Scientific questions and observations

Correct answer: B. Plant height

The measured result is the outcome that is recorded during an investigation. Here, the student measures the height of the plant each day, so plant height is the dependent variable. It may change in response to another factor, such as the amount of water, light, or type of soil. The factor deliberately changed by the investigator would be the independent variable, while other relevant conditions should be controlled.

Option B is correct because it names exactly what is measured. The amount of water may be an independent variable in a related investigation, but it is not the measured result described here. Soil type and pot colour are conditions or characteristics, not the stated outcome. Identifying the measured outcome helps distinguish the dependent variable from the factors being tested or controlled.

Correct answer: C. The water temperature is (25^\circ C)

Temperature is measured with a thermometer so this is an instrument-based observation. In exams look for a number and unit.

Correct answer: D. Record and investigate it

The direct answer is D: record the unexpected result and investigate it. Science does not allow a result to be removed merely because it disagrees with an expectation. Step by step: write the result exactly as observed; check the procedure, measurements, units, equipment, and possible recording errors; repeat the investigation when appropriate; compare the new evidence and report both expected and unexpected findings. Option D is correct because an unexpected result may reveal a new effect, a hidden variable, or an experimental error. Option A is wrong because deleting evidence creates a biased record. Option B is wrong because changing the result is dishonest and destroys its meaning. Option C is wrong because hiding it prevents others from checking the conclusion. A helpful cue is: surprising evidence is a reason to check, not a reason to erase.

Correct answer: A. Accuracy

Accuracy helps an observation represent what was actually seen or measured. Bias, rumours, and unsupported guesses can distort evidence and reduce its reliability.

Correct answer: B. How does heating for different durations change water temperature?

The direct answer is B: asking how heating for different durations changes water temperature. A scientific time-effect question changes the duration or time and observes a measurable result. Here, keep the water and heating conditions as constant as possible, heat it for different lengths of time, and record the temperature each time. Option A asks which fruit is sweet; it compares taste, not time. Option B is correct because heating duration is the changed factor and water temperature is the observed factor. Option C asks about beauty, which is subjective and unrelated to time. Option D asks who likes water, which concerns preference, not an experiment. The important reasoning is: different time periods are deliberately compared, so the effect of time can be investigated. Exam cue: find the question containing a time interval that is changed and an outcome that is measured.

Correct answer: C. With the eye level with the mark

Keeping the eye level with the scale reduces reading error. In exams remember the correct viewing angle.

Correct answer: D. Evidence

The answer to a scientific question should be supported by evidence obtained through observations, experiments, and investigation. Imagination may suggest an idea, but it becomes a scientific answer only when evidence supports it. Exam tip: words such as “evidence”, “observation”, and “experiment” usually indicate a scientific conclusion.

Correct answer: A. The result becomes more reliable

Taking several measurements reduces the effect of error and improves reliability. In exams remember the importance of repetition.

Correct answer: B. Touch

Touch can be used to feel whether a leaf is smooth or rough. In exams match the sense with the property.

Correct answer: C. Hearing

The direct answer is C, hearing. Sound is a vibration that reaches the ear, and the sense of hearing allows the brain to recognise it. To observe sound in ordinary life, we listen and notice its loudness, pitch, or duration. Option A, sight, helps us observe light, shape, and colour; it cannot directly hear sound, although we may sometimes see an object vibrating. Option B, touch, can sometimes detect vibrations, but it is not the normal or primary sense for observing sound. Option C is correct because ears receive sound waves. Option D, taste, detects substances in food and does not detect sound. Exam cue: sound is heard, light is seen, and an odour is smelt.

Correct answer: D. Smell

Smell is detected by olfactory receptors in the nose, so the olfactory sense is correct. Sight detects light and colour, not odour. Exam tip: Link words such as smell, fragrance and odour with the olfactory sense.

