Lab Investigation 1 - Why Do Liquids Evaporate at Different Rates?

Guiding Question

Why do liquids evaporate at different rates?


Have you ever had a sunburn or high fever? If so, you may have used rubbing alcohol to help cool your skin. The alcohol works because it evaporates quickly and lowers skin temperature. The evaporation of a volatile liquid is an endothermic process that results in a temperature decrease. The magnitude of temperature decrease is related to the strength of intermolecular forces of attraction. Rate of evaporation can be described as the change in temperature divided by the time it takes to reach the lowest temperature
ΔT/Δt (°C/s).
In this experiment, you will investigate factors that determine the strength of intermolecular forces by determining the rate of evaporation for a series of volatile liquids.


As you complete this investigation you will:

Materials Available for Use

  • Distilled water, H2O
  • Acetone, C3H6O
  • Methanol, CH4O
  • Pentane, C5H12
  • Propanol, C3H8O
  • Ethanol, C2H6O
  • Butanol, C4H10O
  • Rubber bands
  • Chromatography paper
  • Molecular model kit
  • Vernier LabPro system with temperature probe

Safety Precautions

Wear goggles at all times.

Getting Started

Use the Molecular Model kit to make models of each of the compounds that will be studied in Investigation 1 and consider the following questions as well as those in the PreLab activity.

PDF file


Set up the data collection program to collect data for 300 seconds.
Wrap the probe with chromatography paper and secure with a rubber band. Wrapped probes provide more uniform liquid amounts, and generally greater
values than bare probes.
Stand the probe in the liquid until the temperature reading is stable, hit start and collect data for 15 seconds to establish the initial temperature, Ti. Then remove the probe from the liquid.
Use the statistics function to find the minimum and the maximum temperature readings.
NOTE: The minimum temperature reading may occur before 300 seconds for some liquids.


Once you have completed your research, you will need to prepare an investigation report that consists of three sections. This report may require more than 2 pages with data tables. This report must be typed and any diagrams, figures, or tables should be embedded into the document.
Remember:  An argument is not just an answer to the question. It is a claim or conclusion supported by evidence with a rationale for why the evidence supports the claim or conclusion.