Biology 5090/42 — October/November 2023

Cambridge O-Level · Alternative to Practical · worked solutions for every part, with the mark scheme

questions

marks

minutes

Topics Experimental Contexts · Planning Experiments and Investigations · Observations and Measurements · Analysis, Conclusions and Evaluation · Microscopy and Biological Drawing

Q114MPlanning Experiments and InvestigationsObservations and MeasurementsAnalysis, Conclusions and EvaluationExperimental ContextsFree sample

Some animals that live in cold climates need to reduce the loss of heat from their bodies.

A student investigated the effect of using an insulating material on heat loss from an animal. They used a test-tube to represent the animal and some wool, which is known to be a good insulator.

They marked a line on the test-tube $2\,\text{cm}$ below the top.

They placed the wool in a beaker and inserted the test-tube so that it was completely surrounded by wool as shown in Fig. 1.1.

A second marked test-tube was placed in a test-tube rack as shown in Fig. 1.1. This had no insulation.

Hot water was added up to the lines drawn on both test-tubes.

Fig. 1.1

Immediately, a timer was started and the temperature of the water in both test-tubes was measured.

(a)

Suggest why both test-tubes were filled with water only up to the marked line.

______

(b)

In a notebook, the student recorded the temperature of the water in each test-tube every two minutes for ten minutes as shown.

Time: 2 4 6 8 10
No insulation: 66.5 60.5 55.5 52 49
With insulation: 73 69.5 66 63 61.5

Fig. 1.2 shows the thermometer readings at 12 minutes.

Fig. 1.2

(i)

Enter all the data for the temperatures in Table 1.1.

Table 1.1

time / minutes	water temperature / $^\circ\text{C}$ test-tube with insulation	water temperature / $^\circ\text{C}$ test-tube with no insulation
0	76.5	75.0
2
4
6
8
10
12

(ii)

Use the results in Table 1.1 to describe the loss of heat from the test-tubes and the effect of the insulation.

(c)

Humpback whales are large aquatic mammals that maintain a constant body temperature of $38\,^\circ\text{C}$ . They spend part of the year in cold polar water and part of the year in warm equatorial water.

Design an investigation that you could carry out to discover the effect of different surrounding water temperatures on the loss of heat by the humpback whale. Use a test-tube filled with water to represent the humpback whale.

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2 more questions

Q2Experimental Contexts · Observations and Measurements · Analysis, Conclusions and Evaluation · Planning Experiments and Investigations14M
Q3Experimental Contexts · Microscopy and Biological Drawing12M

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