1) To learn about the characteristic properties of water. 2) To explain how and why water is necessary for life on Earth. The Properties of Water

Teachers' notes Biology Water The Wonders of Water Basic chemistry and bonding To learn about the properties of water that make life on Earth possible. Subject Topic Title Grade(s) Cross-curricular link(s) Prior knowledge Intended learning outcome(s)

Slide 4: Drag the water molecules to reveal why water is essential. Slide 6: Drag the "Hydrogen Bonds" and "Water Molecule" to the bottom right of the page. The bonds and water molecules are infinitely cloned in order for students to show hydrogen bonding between different water molecules. The water molecule at the top of the page will link to one example of an "answer" for this. From the link page, click on the water molecule at the bottom of the page to return to Slide 7. Slide 7: Allow students time to complete the table on the properties of water. At the end of the allotted time, click on the watering can to link to the "answer" page. There are many answers to these, so allow extra information to be added to the table. Once you have reviewed the "Answer" slide, click on the water molecule at the top of the page to return to the Senteo quiz questions. Lesson notes

The Wonders of Water Why water? Water provides an environment in which many biological reactions take place. Water is involved in and is a common product of many biological reactions. H O H H O H

Water is Polar H2O Water is held together by covalent bonds, but oxygen keeps the electrons around it more than the hydrogens do. The result...oxygen has a slight negative charge while hydrogen has a slight positive charge.

O H H Water is polar. Show how polarity leads to hydrogen bonding between 8 different water molecules. Water molecule Hydrogen bond O H H O H H O H H O H H

Ice is less dense than water High surface tension Strong cohesive properties Universal solvent Thermal properties Properties of Water Capillary Action Hydrogen bonds Polarity

specific heat capacity acts as a thermal regulator

acts as a thermal regulator

1 Water is polar. This means that _____. A the opposite ends of the water molecule have opposite electrical charges Bwater molecules are linear. C water is just one of the many hydrophobic molecules D all of the atoms in a water molecule have equal electronegativities Eall of the above

2 The partial positive and partial negative charges on a water molecule occur because of _____. A the unequal sharing of electrons between the oxygen and the hydrogen atoms in a water molecule B the stability of one atom of a bond but not the other atom Ccovalent bonding Dionic bonding Ehydrogen's high electronegativity

3 In a drop of water molecules, hydrogen bonds form between _____. A two oxygen atoms in different water molecules B the hydrogen atoms in two different water molecules C the hydrogen atom in one water molecule and a oxygen atom in another water molecule D the hydrogens in a single water molecule Enone of the above

4 Cells are made of 70-95% water. In addition, cells are surrounded by water. As a result _____. A the temperature of living things changes relatively slowly B a variety of nutrients are available as dissolved solutes C waste products can be easily removed D dissolved substances can be easily transported within cells or between cells in multicellular organisms Eall of the above

5 You fill a glass of water to just slightly above the rim without it spilling over the glass. What property of water best explains this? Asurface tension Badhesion Cits thermal properties Dice is less dense than water Enone of the above

6 Because molecules of water are farther apart in ice than in liquid form, _____. Aice floats Bice is denser than liquid water Cice expands when it melts D ice vaporizes before liquid water does Eall of the above

7 Nonpolar molecules that do not interact with water molecules are called _____. Acovalent Bhydrophillic Chydrophobic Dnone of the above

O H H Water is polar. Show how polarity leads to hydrogen bonding between 8 different water molecules. O H H O H H O H H O H H O H H O H H O H H O H H Hydrogen bond Water molecule

Ice is less dense than waterIce floats and insulates underlying water High surface tension Water drops form on surfaces and runs off Strong cohesive propertiesWater does not pull apart easily Universal solventMedium for most biological reactions Thermal properties Much energy is necessary to change temperatures in large bodies of water. Properties of Water Capillary Action Cohesion and adhesion allow water to move against gravity in plants/trees. Hydrogen bonds Individually, relatively weak; collectively very strong. PolarityAllows for the formation of hydrogen bonds between other water molecules as well as different molecules.