Imperfections In Solids
Chapter Name : The Solid State |
Sub Topic Code : 102_12_01_10_01 |
Topic Name : Imperfections In Solids |
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Sub Topic Name : Types Of Point Defects |
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Introduction
• Usually a solid consists of an aggregate of large number of small crystals. • Crystalline solids do not have perfect crystals. • These small crystals have defects in them. The defects are irregularities in the arrangement of particles. • This happens when crystallization process occurs at fast or moderate rate. • Defects are of two types: stoichiometric and non-stoichiometric.
Pre-Requisites:
Crystal, crystallization, lattice sites
Activity:
Observe different pieces of the same crystal and notice the changes in them.
Real Life Question:
Why are not all crystals of the same substance the same type?
Key Words / FlashCards
| Key Words | Definitions (pref. in our own words) |
|---|---|
| Crystal defects | Defects are irregularities in the arrangement of particles. |
Learning aids / Gadgets
| Gadgets | How it can be used |
|---|---|
| Marbles | If you closely observe marbles of the same color. You would find that although round in shape, they still appear different. |
Real life uses :
Defects in crystals give rise to impurities. Impurities gives rise to many different variety of crystal structures as well as colors which are used to make jewelry.
Places to visit :
Playground
Practical examples around us
| Examples | Explainations |
|---|---|
| Marbles | Marbles of same colors have different structures from inside. |
What you learn in Theory:
Crystalline solids do not have perfect crystals.
What you learn in Practice:
All crystals of the same substance can have different structures due to defects.