(precision of the caliper rule: ±0.05 mm) and precision of the scale (±0.1 g) are possible source of errors. 13. Experiment 3: test of a straw as the nozzle A test track was made to make the distance measurements easier. The same amount of air was used in all the experiments, with an air pump. Table 1: Distance (measured in m) travelled with and without a straw as the nozzle. Without a With a straw 2.49 3.38 2.12 4.05 2.02 3.15 Average 2.21 3.53 Standard deviation 0.25 0.47 The paper straw directed the flow, so the car could travel a larger distance for the same amount of combustible. The precision of the measuring tape (±0.05 cm) is a possible source of errors. 14. Experiment 4: chassis test Two different chassis (wedge and rectangular prism shapes) are tested in the same test track of the last experiment, using the pump to apply the same amount of air. Table 2: Distance (measured in m) travelled for different chassis' shapes. Rectangular prism Wedge 2.39 0.41 1.89 0.35 2.01 0.39 Average 2.10 0.38 Standard deviation 0.26 0.03 Even though the wedge shape was more aerodynamic, the chassis in rectangular prism had less rolling friction in its wheels, so it showed to be better. The precision of the measuring tape (±0.05 cm) is a source of errors again. 15. Experiment 5: surface test The test track and the same amount of gas (using an air pump) are used again. Both surfaces are made basically of the same material, but the first has slots and the second do not. Table 3: Distance (measured in m) travelled over different surfaces. With slots on the floor Without slots 2.39 2.49 1.89 2.12 2.01 2.02 Average 2.10 2.21 Standard deviation 0.26 0.25
(precision of the caliper rule: ±0.05 mm) and precision of the scale (±0.1 g) are possible source of errors. 13. Experiment 3: test of a straw as the nozzle A test track was made to make the distance measurements easier. The same amount of air was used in all the experiments, with an air pump. Table 1: Distance (measured in m) travelled with and without a straw as the nozzle. Without a With a straw 2.49 3.38 2.12 4.05 2.02 3.15 Average 2.21 3.53 Standard deviation 0.25 0.47 The paper straw directed the flow, so the car could travel a larger distance for the same amount of combustible. The precision of the measuring tape (±0.05 cm) is a possible source of errors. 14. Experiment 4: chassis test Two different chassis (wedge and rectangular prism shapes) are tested in the same test track of the last experiment, using the pump to apply the same amount of air. Table 2: Distance (measured in m) travelled for different chassis' shapes. Rectangular prism Wedge 2.39 0.41 1.89 0.35 2.01 0.39 Average 2.10 0.38 Standard deviation 0.26 0.03 Even though the wedge shape was more aerodynamic, the chassis in rectangular prism had less rolling friction in its wheels, so it showed to be better. The precision of the measuring tape (±0.05 cm) is a source of errors again. 15. Experiment 5: surface test The test track and the same amount of gas (using an air pump) are used again. Both surfaces are made basically of the same material, but the first has slots and the second do not. Table 3: Distance (measured in m) travelled over different surfaces. With slots on the floor Without slots 2.39 2.49 1.89 2.12 2.01 2.02 Average 2.10 2.21 Standard deviation 0.26 0.25