Buried Treasure

Source:

The Moine Mhor National Nature Reserve, local schools pack (SNH)

Time

15 minutes at school and 15 minutes at a peat bog

You will need

• 2p and 10p coins wrapped in three identical thin cloth bags
• some bright coloured wool
• a trowel

Did you know?

It is the acidity of a peat bog that makes the peat. The bog plants cannot rot away when they die because the bacteria that enable the decaying process can't live in the acid conditions. As a result, when the vegetation dies it builds up in layers, with new growth on the top and old growth underneath. Over thousands of years peat is formed from the squashed remains. The ground can actually become higher than the surrounding non-bog land; it becomes a raised bog growing in height at about 1 mm a year. The bog doesn't dry out because the peat and the living mosses, particularly sphagnum mosses, absorb and retain huge quantities of water. The bog soaks up water like a giant sponge. Bog plants are very specialised because they live in very acidic, very water logged conditions. 

Before the activity

Explain the experiment to the class and show them the coins and the identical bags. One of the bags will be kept in the class as a ‘control’ item (the original state of the coins). One bag will be buried in the school grounds. One bag will be buried in the peat bog. Encourage the class to think about how to make this experiment a fair comparison. (The coins should be equally divided between the bags, the bags need to be the same, they need to be buried for the same length of time). Get one of the bags of coins buried in the bog you will be visiting at an easily accessible marked spot, a few days before the class visit.

The activity

Let the class examine the remaining coins and see how dirty they are, not shiny at all. Divide the remaining coins into the remaining two bags and keep one in the classroom and go outside with the class to bury the other one in the school grounds. Mark the spot with a stick and coloured wool. After a few days dig up the treasure, wash off the soil and let the class compare them to the coins that were not buried. If the buried coins are a little shinier then your soil is slightly acidic.

Take the class to visit the chosen peat bog. Either take them straight to the coins or have a treasure hunt game first, with clues that take them to the location of the buried treasure.  You could also do one of the other activities in the 'Peatlands' sections.  

Wash the coins and compare them to the other two sets of coins. Which are the shiniest and why?

You could also test the acidity of the peat bog and the school ground soil using pH paper or a pH meter.

Suggested Follow up

Take a tiny sample of peat from the bog, just enough and no more, for the use of the class. Then do the Soil Sampling activity from the School Grounds section.

Find out why sphagnum moss is able to hold so much water. Look at the moss through hand lenses.

Find out more about peat and its uses, and why peatlands are important in the fight against global warming.

Downloads

SNH Publications: Education and Teachers Resources:

• Schools Out Peatlands pack
• Wild Wet and Wonderful
• All About.... Sphagnum Moss

Curriculum Links

Science

AgeRange

2, 3