A. Look at these sentences and decide which object is being described in each one. Use the words in bold to help you. You will find the objects hidden in the word grid at the bottom of the page.

1. The most important part of this object is a strip of two different metals, one on top of the other. As they heat up, both metals expand, but one does it faster than the other. The strip bends and connects with a switch, which turns off the power supply. When the strip cools down, the metals contract and the switch is disconnected. (1 word)

2. This object has several component parts, most of which are made of plastic. A disc inserted into the object spins quickly. At the same time a thin beam of light strikes the disc and converts digital symbols into sounds. These sounds can be increased or decreased in volume by means of a button or dial.(3 words)

3. Liquid and gas are compressed in a hard metal tube. This can be released by pushing or squeezing a button which opens a valve. When the liquid-gas combination leaves the tube and is mixed with oxygen, it rapidly expands. (1 word)

4. This object is mainly made of aluminium. As it moves forward, air flows over two horizontal sections. As it accelerates, a vacuum is formed over the horizontal sections and the object is pulled into the air by the force of this vacuum. (1 word)

5. This object consists of two main parts; one is made mainly of plastic and metal, the other is made mainly of glass. Light enters the glass section and a small door in the device opens up when a button is pressed. At the same time, a smaller window called an aperture adjusts itself to control the amount of light. The light is then absorbed by a sheet of plastic coated in a special chemical. An image is formed and this can then be processed and developed into a two-dimensional paper-based object. (1 word)

6. A sharp blade inside a plastic container rotates very quickly. It chops or grinds anything it touches, which we can then use to produce soup, sauces and dressing. (2 words)

7. This is a very simple object which originated in China. A small piece of paper is lit with a match. It burns away until the flame ignites the chemical compound inside a cardboard tube. The result is a display of light and colour. (1 word)


B. There are nine more objects hidden in the grid. Choose four of them and write a brief description of how they work, using the bold words and expressions above.