7. Read the text "Smart materials". Six sentences have been removed from the text. Choose from sentences a-f the one which fits each gap (1-6).

   	An example of a piezoelectric material in everyday life is the airbag sensor in a car.
   	These fluids can change from a thick fluid (similar to motor oil) to nearly a solid substance within the span of a millisecond when exposed to a magnetic or electric field; the effect can be completely reversed just as quickly when the field is removed.
   	Imagine the range of possibilities, which exist for special materials that have properties scientists can manipulate.
   	ER fluids have mainly been developed for use in clutches and valves, as well as engine mounts designed to reduce noise and vibration in vehicles.
   	The most effective and widely used alloys include NiTi (Nickel - Titanium), CuZnAl, and CuAlNi.
   	Most everyday materials have physical properties, which cannot be significantly altered; for example if oil is heated it will become a little thinner, whereas a smart material with variable viscosity may turn from a fluid which flows easily to a solid.

8. Read the text and answer the questions.

1. What materials are called "smart materials"?

2. Name the properties of smart materials that can be altered.

3. What smart materials do you know?

4. How can piezoelectric materials be used? Give examples.

5. What have you known about electro-rheostatic and magneto-rheostatic materials?

6. What properties do shape memory alloys have?

7. Who researched shape memory alloys? What was the contribution to science?

9. Think of the other heading to the text. Smart materials

Science and technology have made amazing developments in the design of electronics and machinery using standard materials, which do not have particularly special properties (i.e. steel, aluminum, gold). 1 ___. Some such materials have the ability to change shape or size simply by adding a little bit of heat, or to change from a liquid to a solid almost instantly when near a magnet; these materials are called smart materials.

Smart materials have one or more properties that can be dramatically altered. 2 ___. A variety of smart materials already exist. These include piezoelectric materials, magneto-rheostatic materials, electro-rheostatic materials, and shape memory alloys. Some everyday items are already incorporating smart materials (coffeepots, cars, the International Space Station, eyeglasses) and the number of applications for them is growing steadily. Each individual type of smart material has a different property which can be significantly altered, such as viscosity, volume, and conductivity. The property that can be altered influences what types of applications the smart material can be used for.

Piezoelectric materials are most widely used as sensors in different environments. They are often used to measure fluid compositions, fluid density, fluid viscosity, or the force of an impact. 3 ___. The material senses the force of an impact on the car and sends and electric charge deploying the airbag.

Electro-rheostatic (ER) and magneto-rheostatic (MR) materials are fluids, which can experience a dramatic change in their viscosity. 4 __. MR fluids experience a viscosity change when exposed to a magnetic field, while ER fluids experience similar changes in an electric field. The composition of each type of smart fluid varies widely. The most common form of MR fluid consists of tiny iron particles suspended in oil, while ER fluids can be as simple as milk chocolate and oil.

MR fluids are being developed for use in car shocks, damping washing machine vibration, prosthetic limbs, exercise equipment, and surface polishing of machine parts. 5 __ .

Shape memory alloys (SMA's) are metals, which exhibit two very unique properties, pseudo-elasticity, and the shape memory effect. The discovery of the shape-memory effect dates back to 1932 when Swedish researcher Arne Olander first observed the property in gold-cadmium alloys. The same effect was observed in Cu-Zn in the early 1950s. 6 __.

The key to 21st century competitive advantage will be the development of products with increasing levels of functionality. “Smart Materials” will play a critical role in this development, where we define these as materials that form part of a smart structural system that has the capability to sense its environment and the effects thereof and, if truly smart, to respond to that external stimulus via an active control mechanism.