avoid being bitten by this particular species of mosquito. Based on your graph for question 1a, give your best estimate, to the minute, of the time that person should go inside to avoid a mosquito bite.

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Question 2: Snake on a Road

It is a winter day and the air temperature is 40^o F. A snake in his burrow is at equilibrium with the burrow temperature of 40^o F. Near the burrow is a black asphalt road (Farm Road 1508), which is, and remains at, a steady 80^o F. The snake slithers out onto the road to get warm.

Assume the snake can absorb heat at a constant rate when its body temperature is between 40^o and 60^o F. Also assume it takes 10 minutes for the snake to reach a body core temperature of 60^o F. Construct two graphs. In the first graph plot body heat vs. time. In the second graph plot the rate of heat gain vs. time.

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Question 3: Human in a Box

Assume there is a cubic box that is 1 meter on each side. Also assume that in the exact center of this box there is a human being who for the purpose of this model is represented by a 37^o C point source of heat (= pinpoint source of heat ), which radiates heat. Temperature probes are being used to measure the air temperature inside the box. The temperature probes can record temperature to within one degree of accuracy. Assume the temperature is 27^o C everywhere in the box except where it is influenced by the heat point source.

The graph below displays the actual change in temperature as one moves away from the heat point source.

| GRAPH |

Express as a percentage the volume of the space which the temperature probe detects as different from the ambient (27^o C).

One of the following formulas below might be helpful:

A = P r ²
V = 4/3 P r ³
P = P d

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Question 4: Define the term interpolation.

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