Archaeology on television can seem like an activity for geeks in white coats and blokes in over-sized jumpers. But its range of activities is so wide – from laboratory to museum, from excavation to historic building – almost anyone can find a welcome somewhere. Master our quick guide, and you will soon sound like a proper digger.

Key concepts

Site: A place where something happened in the past that could be or is the subject of excavation.

Evaluation: Research, including the digging of narrow "trial trenches" (often with machines), to establish the quality of preservation at a site and its significance (Time Team digs are often described as evaluations).

Excavation: The real McCoy, from a few days digging in a farmyard, to years investigating 75 hectares (185 acres) by 80 field archaeologists, with a laboratory and 27 computers on site, prior to the opening of Heathrow Terminal 5.

Fill: Disturbed earth, rubble, etc, found beneath the surface, indicative of human activity.

Natural: Undisturbed geological strata at the bottom of the site.

Spoil: Excavated dirt that supposedly contains no finds (it ends up being dumped on the spoilheap).

Find: Any item worthy of individual attention, such as a coin, piece of pottery or animal bone.

Feature: Anything such as a pit, ditch or stain in the ground, typically with an origin and purpose that is not immediately obvious.

Structure: A former building or erection of any kind, indicated by post holes, wall foundations, etc.

Layer: Deposit of material that seems to have been made during one particular time.

Context: Perhaps the most important concept. Something distinct in the ground, such as a layer or feature that represents a definable unit of time, is known as a context; a grave, for example, might have a context number for the grave pit that was dug, another for the coffin and body placed there, and a third for the fill (the backfilling of the grave). Relationships between contexts (for example, that between one grave and another it was dug through) are recorded in a matrix, which on large urban sites can be extremely complex.

Stratigraphy: the science of unravelling how everything on the site got there and in what order (sequence), through study of finds, structures and contexts.

Key personal equipment

● Hard hat, high-visibility jacket and steel-toed boots (commercial excavation).

● Sunglasses, sunhat and tanning lotion (university excavation).

● Pointing trowel: first recorded archaeological use in 1808, since when it has been an essential mark of pride, professionalism and one-upmanship – the more worn and less useful the trowel, the more prestigious.

Key stages of a dig

1. Deciding why, where and when to dig. This can take months or years, with the initial impetus likely to be a threat to a known or suspected site (eg from coastal erosion or office development), or a research inquiry at an unthreatened site (eg Stonehenge). Often involves planning and permit issues, and always requires finding funds (from the developer, or grants).

2. Running the dig – the easy bit. Not all jobs mean you get cold, wet, bruised, grazed and dirty, but most do. Education and outreach (letting the public in) is seen as essential on large digs, though commercial sites can be secretive.

3. Post-excavation. The longest and most expensive stage, in which the records, finds and scientific samples are sorted and analysed, and hopefully used to produce a narrative of the site's history that will be published.

Why is everything old underground?

Aside from structures that are still standing, most everyday things of past lives have all disappeared; the exceptions are items that somehow became embedded in the ground and preserved.

If someone in the past dug down, for example to make a grave, a pit for food storage or a drainage ditch, sooner or later the hole will have been filled in. A skilled archaeologist can identify the ancient excavation and the fill it contains, which will often include deliberately buried or discarded artefacts and other remains.

Ancient land surfaces (much sought after by archaeologists) can be preserved by accidental burial. This can occur artificially (when a burial mound is raised, it preserves the surface on which it stands: at Silbury Hill, the huge neolithic mound in Wiltshire, even the grass survives, preserved by the lack of oxygen); or naturally, such as beneath blown sand or mudflows (at Boxgrove, West Sussex, a massive cliff fall 470,000 years ago buried the ground on which early humans sat around a water hole waiting for large game).

Anything on the ground surface left alone for long enough will sink down 10–30cm beneath an accumulation of earthworm casts. Charles Darwin demonstrated this process in his best-selling book of his lifetime, Vegetable Mould & Earth-worms (1881).

What to say when you visit a dig

● "I can't believe you sorted out the relationship between context 375B and the fill of cut 233. That took real skill."

● "I saw your outreach presentation on YouTube – cool, dude."

● "I've never seen such a worn trowel."

● "Can I buy you a pint?"

What not to say when you visit a dig

● "I've brought this stone I found in my garden. I'm sure it's a prehistoric tool – look."

● (As you clean a smear from your Manolos with a wet wipe) "I'd love to be an archaeologist, it's so romantic."

● "Are you looking for dinosaurs?"

● "Found anything yet?"

How can I get started?

Many archaeologists are keen to share their experiences with others, and encourage visits. The Council for British Archaeology promotes appreciation and care of the historic environment. Its website lists excavations, conferences and advice on how to get involved. I Love the Past reviews historic properties, museums and excavations. The magazines British Archaeology and Current Archaeology regularly feature excavations.

Look out for Portable Antiquities Scheme meetings in your area (England and Wales only), when archaeologists linked to the British Museum hold public "finds days".

Mike Pitts is editor of British Archaeology