Water and It’s properties

1. Waterand It’s properties Sections 2.1-2.4, 2.7-2.18

2. Do Now • 1. How do we rely or use water in our everyday life? • 2. Why is water so valuable?

3. Do Now • 1. Why were our results so scattered yesterday? • 2. When we repeat the penny water/isopropanol today, what would you do differently? • 3. Take out your investigating water properties handout.

4. Do Now • What is chemical formula for water? • What does a water molecule look like? Draw one. • List one property of water from the reading that makes it unique.

5. Objectives • SWBAT identify unique properties of water by performing a water activity and then discussing the results • SWBAT define properties of adhesion, cohesion, polar, nonpolar, and hydrophobic/hydrophillic of water and relate it water activity

6. Water Activity • How many drops of water can you place on the surface of a penny? • How many drops of isopropanolcan you place on the surface of a penny? • Use the handout and create a data table and drawing of the penny.

7. What does Water Look like? • Let’s draw it! • Atom: • Molecule: • Polar:

8. Water Video • We can use the properties of water to explain why the large number of drops can be placed on the surface. • https://www.youtube.com/watch?v=aVmU3CLxvgU

9. DO Now • Explain why the penny makes a dome shape of water in the “drops on a penny” activity. • Explain why a drop of isopropanol causes the dome of water to break.

10. Objectives • SWBAT identify unique properties of water by performing a water activity and then discussing the results • SWBAT define properties of adhesion, cohesion, polar, nonpolar, and hydrophobic/hydrophillic of water and relate it water activity

11. Water contains Polar Covalent bonds • Polar: • Covalent:

12. Water contains hydrogen bonds • -Hydrogen bonds are weak bonds between like molecules • -Partial positive charge attracts a partial negative charge

13. What forms a drop? • -Cohesioncauses water to form drops • Cohesion: attraction of water to water • -Surface tension causes the drops to be spherical • -Adhesion keeps the drops in place • Adhesion: attraction of water to unlike substance

14. Surface Tension: • Water pulls in and attracts itself to form a “film” on its surface to form a drop

15. Water Drop Shapes • -Water has cohesion to itself and forms a nice, round drop • -Round drop on wax paper (not strong adhesion to water) • -As adhesion to glass is stronger and pulls the water, it makes a flatter drop

17. Water on Wax Paper

18. Water coheres to polar, not nonpolar • -“Like adheres to Like” • -Polar molecules will attach to polar and nonpolar will attach to nonpolar • -Water (polar) has no adhesion to wax paper (nonpolar). It rolls right off.

19. Do Now • Explain how to make water not form a drop on a piece of wax. Explain what happens on the molecular level.

20. Objectives • 1. SWBAT continue identify, explain, and apply the properties of water and how they apply to water lab using the water lab. • 2. SWBAT define hydrophillic, hydrophobic, capillary action, and specific heat and apply it to how water is essential to keeping organisms alive using questioning and the chapter 2 powerpoint. • 3. SWBAT answer questions on the properties of water using chapter 2 worksheet.

21. Capillary action: water climbs up small spaces • Because water has both adhesive and cohesive properties, capillary actionis present. • Capillary Action= water’s adhesive property is the cause of capillary action. Water is attracted to some other material and then through cohesion, other water molecules move too as a result of the original adhesion. • Ex: Think water in a straw • Ex: Water moves through trees this way

22. Adhesion to glass and cohesion of water to water

24. Hydrophobic and hydrophilic • -Oil is hydrophobic meaning it does not mix with water. • -Oil is nonpolar and has no hydrogen bonds • -Water is polarand hydrophilic. • - Remember: Like dissolves Like! Food coloring in water Oil in water

25. Amphipathic

26. Water is the Universal Solvent • Solute: substance that is dissolved • Solvent: agent that does the dissolving • Solution: Solute dissolved in solvent • Properties of water that make it an excellent solvent: • -water is polar and can dissolve polar and ionic molecules

27. Video

28. Specific Heat of Water • -Due to hydrogen bonds, water has a better ability to resist temperature change as compared to other substances • -Energy (Heat) must be absorbed to break hydrogen bonds • -Energy is released when hydrogen bonds are formed • Video • Relation to Biology: • -How does this relate to biology?

29. Specific Heat& Life • Relation to Biology: • -Large bodies of water have a fairly constant temperature compared to the atmosphere • -Keeps the water within limits to supply life! • -Your body is made of 66% water… homeostasis • -Coastal areas generally have milder climates • -Large water (oceans) bodies can absorb and release heat • -Heat is absorbed from the sun during warmer times and released • during cooler times to warm the air

30. Water Density • -Ice is less dense than water • -Water vapor is less dense then water • Relation to Biology: • -If ice sank, then lakes • and rivers would freeze • -Killing the aquatic life

31. Water Pollution • Why is water important in biology? • https://www.youtube.com/watch?v=fxZ4IMpM45Y

32. Oil Sheen • -Oil Sheen on water • -Oil on top of water in a thin layer • Pollution: How doe we get rid of it?

33. How to get rid of oil on water • -Detergent breaks up oil into small drops • -Detergents are amphipathic • have both polar and • nonpolar regions