Hypothesis and experimentation

Correct answer: A. A testable possible explanation

A hypothesis is a possible explanation that can be tested by experiment. In exams identify testability.

Correct answer: B. Amount of light

The amount of light is changed by the student so it is the independent variable. In exams find the factor deliberately changed.

Correct answer: C. Growth of the plant

Plant growth is measured as a result of changing light so it is the dependent variable. In exams identify the measured outcome.

Correct answer: D. To observe only the effect of the tested factor

Keeping controlled variables constant makes the effect of the independent variable clear. In exams focus on fair comparison.

Correct answer: A. If water temperature increases then sugar will dissolve faster

The first statement gives a testable relationship between two variables. In exams identify testable if-then statements.

Correct answer: B. Type of seed

Keeping the seed type the same allows a fair test of water amount. In exams keep other conditions constant.

Correct answer: C. The effect of random errors is reduced

Repetition reduces the influence of unusual results and gives a more dependable average. In exams link reliability with repetition.

Correct answer: D. Review the hypothesis and perform a new test

Revising or rejecting an unsupported hypothesis and testing again is part of science. In exams follow evidence rather than expected results.

Correct answer: B. Amount of stain removed

The amount of stain removed is the measured outcome so it is the dependent variable. In exams choose the variable measured as the effect.

Correct answer: C. It makes the steps organised and repeatable

A written procedure allows the experiment to be repeated using the same steps. In exams link reproducibility with procedure.

Correct answer: D. The plant height is twelve centimetres

Quantitative data is information expressed through numbers and, when appropriate, a unit. It tells how much, how long, how tall, how heavy or how many, so it can be measured and compared more precisely. Descriptions such as colour, smell or surface feel are generally qualitative observations because they use words rather than a numerical measurement.

Option D is correct: a plant height of twelve centimetres contains the numerical value 12 and the unit centimetres. The statements that the solution is blue, the smell is strong and the leaf is smooth describe qualities, not measured amounts. A colour or texture could sometimes be studied using instruments, but as written these choices are qualitative descriptions. Thus, the number-and-unit observation is the quantitative datum.

Correct answer: A. So the cause of the result can be identified

Changing one variable at a time allows the result to be linked to that variable. In exams look for cause and effect.

Correct answer: B. The rate of evaporation will increase as temperature rises

This statement gives a testable relationship between temperature and evaporation. In exams check that both variables are clear.

Correct answer: C. It gives a better estimate of the general trend

An average combines several readings to give a typical value and reduce random variation. In exams link averages with reliability.

Correct answer: D. When chemicals may splash

Safety goggles protect the eyes from chemical splashes. In exams match safety equipment with the risk.

Correct answer: A. When its variables can be changed and measured

A testable hypothesis contains variables that can be controlled and measured. In exams look for observable evidence.

Correct answer: B. Type of surface

The type of surface is deliberately changed so it is the independent variable. In exams choose the factor changed by the experimenter.

Correct answer: C. It is very different from the other results

A value very different from the other readings is called anomalous. In exams check it and repeat the measurement if needed.

Correct answer: D. Whether the data support the hypothesis

The conclusion states from the data whether the hypothesis was supported. In exams give an evidence-based answer.

Correct answer: A. To measure the time taken to dissolve

A stopwatch measures time so it records the dissolving time. In exams correctly match apparatus with the quantity measured.

Correct answer: B. Using a suitably calibrated instrument

A calibrated and suitable instrument gives measurements closer to the true value. In exams link accuracy with proper apparatus.

Correct answer: C. Number of germinated seeds against amount of water

A suitable graph shows the relationship between two quantitative variables. In exams place the independent and dependent variables on the axes.

Correct answer: D. Apply the proper correction or adjust the instrument

Correcting for zero error makes measurements more accurate. In exams check the zero reading before use.

Correct answer: A. An observation is directly seen or measured while an inference explains it

An observation is direct evidence whereas an inference interprets that evidence. In exams separate fact from explanation.

Correct answer: B. Initial amount of water

Keeping the initial amount of water the same allows a fair comparison of location. In exams keep all conditions except the tested factor constant.