CIESE - International Boiling Point Project

Project Finished - Next Run Spring 2009

Experiment Help

Need Help Converting to mL?

If you measure the volume of water in cup units, you can convert to mL using one of the unit conversion calculators in the Reference Material section. (Remember that 1 cup = 8 fluid ounces). You can also convert other units of volume into mL using one of the conversion calculators. Or, if you would prefer to do it by hand, 1 fluid ounce = 29.6 mL.

Need Help Finding Your Town's Elevation?

You might try contacting your town hall to ask the town engineer or looking on a topographic map of the area. If you have access to a GPS unit, you can get the exact elevation of your classroom. The elevations for some locations (including online topographic maps) can be found using links on the Reference Material page. However, most of the locations are for U.S. cities and towns.

Need Help Converting Feet to Meters?

For this project, elevation needs to be reported in meters. On most U.S. maps and databases, elevation is given in feet so you will need to convert the elevation into meters. Try using one of the unit conversion calculators listed in the Reference Material section. Or, if you would prefer to do it by hand, 1 foot = 0.3048 meters.

Need Help Calibrating a Thermometer?

You should use the best possible thermometer(s) you can obtain and preferably one with at least one degree intervals. It is important that the thermometer be calibrated because if it is off by even a degree or two, it could affect the results of the experiment. One way to calibrate your thermometer is to prepare a mixture that is one part liquid water and one part crushed ice. Let the ice-water mixture sit for 10-15 minutes to reach the lowest temperature possible. Then place the bulb of your thermometer in the mixture and move it around so that it is thoroughly cooled. The thermometer should read between 0.0 degrees Celsius and 0.5 degrees Celsius. (The freezing point of water is 0 degrees Celsius). If it does not, try another thermometer.

If you can't find an acceptable thermometer, record the amount that the temperature is off by and adjust your boiling point reading by this amount. For example, if your thermometer reads 2.5 degrees Celsius instead of 0.0 degrees Celsius in the ice mixture, it is 2.5 degrees higher than it should be and you should subtract 2.5 degrees from your observed boiling point reading. If, on the other hand, your thermometer reads -3.0 degrees Celsius in the ice mixture, it is 3.0 degrees lower than it should be and you should add 3.0 degrees to your observed boiling point reading. This is not an exact solution but it will serve our purposes. If you find that one of your thermometers is way off, you might consider not using it at all in the experiment.

If you have numerous students/groups doing this experiment with a number of different thermometers, the averaging of their results will help to offset any error that a particular thermometer might have.

Need Help Converting Degrees Fahrenheit to Degrees Celsius?

If you don't have access to a Celsius thermometer you can still use a Fahrenheit thermometer in the experiment but all temperature readings have to be reported in degrees Celsius. You can use one of the unit conversion calculators listed in the Reference Material section to convert from Fahrenheit to Celsius. Or, if you would prefer to do it by hand, the formula is: C = (F - 32) X 0.555.

Need Help Setting Up the Equipment?

It is important that the bulb of the thermometer does not rest directly on the bottom of the pot because depending on the material that the pot is made of, the temperature of the pot could be higher or lower than the temperature of the water. There are some thermometers that are suspended in a metal tube with the bulb actually a few centimeters from the bottom of the tube. These are acceptable to use because the bulb doesn't actually rest on the bottom of the pot. However, if you do not have access to one of these thermometers, you can clamp the thermometer in place with a special thermometer clamp or a buret clamp. If you use a buret clamp (as shown in the first photo below on the right), make sure you pad it with something to secure the thermometer. In the photo the thermometer is placed in a rubber stopper which then fits into the buret clamp. If you don't have the necessary equipment for this kind of set-up, you can secure the thermometer using a string or rubber band to a piece of wood that can then be placed in the water.

Here are some additional photos showing how to set up the thermometer. A hot plate is used to heat the water in the beaker.