a. How has one had an impact on human history?
b. Which sources do you think have a future?
c. What other sources are there?
2. Look at the diagram and answer the questions a and b.
a. What does the diagram show?
b. What types of words are needed to label the diagram? Make some predictions.
3. Label the diagram using no more than TWO words from the passage below for each blank space.
Thomas Newcomen’s steam engine was one of the first devices to use the power of steam for mechanical work. It was originally used to pump water from mines. A boiler, encased in brick and sitting over a coal fire, generated steam, which drove the piston in the open top cylinder above the boiler. When the steam built up, the pressure opened a value allowing the steam to fill the cylinder and push the piston up. When the piston reached the top of the cylinder, the first valve was closed and the second valve opened. This second valve sprayed cold water into the cylinder from a cistern, condensing the steam and creating a vacuum. The air pressure from the open-top cylinder pushed the piston down again, thus pulling the rod down with it. The cycle then repeated itself all over again.
4. Decide if the following sentences about machines are true or false. Use a dictionary to help you. a. A washing machine contains a pump and motor.
b. An air conditioning unit contains a coin and a fan.
c. A photocopier has various components, including rollers and a piston. d. A filter and a tube can be found in a television.
e. A lever and a spring are component parts of a toaster.
f. A valve and a switch can be found in an aerosol spray.
g. Inside a hoover, there is a filter and rotating brushes.
5. Name one object for each of the following components.