Shields Formula: The Secret to Moving Stuff!

Discover how a special math trick helps scientists understand how rivers and wind move sand and rocks!

Images

Astrophyllitic agpaite (pegmatitic peralkaline nepheline syenite with astrophyllite) (Khibina Massif, Late Devonian, 362-365 Ma; Kola Peninsula, far-nw Russia) 1

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Crema reparadora de manos - Shield Hand Cream

2024 FIA Formula 3 Silverstone (54041555092)

Astrophyllitic agpaite (peralkaline nepheline syenite with astrophyllite) (Khibina Massif, Late Devonian, 362-365 Ma; Kola Peninsula, far-nw Russia) 2

MU-2 MuMETAL Technical Literature Brochure Cover

Chasuble of green brocaded damask, with embroidered orphreys, probably Italy, 15th century. Shield- or violin-shaped chasuble of mid-green silk damask brocaded in silver gilt; its outer edge is trimmed with a silver-gilt and green fringe; its column orphreys are of red plain-weave silk, embroidered in silver-gilt thread and coloured silks on linen and silk; its lining is of blue glazed linen. The silk damask has a symmetrical pattern created through the ground weave and supplementary brocading wefts. The ground is a classic European pattern of scrolling stems which form compartments. These compartments enclose symmetrical floral motifs in silver gilt thread. The larger of the two motifs is basically round in shape, and looks as if the branches scroll out from a basket; the smaller is much more like a tiny multi-petalled flower. The orphreys comprise a silk band on to which embroidered motifs have been appliqued. Before application to the chasuble, the embroidery was executed on a linen base, a layer of light-coloured yellow silk having been used between the linen and the embroidery for the hands and faces. The colours used are: green (3 shades), blue (3 shades), flesh (2 shades). The stitches used are long and short stitch, satin stitch and couching. The heavy signs of wear on the front orphrey band leave visible the basis on which the embroidery was constructed (linen ground, silk layer and then embroidery, as well as the linen thread padding used for raised areas of the design). The front orphrey has been shortened to fit the current vestment, evident because the lower part of the saint is missing. Iconography: each orphrey bears three female saints who stand within architectural compartments. These compartments are a standard size: 15 inches long x 7 inches wide. The compartments consist of three levels of motifs which throw attention on to the central female figure: a castellated roof over a domed ceiling above the saint's head, 'mid-figure', a background of plain red scattered with embroidered flowers, and on the ground, a tesselated floor. The richness of the materials increases from bottom to top in each compartment. The saints on the back all look in the same direction (towards their right), while those on the front look towards the left. The clothing of the saints follows a formula: each has a halo, wears a gown and mantle and carries the attribute that leads to identification; the halo and mantle are gold, the gown either blue (3 shades) or green (3 shades). The folds of the gown are emphasised by the different shades of the same colour, disposed vertically. On the front orphrey, (from top to bottom) are portrayed St Margaret, St Ursula (?) and three-quarters of a full-length St Barbara; on the back, St Lucy, St Helena (?) and St Catherine of Alexandria (the orphrey has been cut down possibly when the chasuble shape was altered). All but St Helena carry the palm branch that denotes martyrdom, and wear crowns denoting royal birth. St Margaret stands on the dragon (Satan), who swallowed her during her ordeals. St Ursula has an arrow in her hand. St Catherine leans against the wheel on which she was tortured. St Barbara carries the tower in which her father shut her, and St Lucy holds a plate on which her eyes lie. St Helena (canonised 330), mother of Constantine, carries a patriarchal cross, which may suggest the identification in the original accession register. St Ursula is extremely fashionably dressed for about 1420-40, both in terms of her gown with its high, emphasised waistline, and her 'large' and elaborate hair style (Margaret Scott. Medieval Dress and Fashion. British Museum Press, 2007, pp.135 & 139). Silk damask, brocaded with silver-gilt thread, embroidery appliqued.

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Road America - SCCA National Championship Runoffs 9.26.10 - Formula Vee winner #17 Rick Shields

Key Facts

What it Explains

When water or wind can move sediment.

Who Uses It

Scientists and engineers.

What it Moves

Sand, gravel, and small rocks.

Fun Fact

It helps us understand how beaches and sand dunes are made!

What's a Shields Formula?

Imagine a river carrying tiny pebbles downstream. How does it know how much to carry? That's where the Shields formula comes in! It's like a secret code that scientists use to figure out when water or wind is strong enough to pick up and move things like sand, gravel, and even bigger rocks. It helps us understand how beaches are made and how deserts change shape!

Why Does it Matter to Rivers?

Rivers are like busy highways for tiny bits of the Earth! The Shields formula helps us understand how fast a river needs to flow to start moving different sizes of stones. If the water is too slow, the stones just sit there. But if it's fast enough, WHOOSH! The stones get carried away. This is super important for building bridges and making sure rivers don't flood too much.

Wind's Moving Power!

It's not just water that moves things! Wind can also be a powerful mover. Think about a windy day at the beach – you can see sand blowing around. The Shields formula helps scientists understand how strong the wind needs to be to lift sand grains and carry them. This helps us understand how sand dunes are formed in deserts and why some places have lots of sand!

A Cool Science Trick!

So, the Shields formula is a clever math equation that scientists use to predict when things will move. It's like a recipe that tells you the right ingredients (water speed, wind strength) to make something happen (moving sand or rocks). It's a really useful tool for understanding our amazing planet and how it changes all the time!

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Based on content from Wikipedia · Licensed under CC BY-SA 4.0