Differential Weathering

O‘zbekcha versiya

Built in the early 17th century, the Nadir Divan-begi Madrasah has been exposed to natural weathering processes for around 400 years.

Weathering is the natural breakdown and alteration of rock or mineral material at or near Earth's surface. Unlike erosion, weathering changes the material in place without transporting it away.

Water can enter pores, cracks and joints, while temperature changes cause materials to expand and contract. Dissolved substances in water can also contribute to chemical weathering.

Not all materials weather at the same rate. Brick, mortar and glazed surfaces have different porosity, hardness and mineral composition. As a result, materials exposed to the same environment can deteriorate at different rates. This is called differential weathering.

The Madrasah provides a good opportunity to observe this process directly. Please base your observations on the original exposed surfaces and avoid obviously restored areas.

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1. Find a visibly weathered area of the Madrasah. What signs of weathering can you observe? Describe one feature such as cracks, flaking, loss of material or discoloration.
2. Compare two different surfaces, such as brick, mortar or decorated areas. Which appears more affected by weathering, and what differences can you observe?
3. Find an area where two different materials meet and one appears to have weathered more strongly than the other. Why might these two materials weather at different rates even though they are exposed to the same environment?
4. Water is an important agent of weathering. How can water contribute to the deterioration of the materials at the Madrasah? Give one physical or chemical process.
5. Take a photo of yourself at the location and add it to your log.

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ENGLISH VERSION

XVII asr boshlarida qurilgan Nodir Devonbegi madrasasi taxminan 400 yil davomida tabiiy nurash jarayonlariga duchor bo‘lib kelmoqda.

Nurash — bu Yer yuzasida yoki unga yaqin joyda tog‘ jinslari yoki mineral materiallarning tabiiy ravishda parchalanishi va o‘zgarishidir. Eroziyadan farqli o‘laroq, nurash jarayonida material boshqa joyga ko‘chirilmaydi, balki o‘z o‘rnida o‘zgarishga uchraydi.

Suv materiallardagi g‘ovak, yoriq va choklarga kirib borishi mumkin, harorat o‘zgarishi esa materiallarning kengayishi va qisqarishiga sabab bo‘ladi. Suvda erigan moddalar ham kimyoviy nurash jarayoniga ta’sir ko‘rsatishi mumkin.

Barcha materiallar ham bir xil tezlikda nuramaydi. G‘isht, qorishma va sirlangan yuzalar turlicha g‘ovaklik, qattiqlik va mineral tarkibga ega. Shu sababli, bir xil muhit ta’sirida bo‘lgan materiallar turlicha tezlikda yemirilishi mumkin. Bu hodisa differensial nurash deb ataladi.

Madrasa ushbu jarayonni bevosita kuzatish uchun yaxshi imkoniyat yaratadi. Kuzatuvlaringizni asl, ochiq qolgan yuzalar asosida olib boring va qayta ta’mirlangani yaqqol ko‘rinib turgan qismlardan saqlaning.

Ushbu EarthCache topshirig‘ini bajarish

Ushbu EarthCache bo‘yicha qayd yozuvi qoldirish uchun, iltimos, quyidagi savollarga javob bering va javoblaringizni menga yuboring (elektron pochta yoki xabar markazi orqali):

1. Ochiq devorlardagi bir nechta g‘ishtni ko‘zdan kechiring. Qanday rang farqlarini kuzatishingiz mumkin? Ikki misol keltiring.
2. Qizg‘ish g‘isht hamda och yoki sarg‘ish g‘ishtni toping. Ularning rangi va sirt ko‘rinishi qanday farq qiladi?
3. Temir saqlovchi minerallar pishirish jarayonidagi kimyoviy holatiga qarab turli ranglarni hosil qilishi mumkin. Siz qaysi rangni oksidlangan temir bilan ko‘proq bog‘lagan bo‘lardingiz: qizg‘ishmi yoki kulrang/to‘q rangnimi? Nima uchun?
4. G‘ishtlar pishirilishidan oldin minerallarni o‘z ichiga olgan loydan tayyorlangan. Nima uchun bir xil xomashyodan tayyorlangan g‘ishtlar yakunda har xil rangga ega bo‘lishi mumkin?
5. Ushbu joyda o‘zingizning suratingizni oling va uni hisobotingizga (logingizga) ilova qiling.

Iltimos, javoblaringizni topshiriqni qayd etishdan (log yozishdan) oldin yoki darhol keyin menga yuboring. Tashrifingizni qayd etish uchun mening ruxsatimni kutishingiz shart emas. Javoblaringizda biron-bir muammo bo‘lsa, siz bilan bog‘lanaman.