"The Nature of Seawater" Water on Earth PPT Courseware

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"The Nature of Seawater" Water on Earth PPT Courseware

Part One: Explanation of Curriculum Standards

1. Combined with chart information, understand the main factors affecting seawater temperature, salinity and density. (comprehensive thinking)

2. Use chart data to summarize the temporal changes and spatial distribution patterns of seawater temperature, salinity, and density. (regional awareness)

3. Connect with the actual production and life, and analyze the relationship between seawater properties and human activities. (View of harmony between man and earth)

PPT on the properties of sea water, part 2: preview of new knowledge

1. Sea water temperature

1. Influencing factors

(1) Main factors: Ocean heat balance

(2) Other factors: seawater depth, geographical latitude, season, sea and land distribution, atmospheric movement, seawater movement, etc.

2. Distribution rules

3. Influence of sea water temperature

(1) Affects the distribution of marine life

(2) Impact on ocean transportation: Sea areas with higher latitudes have shorter navigation times, and navigation requires icebreaking facilities.

2. Salinity of sea water

1. Concept: Salinity represents the mass fraction of salt substances in seawater, usually expressed in thousandths. The average salinity of the world's oceans is about 35‰.

Small reminder: The salinity of the Red Sea exceeds 40‰, making it the saltiest sea area in the world. The salinity of the Baltic Sea is less than 10‰, making it the sea with the lowest salinity in the world.

2. Salinity distribution of surface seawater in the world’s oceans

Distribution characteristics: The salinity of the world's ocean surface seawater is the highest in the subtropical seas; from the subtropical seas to the equator and the poles, the salinity of the seawater gradually decreases.

3. Main factors affecting seawater salinity

(1) Temperature: The higher the temperature, the higher the salinity.

(2) Comparison between precipitation and evaporation: precipitation is greater than evaporation, and the salinity is lower, and vice versa.

(3) Runoff conditions into the sea: The salinity in the sea area injected by rivers in near-shore areas is low.

4. Impact on human activities

(1) Use seawater to dry salt. Coastal areas with sufficient sunshine and low precipitation are suitable for building salt drying fields.

(2) Use seawater to make alkali and extract resources such as magnesium and bromine.

(3) The stability of salinity affects marine aquaculture.

(4) With the development of science and technology, seawater has become an important supplement to freshwater resources.

A small reminder that the amount of ice formation and melting in high latitudes will affect the salinity of seawater. Sea areas where ice formation occurs have higher salinity, while sea areas where ice melting occurs have low salinity.

PPT on the properties of sea water, part 3: independent detection

1. Judgment of right and wrong

(1) In the vertical direction, the seawater temperature changes greatly. ()

(2) Seawater regulates atmospheric temperature. ()

(3) Low latitude areas have high salinity due to high temperatures and large evaporation. ()

(4) Generally, the seawater near the mouth of a river has low salinity. ()

(5) The emergence of the "sea cliff" phenomenon in the ocean is greatly harmful to submarine navigation. ()

Answer(1)×　(2)√　(3)×　(4)√　(5)√

2. The sea surface temperature in the equatorial region is 30 ℃, and the sea surface temperature in the polar circle is 0 ℃. At the ocean bottom of 4,000 meters, the difference in sea water temperature can reach ()

A.2~3 ℃ B.20 ℃

C.25 ℃ D.30 ℃

It is analyzed that seawater temperature changes with depth. Below 1,000 meters, seawater temperature changes slightly with depth.

Answer A

Seawater density refers to the mass of seawater per unit volume; seawater salinity refers to the ratio of dissolved minerals contained in seawater to the weight of seawater, usually expressed in grams of minerals per kilogram of seawater. The average salinity of the world's oceans is 35‰. Read the picture and complete questions 3~4.

