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FAQ: Instruments and Protocols

Below are answers to some common questions about GLOBE instruments and protocols:

Instruments

Users will need instruments, supplies and other pieces of equipment to conduct the GLOBE protocols. Many of these can be purchased from suppliers, while some can be made by students or others locally. Scientists have developed specifications for instruments to ensure accurate data collection and instrument affordability. GLOBE has carefully selected instruments for each of the protocols that meet the program’s standards for accuracy and accessibility.

Explore GLOBE-approved tools and instruments.

Users will need instruments, supplies and other pieces of equipment to conduct the GLOBE protocols. Many of these can be purchased from suppliers, while some can be made by students or others locally. Scientists have developed specifications for instruments to ensure accurate data collection and instrument affordability. GLOBE has carefully selected instruments for each of the protocols that meet the program’s standards for accuracy and accessibility.

Explore GLOBE-approved tools and instruments.

The GLOBE Program does not endorse any particular supplier but does identify companies believed to offer instruments required for GLOBE. Contact any potential supplier for instruments before ordering to verify that they meet current GLOBE specifications.

Find an instrument supplier.

Note: Several suppliers provide the same GLOBE instruments, and prices may vary. Suppliers sell individual items as well as complete kits. 

Many instruments will meet GLOBE Specifications. One will need to look at the current GLOBE Specifications (pdf) document to verify. Some instruments output their data in a format that is not available for entry into the GLOBE Data Entry web forms. In this case, one will need to determine if a method of unit conversion is available. If so, the data format can be converted and the data can then be entered into the system. For example, the Vernier Turbidity Sensor outputs data in a format called NTU. The NTU data can actually be converted to cm (centimeters) using a conversion chart (pdf). There are many other conversion charts online for various data formats.

The GLOBE Program and Implementation Office are not able to loan specific scientific equipment, however, some U.S. partners may loan equipment to schools in their area. Contact your nearest partner for short-term loan requests. Country Coordinators may also loan equipment to schools. 

Teachers can also contact local organizations, companies, local libraries, other teachers, parents, and anyone else who may have equipment.

Thermometers and Probes

Before you begin entering your measurements, complete the Thermometer Calibration and Reset Data Sheet (pdf) to ensure the accuracy of the thermometer.

GLOBE requires five test readings. They can be taken all in one day (at least one hour apart) or over the course of several days.

In order to complete the calibration sheet, you will need a second thermometer.

The first time you press the Max/Min buttons, you will see the highest and lowest temperatures over the past 24 hours. Press the Max/Min button twice to get to the D1 reading. The D1 reading is the maximum over the past 24 hours, starting from the time the reset button was pressed, so be sure that you hit the reset button during solar noon. 

Follow GLOBE's Data Tutorials to learn how to access the GLOBE data entry tool.

In the site definition page, select the Atmosphere site type, then select the Digital Multi-Day Max/Min thermometer type. Click on the reset data link and enter the date of reset. Add a note in the comments that you reset the thermometer.

To find out the date of last time your thermometer was reset, in the Data Entry page, under the Atmosphere site, click on Multi-Day Soil and Air Temperature New Observation data entry form. Once you open the form, you will see the last thermometer reset data.

Digital probes for GLOBE protocols can measure:

  • Temperature (soil, air, and water)
  • pH
  • Barometric pressure
  • Relative humidity
  • Conductivity
  • Dissolved oxygen

Probes must meet the specs given in the instrument specifications section of the Teacher's Guide Toolkit (pdf).

Replace your thermometer with a digital model. Do not use a uTube or mercury thermometer for recording maximum and minimum air temperatures, as this type of thermometer is dangerous due to its mercury.

Other Instruments

The GLOBE pH meter calibrates internally. The instrument will not calibrate if you do not follow its instructions exactly. The following instructions are especially important:

  • The pH meter must sit in water (up to the sampling line) for at least one hour prior to calibration. Be sure there is no residue on the electrode, which could affect the reading.
  • The pH meter should be calibrated first to pH 7. After rinsing off the electrode each time, calibrate it to pH 4 and pH 10. This sequence of buffers is important—pH 7 first, then 4 and finally 10.
  • Immerse the electrode in solution (up to the fluid line indicated), hit the CAL button, and the screen will flash. Wait for the value to stabilize. This took 4 minutes on one of the instruments tested. Hit HOLD to hold the value.

When this instrument works, it provides better accuracy and precision than the pH pen. If, after several attempts, you are unable to calibrate the instrument, return it to the vendor and ask for a replacement.

In order to connect a Davis or Earth Networks weather station to GLOBE, you must either be a trained GLOBE Educator or a trained Citizen Scientist living in the U.S.  

For Davis Weather Stations
See Sharing your Davis Weather Station Data with GLOBE (pdf).

For Earth Networks Weather Stations
If your Earth Networks, weather station meets GLOBE specifications (pdf), and you have the appropriate logging ability, all you need to do is define a site and indicate the thermometer type as "AWS." 

Non-GLOBE Certified Teachers/Schools
In order to be a contributor to GLOBE and submit observations (an automated process with your weather station), you should contact the Community Support Team at help@nasaglobe.org to obtain the required permissions.

If precipitation does not fall in the form of rain, the rain amount should be reported as missing, unless your instrument is a heated tipping bucket. Most consumer brand automated weather stations do not have heated tipping buckets. The best solution for most stations is to disable the recording of precipitation when snow is expected more than rain. While your rain gauge is disabled, report precipitation measurements to GLOBE as missing.

For individual cases where snow fell when rain was expected, edit that day’s data and change the rain amounts to missing. In addition, clear the snow away from the funnel of the instrument so that melting snow does not lead to incorrect data.

Protocols

In order to find recommended age or grade ranges for each protocol, check the Teacher’s Guide Toolkit (pdf). Several measurements will say "ALL" because they can be used by all age ranges.

To see the requirements to qualify for the GLOBE Science Honor Roll, visit Honor Roll Specifications.

For atmosphere observations, users are able to take data measurements anywhere within 100 meters of the weather station location. For measurements from a distance further away than that, users will need to define a new site. Users should always take new GPS readings for each new site, as they may be slightly different.