The week before last, we had the wonderful opportunity of hosting a geophysics open day with Big Heritage as part of their #digBlacon community archaeology project.
Big Heritage’s Blacon project encourages community engagement and active lifestyles through archaeological investigations over one of the oldest parts of Blacon. Our survey area was a communal green adjacent to the site of the now buried Blacon Hall. There was a great turnout with a nice balance of adult volunteers and eager children. We believe it is never too early or too late to become engaged with heritage and science; so we were excited to develop activities for both children and adult participants.
Chrys managed the hands-on children’s activity for understanding earth resistance.
“We wanted to simplify the concept of current flowing through the earth with an activity that was both visual and hands-on. We explored electric current by first making simple circuits with light bulbs and batteries. The higher-level concept of how electric current moves through the earth was understood by making circuits using conducting clay (recipe from Squishy Circuits). We used a multi-meter to measure the potential difference, watching how it differed between the different shapes of clay. The kids had a blast playing with the clay! It was great because they could shape the clay into whatever they wanted and had fun using the multimeter, testing their clay. They really seemed to grasp the concept that the electric current flows through the clay, and how it flows depends on the shape and volume of the clay used. We had some other higher-level activities for simulating earth resistance survey, but this activity just clicked so well and they were all really engaged with it!”
Graeme and Finn managed the geophysical equipment with both adult and children participants.
The systems we utilised were all cart-based. Using cart-based magnetometer systems helps to reduce some of the issues you can have when using a number of different operators with manual instruments. Graeme explains this further:
“For example, typically one of the biggest issues is the operator being very magnetic. Using handheld magnetometers can often restrict the number of people who could take an active role in survey, but using a cart system reduces the problem of volunteers being magnetic because of the greater distance between the operator and the instrument. I demonstrated the mag and EM cart, which positions data using a real time GPS stream. The GPS positioning was also beneficial when working with different operators. We were able to collect data on long traverses down the full length of the playing field, which means we didn’t have to worry about the participants walking down specific lines with an even pacing.
What I did not expect was that by using the cart we turned data collection into a more social event. It was a great pleasure seeing people help each other pull the cart whilst passing on what they had just learnt, or even simply walking alongside each other, talking about the site, the history and the area in general. It really gave the participants an opportunity to make new connections within their own community. What’s more it allowed the younger members of the group to contribute; those who would normally be a bit too small to carry a magnetometer were very much enjoying pulling the cart even if they were unaware that they were being helped!”
Finn demonstrated how earth resistance and magnetometry can be collected simultaneously using Geoscan Research’s MSP25 hand pulled cart system:
“We explored the sensitivity of magnetometers by operating the instrument in scan mode to see how it picks up on magnetic clothing items and accessories. We also explored how earth resistance measurements can be collected using towed systems, positioned using the optical encoder wheel system. As with the GPS positioned cart, the encoder wheel positioning helps when using different operators. Demonstrating with different types of kit and non-standard kit was able to get more participants involved. For a particular example, one of the participants really liked the cart system because he was able to get involved collecting data; he said the cart system was much easier and more comfortable than using a traditional earth resistance system where the electrodes are inserted and removed manually.”
Thanks to Big Heritage, Geoscan Research, GNSS Solutions, University of Bradford Archaeological Sciences, and the Centre for Applied Archaeology for Assistance with this project