A student is studying how water evaporates from an open dish. Design an experiment that would allow the student to compare how evaporation changes when dishes of different diameters are used. The mass $m_e$ of water evaporated can be found from the equation: $m_e=m_b-m_a$ where $m_b$ = the mass of water in the dish before experiment and $m_a$ = the mass of water in the dish after experiment. The apparatus available includes: a range of shallow dishes with different diameters; an adjustable laboratory lamp to heat the water; a variable power supply for the lamp; a stop-watch; a supply of cold water. You do not need to write about any safety precautions. In your plan: list any extra apparatus required; give a short explanation of how the experiment should be carried out, including the measurements that must be made; state the main variables that should be kept the same; draw a table, or tables, with column headings, to show how the measurements would be recorded (you do not need to include any measurements in the table); explain how the measurements would be used to decide on a conclusion. You may include a diagram or add to Fig. 4.1 if this helps to make your plan clearer.
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Design an experiment that would allow the student to compare how evaporation changes when dishes of different diameters are used. The mass $m_e$ of water evaporated can be found from $m_e=m_b-m_a$. Your answer should include any extra apparatus, the procedure, the measurements to be made, the control variables, suitable headings for a results table, and how the measurements would be used to reach a conclusion.
Worked solution & mark scheme
This 7-mark question has a full step-by-step worked solution and mark scheme. One marking point: “MP1 apparatus: a ruler and a balance / measuring cylinder” …