3. The figure shows the temperature of global surface sea water ()

A. Gradually rises from the equator to the poles

B. Increasing from 30° north and south latitude to the equator and the poles respectively

C. Gradually decreases from low latitude to high latitude

D. Increasing from 40° north and south latitude to the equator and the poles respectively

4. It can be seen from the figure that the surface seawater near the equator ()

A.High temperature, low salinity, low density B.High temperature, high salinity, low density

C. Low temperature, low salinity, high density D. Low temperature, high salinity, high density

Analyze question 3: Surface seawater is affected by solar radiation, and the temperature gradually decreases from low latitudes to high latitudes. Question 4: The distribution pattern of seawater salinity is that it decreases from the subtropical sea areas in the southern and northern hemispheres to low and high latitudes on both sides respectively, and the density decreases from high latitudes to low latitudes.

Answer 3.C　4.A

PPT on the nature of sea water, part 4 content: classroom exploration

What are the rules of seawater temperature distribution? What factors are responsible for its changes?

Question exploration

Seawater temperature is a physical quantity that reflects the thermal conditions of seawater. Therefore, its size mainly depends on the income and expenditure of seawater heat. Among them, seawater heat income mainly comes from solar radiation, and seawater heat expenditure mainly refers to the heat consumed by seawater evaporation. The world's ocean heat income and expenditure are basically balanced. However, in different seasons and different sea areas, the heat budget is unbalanced. Figure 1 is a graph showing the changes in average ocean surface temperature with latitude, and Figure 2 is a graph showing changes in water temperature with depth at three observation stations near 170°W in the Pacific Ocean.

Explore with materials:

(1) What are the distribution characteristics of ocean surface temperature shown in Figure 1?

(2) What is the pattern of vertical changes in seawater temperature shown in Figure 2?

(3) Combined with Figure 1, determine the latitude of the three observation stations in Figure 2 and explain the reasons.

Tips (1) Ocean surface temperature decreases from low latitudes to high latitudes.

(2) Seawater temperature changes with depth. The water temperature below 1,000 meters does not change much with depth and remains low.

(3) Among the three observation stations, station ③ has the highest latitude, and station ① has the lowest latitude. Because surface water temperature decreases with increasing latitude.

PPT on the properties of sea water, part 5: In-person testing

1. The factors that can increase both the temperature and salinity of sea water are ()

A. Warm current B. River injection

C.Precipitation D.Evaporation

Analyzing the sea areas where warm currents flow, the seawater temperature and salinity are higher than those at the same latitude.

Answer A

2. Which of the following statements about the density of sea water is correct ()

A. The factors that affect the density of seawater mainly include temperature and salinity, which have nothing to do with depth.

B. Generally speaking, seawater density in sea areas with high temperatures is relatively high.

C. The density of sea water increases with increasing latitude

D. The "sea cliff" phenomenon that appears in the vertical distribution of seawater density will not affect human activities.

Analyze the factors that affect the density of seawater: temperature, salinity and depth; generally speaking, the higher the temperature of the seawater, the lower the density; the "sea cliff" phenomenon will affect submarine activities.

AnswerC

3. Regarding the description of seawater isotherms, the correct statement is ()

A. Isotherms protrude southward near the warm currents in the Northern Hemisphere

B. The isotherm protrudes southward near the cold current in the Southern Hemisphere.

C. The isotherm protrudes northward near the cold current

D. Isotherms bulge toward high latitudes near warm currents

Analysis: The isotherms bulge northward near warm currents in the Northern Hemisphere, the isotherms bulge northward near cold currents in the Southern Hemisphere, and the isotherms bulge southward near cold currents in the Northern Hemisphere.

AnswerD

Keywords: PPT courseware for high school geography required by the People's Education Press is free to download, PPT download of the nature of sea water, PPT download of water on the earth, .PPT format;

For more information about the PPT courseware "Water on Earth and the Properties of Seawater", please click on the "Water on Earth ppt Properties of Seawater" ppt tag.

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"The Nature of Seawater" Water on Earth PPT:

"The Nature of Seawater" Water on Earth PPT Part One Content: Learning Objectives: 1. Understand the main factors that affect the temperature, salinity, and density of seawater. (Key Points) 2. Use chart data to summarize the temporal changes and spatial distribution patterns of seawater temperature, salinity, and density.

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Update Time: 2024-09-09

This template belongs to Geography courseware People's Education Press High School Geography Compulsory Course 1 industry PPT template

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