What it is made of

Why Iraqi potters chose a tin-oxide glaze for fine ware (D2.6).

Lesson 4 of 4 8 of 8 in the course

Course map

Draft: this lesson was written with AI help and has not yet been read by a human editor.

What your class asks

This lesson asks you to identify the factors that decide whether a material suits a product or a structure. The museum offers one record on glazed ceramics, an opaque white glaze made with tin oxide in ninth-century Iraq. It shows what makers chose; the tests of strength, cost and weather are for your class. 1

Curriculum expectations, with their official codes

  • D2.6 identify the factors that determine the suitability of materials for use in manufacturing a product or constructing a structure

The lesson

Why this material?

List what the maker wanted it to do and what the material had to do in use. Then say which of your points the record supports.

Go deeper

Arthur Lane holds, as the record on his book reports, that the Baghdad potters devised the opaque white tin glaze to imitate white Chinese ware and then painted on it 2 3. The record on Abbasid tin-glazed ware says the surface of Chinese porcelain could not be reproduced with a clear lead glaze over white slip, so the potters of Iraq used a device known earlier to the Egyptians: they mixed tin oxide into a modified lead glaze, making it opaque and white 2. They then painted on the white surface with cobalt blue, copper green, manganese purple and sometimes antimony yellow, paint and glaze being fixed in one firing 2.

Often misunderstood

On a well-purified yellow or pinkish clay, the tin glaze looked deceptively like porcelain 2. The record nevertheless calls what was made in Iraq an imitation: imitations of the white porcelain were found at Samarra alongside the Chinese originals 2.

Think about it

The record says the tin glaze made a clay body look deceptively like porcelain 2. For a bowl used every day, is that appearance enough to judge the material, and what else would you want to test, and why?

Into the museum

Try this

Read about Abbasid tin-glazed ware. Write what the maker wanted, what was added to get it, and one question about how long it would last.

Carry it further

Where this lesson leads in the museum.

Check yourself

Nothing here is marked or sent anywhere. It is for you.

Which of these did you meet in this lesson?

Not in this lesson. Look again at the cards above.

Not in this lesson. Look again at the cards above.

Yes. That is the one from this lesson.

In your own words: what does Abbasid tin-glazed ware have to do with this lesson?

Compare with the card

A glaze that looks like porcelain. The surface of Chinese porcelain could not be reproduced with a clear lead glaze over white slip, so the potters of Iraq mixed tin oxide into a modified lead glaze, making it opaque and white, which on a well-purified yellow or pinkish clay looked deceptively like porcelain. The ware is ninth-century Iraqi pottery. Which properties of clay and glaze mattered to them?

I can now

Notes

  1. 1. Ontario Ministry of Education, The Ontario Curriculum: Science and Technology, Grades 1–8 (2022)
  2. 2. Arthur Lane, Early Islamic Pottery: Mesopotamia, Egypt and Persia, London: Faber and Faber, 1947, p. 28
  3. 3. Arthur Lane, Early Islamic Pottery: Mesopotamia, Egypt and Persia, London: Faber and Faber, 1947, p. 29
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