教案13单元.doc

The water planet Period 3 Reading Teaching Aims and Demands: 1. To help the Ss learn some language knowledge, patterns and language items as well as science knowledge. 2. To develop the Ss ability of reading comprehension through reading activities. 3. To help the Ss understand why water is so important to us and what we can do to protect water. Teaching Difficult Point: 1. Understand each part of the passage. 2. To help improve Ss communicative skills by introducing the proper use of Modal verbs. Teaching Aids: A recorder, some slides Teaching Procedures: Step1: Lead in Ask some questions to make students get to know something about water. Step 2. Fast Reading Ss read the bold words in the passage and understand the structure of the passage. 　　How many parts are there in the passage? Ss read and get the main ideas of each part. 　　Part 1(para1): the properties of water; 　　Part2(Para2): chemical structure of water---H2O 　　Part3(Para3): salinity----- the percentage of salt. 　　Part4(Para4): Density 　　Part5(Para5): heat capacity 　　Part6(Para6-7) Ocean motion Step 3. Careful Reading Read the passage carefully and answer the following questions. 1. What are the properties of water? Water is polar. Water is liquid at room temperature. Water has a relatively high freezing point. Water has density 1,000 kg/m3. Water has high heat capacity. ... 2. What causes water to have such unique properties? －Its molecule form / chemical structure. 3. What is water molecule like? Chemical structure: two hydrogen atoms and one oxygen atom. Different parts of it: a slightly positive end and a slightly negative end, so it is polar. The function of it: it causes water to be able to dissolve both solids and gases, and thats why water can break down nutrients quickly. 4. Do pure water and salt water have the same chemical structure? Does pure water have salinity? Qs: 1) Whats salinity? 2) What is sea / salt water? － A mixture of pure water, dissolved gases and solid