A student investigates the evaporation of water from an open container.

Plan an experiment which will enable the student to investigate how the initial temperature of the water affects the rate of evaporation (defined as the mass of water evaporated in a fixed time).

The mass $m_e$ of water evaporated can be determined by using the equation:

$$m_e=m_b-m_a$$

where $m_b$ is the mass of the container and water before the evaporation period, and $m_a$ is the mass of the container and water after.

The apparatus available includes:

• a beaker (open container)
• a supply of hot water and cold water
• a thermometer
• a stop-watch

You do not need to write about any safety precautions.

In your plan:

• list any additional apparatus needed
• explain briefly how to do the experiment, including what measurements need to be taken
• state the key variables to keep constant
• draw a table, or tables, with column headings, to show how to display the readings (you are not required to enter any readings in the table)
• explain how to use the readings to reach a conclusion.