Measuring With pH Paper

Measuring Liquids with a Garden Soil pH Test Kit

To measure pH, pour 1/4 teaspoon of the mixture you want to test into the test container, and add 1/4 teaspoon of the test solution provided in the kit. Cover the container and shake once or twice to mix, or stir if necessary. Compare with the color chart provided with the kit and write down the result.

Tips

• Except for wide-range pH test paper, all the materials called for in these experiments, including distilled water and borax, can be obtained at grocery stores or from local lawn and garden stores or nurseries.
• Wide-range pH test paper is inexpensive, but not easily obtained. A school science laboratory will probably have it or can order it, or you may order it through a biological supply company. Litmus pH paper is usually included in chemical sets sold at toy stores for children over 8 years old.
• For the names of supply companies, you can consult the yellow pages of your telephone directory under a heading such as "Laboratory Equipment and Supplies." If your local directory does not have such a heading, ask your teacher for suggestions or try the yellow pages from a larger city. Telephone directories are available at many libraries.
• Inexpensive garden soil pH testing kits are available at most lawn and garden stores or nurseries. These testing kits usually contain a pH indicator solution that covers a range of at least pH 4 to 10, which is wide enough for most of the following experiments.
• You may substitute baking soda for household ammonia in the experiments. If you do, be sure to stir well because baking soda does not dissolve easily in water unless heated. The pH of undissolved baking soda will not be the same as dissolved baking soda.
• You may substitute fresh-squeezed lemon juice for white vinegar. Lemon juice is slightly more acidic than the vinegar sold in grocery stores. White vinegar is preferred over cider vinegar or lemon juice because it is colorless and relatively free of impurities.
• Use clean, dry containers and utensils.

Safety in the Laboratory

• Eye protection (goggles or safety glasses) must be worn when working on experiments. Make a habit of putting them on before the experiment begins and keeping them on until all clean-up is finished.
• Do not eat, drink, or smoke while in the laboratory.
• Do not taste any chemical.
• Long-sleeved shirts and leather-topped shoes must be worn at all times.
• Long hair must be tied back, so it will not fall into chemicals or flames.
• Do not work alone; work with an adult.
• Never perform any unauthorized experiment.
• All glassware must be washed and cleaned. Wipe all counter surfaces and hands with soap and water.
• All experiments that produce or use chemicals that release poisonous, harmful, or objectionable fumes or vapors must be done in a well-ventilated area.
• Never point the open end of a test tube at yourself or another person.
• If you want to smell a substance, do not hold it directly to your nose. Instead, hold the container a few centimeters away and use your hand to fan vapors toward you.
• When diluting acids, always add the acid to the water; never water to acid. Add the acid slowly.
• Flush with large quantities of water when disposing of liquid chemicals or solutions in the sink.
• If you spill any acid or base material on you, wash the exposed area with large amounts of cold water. If skin becomes irritated, see a physician.

Recording Observations

• Use a bound notebook so that pages are not lost.
• Write complete sentences for all written entries.
• Use drawings as needed.
• Date each entry (even drawings).
• Use the title of the experiment as your first entry.
• When your observation entries have been completed, write your answers to the questions that follow each experiment.
• Write your own thoughts about the experiment as the conclusion