Right at the entrance to the Ashmolean's newly refurbished and expanded Egyptian galleries you know you are in a different place.
There stand two giant statues of the fertility god Min, one holding his huge erect penis before him. They're incredibly early, dating from around 3300BC. They're not quite what you expect from a monument of a country associated with stiff reverence. Yet they are unmistakably Egyptian in their rigidity and their grandeur. With all that is going on in Egypt, it's worth remembering what a great cultural past this country of the Nile has had. It's not just in the wealth that has been excavated or the monumental size of their sculpture, but that the culture was so pervasive and long-lived that makes it unique.
Which is why it is so compulsive to children as much as adults, and why the opening of the Ashmolean galleries after a £5m refit is such an important event. The museum in Oxford – which claims to be the oldest in Britain, if not Europe – has long held the country's biggest and best collections of ancient Egyptian art after the British Museum. What the Ashmolean has been able to do with this refit is not only bring out a whole range of objects from the basement, but also to take a new view on how to present them.
Over the last generation, there has been a revolution in the way museums approach the arrangement of their objects. Gone is the idea of simply showing interesting things in cases, chronologically or geographically, replaced by the introduction of "concepts" or "themes" to make a story that connects them and provides context. Visitors are meant not only to be impressed by the art but to enter into the civilisation behind it. Two years ago, the museum opened an extension, doubling its gallery space. It used the opportunity to expand its displays, regrouping them on themes of trade and global interconnection, arranging its exhibits by type as well as region.
In the case of these Egyptian galleries in the old building, however, it decided to emphasise the continuity and chronology of a culture that lasted for over 3,000 years and, even when invaded and conquered, never really lost its identity.
You see it from the beginning. The Ashmolean is particularly strong on the pre-dynastic and early dynastic periods. As much in the large objects as the small, in the pottery and exquisite ivories as well as the statuary and ceremonial pieces, you witness the reach for the majestic and the lively that is peculiarly Egyptian. The crowded field of running, fighting animals on the Two Dog Palette and the figure of the Scorpion King on a ceremonial mace head, both 5,000 years old, might as well have come from frescos a couple of thousand years later, so little does the basic imagery change. One of the most powerful figures is also the most contentious. The MacGregor Man, a rigid, bearded figure with a penis shaft before him, is ascribed to the early dynastic period. It's a quite extraordinary figure of tension and stillness. No one can be certain that it isn't a forgery. But in its way it's too original to be a dud, and recent discoveries of similar figures in ivory would back its claim to authenticity.
No such doubts elsewhere as you go chronologically through the six galleries. If limestone and basalt give a hard feel to much of the sculpture, there is an almost friendly – and very rare – figure of a lion done in clay and glaze, and a very human relief of the priest Sheri and his wife Khenteyetka from the Old Kingdom sitting over a table of funerary gifts. It's the fact that you know the names of the people depicted in Egyptian art, scribes as well as kings, and can enjoy the models, furniture and daily domestic items that accompanied them to the grave, that makes the Egyptian civilisation so approachable. That and the writings on papyrus, broken limestone shards and pottery, which the galleries have enabled the Ashmolean to show more fully. "People think that the tombs were all about death," says the assistant curator in charge of the galleries, Liam McNamara. "In fact, they were full of things recording the life of the person buried." He points to one sheet of papyrus. "That's a will, which was included with the woman's burial possessions," he says. "In it, she disinherits her three daughters because they didn't do enough to look after her in her old age." Plus ça change.
Egyptian culture endured, but it did also change. The Ashmolean has a particularly fine collection from Nubian excavations, Egypt's southern neighbour, which, at one time, conquered it. The Shrine of Taharqa, the largest free-standing Pharaonic building in Britain, comes from that period, and shows both the way in which outsiders adopted Egyptian imagery to promote themselves and how they influenced it. More dramatically, under Akhenaten in the 14th-century BC, the country underwent a revolution as the pharaoh abandoned the old gods in favour of a single sun god and radically changed art towards a more naturalistic style. The museum, which participated in the excavations at Tell el-Amarna, has some especially good examples of the elongated figures, diaphanous robes and spontaneity in form which resulted, including figures of Akhenaten and his wife, Nefertiti, and a delightful fresco detail of their two young daughters.
The exhibition ends with the centuries of Greek and Roman domination after Alexander the Great's conquest. The funerary practices and mummification remain, but the bodies now have wood portraits showing the real faces of the dead – Roman realism superimposed on Egyptian formalism. Beside them is the mummy of a small child and, beside it, a modern sculpture by Angela Palmer, based on CT scans of the two-year-old boy drawn on over 100 sheets of glass to give the full three-dimensional effect. Palmer, the artist who brought the giant Amazonian trees to Trafalgar Square in an installation, here uses contemporary technology to recreate the combination of the human and the eternal that makes Egyptian culture so special, as much today as it was then.
The Ancient Egypt and Nubia Galleries, Ashmolean Museum, Oxford (01865 278 002) ongoing