Unit 38 — Experimental Reports

Step 1 · Read the report

Read the report once to understand the experiment. Then look carefully at the method and results.

Does warmer water help sugar dissolve more quickly?

Aim
To investigate whether the temperature of water affects the time taken for sugar to dissolve.

Method
Three clean beakers were used. One hundred millilitres of water was poured into each beaker. The water in the first beaker was kept at about 20°C, the water in the second was heated to about 40°C, and the water in the third was heated to about 60°C. One level teaspoon of sugar was added to each beaker. Each mixture was stirred at the same steady rate. The time taken for the sugar to disappear from view was measured with a stopwatch. The experiment was repeated, and the average time was calculated for each temperature.

Results

Water temperature	Trial 1	Trial 2	Average time
20°C	92 s	88 s	90 s
40°C	55 s	51 s	53 s
60°C	31 s	29 s	30 s

Conclusion
In this experiment, the sugar dissolved in the shortest time in the warmest water. The results suggest that, under these conditions, increasing the water temperature reduced the time taken for the sugar to dissolve. Further trials could help to confirm the pattern.

Remember: an experimental report usually explains the aim, method, results and conclusion. The method often uses the passive because the actions and materials matter more than the person doing them.

Step 2 · Check your understanding

Choose the best answer for each question, then check your work.

1. What was the experiment designed to investigate?

Whether different amounts of sugar change the colour of water. Whether water temperature affects how quickly sugar dissolves. Whether stirring makes water warmer.

2. What was kept the same in each beaker?

The water temperature. The amount of water and sugar, and the stirring rate. The time taken for the sugar to dissolve.

3. What was the average dissolving time at 40°C?

30 seconds. 53 seconds. 90 seconds.

4. Which statement is best supported by the results?

In these trials, sugar dissolved more quickly at higher water temperatures. Every solid dissolves instantly in hot water. Temperature is the only factor that can affect dissolving.

Step 3 · Notice the language

Compare the active and passive sentences. Both can describe the same action, but they put the focus in different places.

Active voice: focus on the doer	Passive voice: focus on the action or thing affected
The student poured the water into each beaker.	The water was poured into each beaker.
The student heated the water to 60°C.	The water was heated to 60°C.
The student added sugar to each beaker.	Sugar was added to each beaker.
The student recorded the time.	The time was recorded.

How is the passive formed?

Present simple: am / is / are + past participle
The temperature is measured carefully.

Past simple: was / were + past participle
The temperature was measured carefully.

To change an active sentence into a passive sentence:

Move the object of the active sentence to the beginning.
Use the correct form of be for the original tense.
Add the past participle of the main verb.
Include by + agent only when the person doing the action is important.

For example: “The student measured the temperature” → “The temperature was measured (by the student).” The past simple stays past simple; the tense does not change.

Step 4 · Change active sentences into the passive

Rewrite each sentence without changing its meaning or tense. Use the words in brackets as the beginning of your answer. You do not need to include “by the student”.

1. The student poured 100 ml of water into each beaker. (100 ml of water)

2. The student heated the water in one beaker to 60°C. (The water)

3. The student added one teaspoon of sugar to each beaker. (One teaspoon of sugar)

4. The student stirred each mixture for ten seconds. (Each mixture)

5. The student recorded the time taken for the sugar to dissolve. (The time)

Show model answers

100 ml of water was poured into each beaker.
The water in one beaker was heated to 60°C.
One teaspoon of sugar was added to each beaker.
Each mixture was stirred for ten seconds.
The time taken for the sugar to dissolve was recorded.

Equivalent correct wording is acceptable. Capital letters and final punctuation are not essential for this exercise.

Step 5 · Complete the procedure

Complete the report with the past simple passive form of the verbs in brackets.

Three clean beakers

. One hundred millilitres of water

into each beaker. The water in the second beaker

to about 40°C. One level teaspoon of sugar

to each beaker. Each mixture

at the same steady rate. Finally, the time taken for the sugar to dissolve

.

Show model answers

were used · was poured · was heated · was added · was stirred · was recorded

Language point: the subject determines whether we use was or were. “Three clean beakers” is plural, so we write “were used”. The other subjects are singular.

Step 6 · Interpret the results

A good report separates what was observed from what the evidence suggests.

1. Which sentence reports an observation from the results table?

The average time at 60°C was 30 seconds. Hot water always makes every substance dissolve faster. Temperature is the only thing that matters.

2. Which conclusion is appropriately cautious?

These results prove that all substances dissolve faster in hot water. In these trials, the sugar dissolved more quickly as the water temperature increased. The experiment was useless because the times were different.

3. Why should the experiment be repeated?

To make the report longer. To check whether the pattern is consistent and reduce the effect of chance variation. To guarantee that the conclusion applies to every substance.

Write one cautious conclusion

In this experiment, the sugar dissolved as the water temperature increased.

Step 7 · Reconstruct the report

Turn the notes into a short report. Use the passive where it helps keep the focus on the procedure.

Notes

Aim: test whether water temperature affects the time taken for sugar to dissolve.
Method: three beakers; 100 ml water in each; temperatures 20°C, 40°C and 60°C.
One teaspoon sugar added to each; mixtures stirred at the same rate.
Average times: 90 seconds at 20°C; 53 seconds at 40°C; 30 seconds at 60°C.
Conclusion: in these trials, sugar dissolved faster at higher temperatures.

Reconstruct the report one sentence at a time.

Use the notes to write each part. After each sentence, press Return or move to the next field to receive feedback. Your wording does not have to match the model exactly.

1. Aim: State what the experiment investigated.

2. Method: Describe the beakers and amount of water.

3. Method: State the three water temperatures.

4. Method: Describe adding sugar and stirring.

5. Results: Report the average time at 20°C.

6. Results: Report the average time at 40°C.

7. Results: Report the average time at 60°C.

8. Conclusion: State what the results suggest, without overgeneralising.

Step 8 · Write a new experimental report

Use the results below to write a report of your own. This experiment investigates how the length of stirring affects the time taken for sugar to dissolve.

Experiment notes

Three beakers each contained 100 ml of water at 40°C.
One teaspoon of sugar was added to each beaker.
Mixture A was stirred for 5 seconds; mixture B for 15 seconds; mixture C for 30 seconds.
The same stirring speed was used.
Observed dissolving times: A = 70 seconds; B = 52 seconds; C = 40 seconds.

Mixture	Stirring time	Time until sugar disappeared from view
A	5 seconds	70 seconds
B	15 seconds	52 seconds
C	30 seconds	40 seconds

Write your report (about 120–160 words).

Self-check

I have stated the aim. I have described the method in a clear order. I have used the passive where it is useful. I have included the results accurately. My conclusion is limited to what these results show.

Final reminder: an experimental report is not just a list of steps. It tells the reader what was investigated, how it was tested, what was observed and what can reasonably be concluded.