20th February 2020 8:02 am

How to plan a field trip to collect water and soil samples

How to plan a field trip to collect water and soil samples

Decide where you want to go and how to get there

• Is it safe?
• Will you be able to get there and back in the time? Does it need to be in daylight?
• Is it the right time of year to find what you are looking for?
• Always let someone know where you are going.
• Be aware of the risks of falling or slipping, especially near water.  Always wear appropriate footwear.
• If it is a beach, will the tide be right for your collecting?
• Wear appropriate clothes to keep warm and shoes/boots which won’t slip and can keep you dry.

Take with you

• Notebook
• Pencil/waterproof marker pen
• Collecting jars/ scoop or tools to measure sand/soil/water
• A phone if you have one
• A field microscope and petrie dishes/tweezers/pipettes if appropriate.

Collecting samples 

It is important that you are able to remember where the sample came from. Many samples taken one the same day can easily get mixed up. Get into a routine and be disciplined about labelling the samples.

Unique code

Label the sample container with a unique code. For example: SB1, SB2. ( For Southerndown Beach). Make sure this does not rub off if wet. 

In a notebook, for each unique code marked on the sample, note the following

• Date 
• Location  – for example,  – beach, northern side, high water mark, surface sand. 
• If  you have access to a smart phone, note the GPS location coordinates. If not, carefully note where the sample came from. 
• Take a picture if possible to help identify the location.

Keep the samples safe and analyse  with the field microscope or back at school or home. 

The GPS ( Global Positioning System) coordinates

These enable every location on the planet to be marked with a unique code. They accurately mark the position of the sample.

Under the longitude and latitude system, the Earth is divided into a grid of horizontal and vertical lines. The horizontal lines are called latitude lines; because they run parallel to the equator, the vertical lines are called longitude lines and they run north south through the North and South poles.

The first number in the GPS coordinate is the latitude, where it is north or south of the equator. North is a positive number, south a negative number. So Chankhasi School is at 13 degrees south and Ysgol Plasmawr is 34 degrees north of the Equator.

The north pole is +90 degrees, the South Pole is -90 degrees. 

The second number is the longitude. This tells us where the place is, left or right going around the world starting at a place called Greenwich in London ( the Greenwich meridian). Going east, the number is marked as negative, going west the number is marked as positive.

Chankhasi School is 34 degrees west of the Greenwich Meridian. It is marked positive  because it is west.

Ysgol Plasmawr is 3 degrees east of the Greenwich meridian. It is marked negative because it is east.

There are (at least) two ways to find out the GPS coordinates using a smart phone.

1. Go into compass. The coordinates will appear at the bottom of the screen as degrees, minutes and seconds. 

2. In google maps touch the location until a red marker appears. Dropped pin will appear at the bottom of the screen. Touch this and the GPS coordinates will appear as a decimal.

For example

Chankhasi School,Malawi

  -13.0538069,                           34.3242586

 13° 3 min 13.7 sec South.      34° 19 min 27.3 sec East

Ysgol Plasmawr, Wales

51.4972821,                              -3.2465203

51° 29 min 50 sec North,        3° 14 min  47 sec West

Each degree works out at about 69 miles. The more numbers after the decimal point in the GPS coordinate, the more accurate the position. The google maps claim that the coordinates allow the spot to be marked to within 4 meters of accuracy. 

Stephanie Matthews Nov 2019