English Unlimited HTL 1, Schulbuch

Read the description of the barometer and complete it with the words in the boxes. Barometers are used to measure atmospheric (1) , and have been in use since the 17 th century. Early barometers used (2) , but were soon replaced with the mechanical barometers seen here. They have a sealed, partially evacuated metal box inside. As the air pressure rises or falls, the box either (3) or flexes outward. The box is attached to a metal spring and, as the box responds to the changes in air pressure, the spring (4) or contracts. This movement is (5) with a system of levers, which are then attached to a chain. The chain moves the pointer on the dial, which is (6) (marked with numbers) so you can read the air pressure (7) . Look at the diagram and label the parts with the words in the boxes. Media task . Choose one measuring instrument from the list. ■■ tape measure ■■ milometer (AE: odometer) ■■ altimeter ■■ laser range finder ■■ vernier callipers ■■ barometer ■■ tyre-pressure gauge ■■ measuring cup ■■ analogue scales ■■ drawing compass ■■ digital fever thermometer ■■ stopwatch Go on the internet and research the answers to the following questions. ■■ What is it used for? ■■ What parts does it consist of? ■■ How much does it cost? Present your findings to the class in the next lesson (2–3 minutes). Make sure that you know how to pronounce the name of the instrument. Use phrases like: With a … you can … It is used to measure … Before … , you must … It consists of … The display shows … It is very precise / shockproof / water-resistant … It is made of plastic / metal … It costs … 30 accurately calibrated compresses pressure mercury expands amplified b pointer evacuated box levers chain metal spring 1 3 5 2 4 31 a b c 124 Language skills Extras Explore 9 Are you OK? Nur zu Prüfzwecken – Eigentum des Verlags öbv