Unit 13 The water planet教學設計
④ experiment 4 illustrates some of the differences between salt water and fresh water.
step3.speaking
1. pre-speaking
1) do you agree with the saying “without water, life would not exist.”?
2) so not only you and i agree with this opinion, but also the united nations hold the same view. and that’s why we have world water day.
q: is there anyone who knows when it is? － mar. 22
3) brief background information about world water day: world day for water is established by the united nations general assembly's resolution 47/193 of 22 december 1992. it is a unique occasion to remind everybody that concrete efforts to provide clean drinking water and increase awareness world-wide of the problems and of the solutions, can help make the difference.
4) last year we witnessed some great disasters such as the typhoon “yunna” and the tsunami in the india ocean. what a coincidence that the theme for world water day was “water and disaster”. world water day will be guided by the upcoming water decade's theme "water for life". it will be the starting day for this international decade for action, "water for life".
2. while-speaking
1) to some extent, the existence of world water day also implies that human beings cannot live without water. why? can you tell how water is being used in our life? give some examples.
－electricity, agriculture, home use, industry, transport, entertainment, etc.
2) look at the first picture (“electricity”) in the textbook and talk about it.
the water is being used to generate electricity. building up behind a high dam, water accumulates potential energy (勢能). this is transformed into mechanical energy when the water rushes down. it is a good way to use water because water is renewable green energy. it will never run out if only we use it properly and generating electricity by using water is a better way to protect the environment than others. however, it takes a great sum of money and a long period of time to build a dam and prepare all the required equipment. since nowadays electricity has already been an indispensable part of our life, most people benefit from using water in this way.
3) group work. divide students into several groups with six in each. each one takes charge of one picture.
when discussing each picture, please think about the following questions:
how is water being used?
what property of water enables it to be used in this way?
why do we use water in this way?