说课unit13 Senior2.pptVIP

Where there is water, there is life! * The earth is a water planet. properties What properties or characteristics do you know about water? colorless tasteless odorless three forms feeling wet absorbing heat dissolving Fast Reading THE PROPERTIES OF WATER CHEMICAL STRUCTURE SALINITY DENSITY HEAT CAPACITY OCEAN MOTION Find out: water properties Water is a liquid at room temperature, and it has a relatively high freezing point. The reason why water can dissolve most substances on earth is that water has high heat capacity. Like all the other substances, water gets smaller (contract 缩小) when it freezes. Pure water has a higher freezing point and lighter than salt water. The salinity of the earth’s oceans is about 3.5%. When water freezes, its density increases. Other recourses such as oil, gas, gold etc is as precious as a drop of rain. Careful Reading Paragraph 1. What makes the ocean such a great place to live? A.air B.sunshine C.water D.wind Normal state of water: solid liquid gas negative end: + – positive end: + – polar: + – Paragraph 2. H2O:2_______________ + 1____________ = 1___________? Hydrogen Atoms Oxygen Atom H2O Molecule √ √ √ √ √ salinity of sea water: 35‰ 35% Paragraph 3. sea water (salt water) = ________________+ ________________+_________________ ? salinity of sea water affects: ___________and____________________ √ dissolved gases dissolved solids pure water weight freezing point Paragraph 4. Factors of density: ___________and _______________ Unit of density: _____________ = ________________________________ Density of pure water: ____________________= ____________________________________________________________________________ mass volume kg/m3 kilograms per cubic meter 1,000 kg/m3 one cubic mete