Schedule Today: Reading Quiz #3 Salinity Friday: Lab Monday: Reading Quiz #4 Learning Objectives 1) Describe the properties of a water molecule and explain why it is the “universal” solvent. 2) List the four processes that affect salinity and explain how they affect salinity. 3) Explain the relationship between density, temperature, and salinity, and how these create a layered ocean. LO 2. Describe the properties of a water molecule and explain why it is the “universal” solvent. Water (H2O) is a molecule. 2 hydrogen atoms are attached to 1 oxygen atom with a chemical bond H2O is a polar molecule: one side is (-) the other is (+). Polarity allows for….. Water molecules to attract and attach to other water molecules Polarity allows for…. Salinity 1. We all know the ocean is salty. Come up with some ways you could determine the amount of salt that seawater contains 2. Fill in the missing data Mass of seawater sample = 630 g Mass of salt in sample = 22g Mass of water sample = ??? 3. Calculate the salinity, or percent of salt, in this sample. Salinity answers • 1. Evaporate saltwater and weigh the salts. Use conductivity. • 2. Mass of water = 608 g • 3. Salinity = mass of salts (solutes)/mass of seawater (solution) 22 g/630 g = 0.035 or 3.5 percent or 35 per mil (parts per thousand) Salinity is the expression for the amount of dissolved solids (salts) in seawater. Each group member will be assigned a task. Take 5 minutes to research online and then you will report back to your group. 1) What is the average salinity of the oceans? What unit is used to express salinity? 2) What are the main solids (salts) dissolved in seawater. List five. 3) Which two dissolved solids in seawater are the most abundant? When they are combined together, what do they form? 4) What are the main sources for salts in the oceans? Where do the salts come from? LO 2. List the four processes that affect salinity and explain how they affect salinity. How would the salinity of the oceans vary if the continents and oceans each covered 50% of Earth's surface and precipitation and evaporation were similar to present? 1. salinity would be lower than today 2. salinity would be higher than today 3. salinity would be the same as today Think. Pair. Share. Write your answers to the following question on a piece of paper. Would evaporation increase or decrease the salinity of the oceans? Explain your answer. Would precipitation increase or decrease the salinity of the oceans? Explain your answer. Four processes affect salinity Where is precipitation the highest? Where is evaporation the highest? Which location would yield the highest salinity values? 1. 2. 3. 4. E B H F LO 3. Explain the relationship between density, temperature, and salinity, and how these create a layered ocean. 1) Predict what will happen when two parcels of different temperature water are mixed. Share with your neighbor. LO 3. Explain the relationship between density, temperature, and salinity, and how these create a layered ocean. 1) Predict what will happen when two parcels of different water with different salinities are mixed. Share with your neighbor. Which of the following figures shows the correct circulation? The figures show how temperature and density vary with depth. Explain why they are mirror images of each other (write--1 minute) Thermocline Pycnocline Both show temperature variation with depth. (A) is for the equator, (B) is for the Arctic. Why is there a thermocline at A but not at B? Write--1 minute