Correct answer: A. The solution is blue

The word “blue” states the colour of the solution, so option A is an observation related to colour. Option B describes volume, option C describes length, and option D describes temperature, not colour. Exam tip: words such as colour, smell, and state usually indicate qualitative observations.

Correct answer: B. It records the day on which the observation was made

Writing the date creates a clear record of the day on which an observation was made. It helps compare results from different days and understand the sequence of changes. Recording only the time is not enough because the date identifies the day. Exam tip: enter the date, time, and measurement separately in an observation table.

Correct answer: C. Do different amounts of water affect plant growth?

In this question the amount of water is changed and plant growth can be measured. In exams identify the independent variable.

Correct answer: D. After studying observations and data

A conclusion is drawn from the evidence and data obtained. In exams connect conclusions with evidence.

Correct answer: A. The stone has a mass of 50 grams

Option A gives a numerical value, 50, along with the unit gram for mass, so it is a statement written with a measurement. “Very heavy” may describe an observation or comparison, but it does not provide a definite number and unit. Exam tip: A measured statement usually includes a number and a unit, such as gram, metre, or second.

Correct answer: B. Soil and pot size

Keeping soil and pot size the same makes the comparison fair. In exams identify controlled factors.

Correct answer: C. Which flower is the best?

An opinion-based question asks for a personal preference or judgement rather than a result that can be measured by a clear, shared procedure. The word “best” does not have one fixed scientific meaning unless criteria are first defined, such as fragrance, colour, size, or ability to attract insects. Different people may choose different flowers and still express reasonable personal opinions. The question therefore cannot be answered objectively as written.

The other choices ask for measurable information: water’s boiling temperature can be measured under stated conditions, plant growth can be recorded in days, and leaf length can be measured with an instrument. Their answers can be checked by repeating the observation or measurement. Thus, option C is correct because choosing the best flower depends on preference. It could become investigable only after defining a specific criterion and a method for measuring it.

Correct answer: D. Take the correct measurement and correct it

Scientific observations must be honest and traceable. If a value has been written incorrectly, the record should not be hidden, erased without explanation, or replaced by a guess. The correct response is to check the instrument and procedure, repeat the measurement carefully, and record the corrected value according to the activity's recording rules. If required, the original error should remain visible with a clear correction.

Therefore option D is correct because it relies on new evidence rather than imagination. Deleting the whole table loses useful observations, and guessing creates an unsupported result. A corrected measurement should be made under the same conditions as far as possible. This practice improves accuracy and allows another person to understand how the final observation was obtained.

Correct answer: A. When the cause of a change is to be known

Curiosity about the cause of a change can lead to a scientific question. In exams identify cause and effect.

Correct answer: B. To make the meaning of the measurement clear

A measurement is not just a number; it describes the amount of a physical quantity. The unit tells us what standard the number is compared with and what kind of quantity is being reported. For example, a length of 5 without a unit is incomplete, because it could mean 5 metres, centimetres or another unit. Writing the unit makes a result understandable, comparable and useful to another person.

Option B is correct because a unit clarifies the meaning of a measurement. Options A and C treat the unit as decoration or unnecessary extra writing, while option D wrongly suggests that units make an experiment difficult. In science, the number and unit should be recorded together, such as a mass in grams, a time in seconds or a temperature in degrees Celsius. The appropriate unit should match the quantity being measured.

Correct answer: C. The sugar dissolved in two minutes

Option C includes “two minutes,” which is a measurement of time; therefore, it records the time taken for the sugar to dissolve. The other options describe properties such as colour, texture, and clarity, not time. Exam tip: Look for units such as seconds, minutes, or hours to identify an observation involving time.

Correct answer: D. Objective

An objective person records the result correctly without changing it. In exams consider objectivity a scientific quality.

Correct answer: A. Does sugar dissolve faster in hot water?

The relationship between hot water and dissolving speed can be tested experimentally. In exams identify a question with two variables.

Correct answer: B. It is clear and evidence-based

A good scientific observation is clear and based on evidence. In exams choose the factual option.