A student explored how temperature affects the transport of water in celery stalks. The water included a blue dye.
In plant stems such as a celery stalk, water is carried through the xylem tissue inside the vascular bundles.
The student followed this procedure:
Step 1 Select two stalks of celery and trim them so that each is 10 cm long.
Step 2 Set up an ice-cold water-bath C and a warm water-bath W. Put a beaker of blue dye in each water-bath, as shown in Fig. 1.1.
Step 3 Measure the temperatures of the water in water-bath C and water-bath W.
Step 4 Allow the blue dye to reach the same temperature as the water-baths for three minutes.
Step 5 After three minutes, place one celery stalk into each beaker of blue dye, as shown in Fig. 1.2. Leave the celery stalks in the blue dye for ten minutes.
Step 6 After ten minutes, measure the final temperatures of the water in water-bath C and water-bath W.
Step 7 Take the celery stalk out of the blue dye in water-bath C and place it on a white tile.
Step 8 Slice a cross-section across the celery stalk 5 mm from the end that was in the blue dye, as shown in Fig. 1.3.
Step 9 Inspect the xylem tissue of the cut section of celery stalk to check whether the blue dye can still be seen. Fig. 1.4 shows where the xylem tissue is located in a cut section of a celery stalk.
Step 10 If the blue dye is still visible in the celery stalk, cut a further 5 mm wide section from the dyed end of the remaining celery stalk. Keep cutting 5 mm wide sections from the celery stalk until the blue dye can no longer be seen in the cut section.
Step 11 Count how many sections cut from the celery stalk contain the blue dye.
Step 12 Carry out steps 7 to 11 again with the celery stalk from water-bath W.
(a(i))[1]
Complete Table 1.1 by working out the temperature change for each water-bath.
(a(ii))[4]
Set out a table and enter the results shown in Fig. 1.5. Make sure you include the number of sections cut and the total distance travelled by the blue dye in each celery stalk.
(a(iii))[2]
Calculate the rate at which the blue dye moves in the celery stalk in beaker W. Include the unit.
(a(iv))[1]
State a conclusion for this investigation.
(a(v))[1]
Explain why it is better to repeat an investigation.
(b)[2]
Identify two variables that were kept constant in this investigation.
(c(i))[2]
Identify the possible error, and describe an improvement to the method to reduce the effect of this error.
(c(ii))[1]
Suggest an improvement to the method that would reduce this source of error.
(d)[2]
Work out the volume of a cylinder that is 100 mm long and has a diameter of 0.06 mm. Use this formula: $v = \pi r^2 h$. Use a value for $\pi$ of 3.14. Give your answer to two decimal places.
(e(i))[3]
Line AB shows the body length of the black aphid. Measure the length of line AB in Fig. 1.6. Use the formula and your measurement to calculate the actual body length of the black aphid. $\text{magnification} = \frac{\text{length of line AB in Fig. 1.6}}{\text{actual body length of the black aphid}}$. Give your answer to one significant figure.
(e(ii))[3]
State three ways in which the leaf miner fly shown in Fig. 1.7 differs from the black aphid shown in Fig. 1.6.
(f)[4]
Draw a large diagram of the celery leaf shown in Fig. 1.8.