Water (IB Topic A1.1)

Essential Idea(s): Water is the medium of life.

Unit Length: 3 Lessons (+1 AHL)

  Guiding Questions

◊ What physical and chemical properties of water make it essential for life?

◊ What are the challenges and opportunities of water as a habitat?

Materials:

Self-Teaching Slides (SL) / Self-Teaching Slides (AHL)   Quizlet Vocab Set (SL) / Quizlet Vocab Set (AHL)
Teaching Slides (SL)   Notes Template

 

IB Statement(s) and Objective(s)

A1.1.1:  Water as the medium for life

  • Define metabolism
  • Explain why water is regarded as the “medium for life”
  • Outline the evidence that life originated in water

 

A1.1.2:  Hydrogen bonds as a consequence of the polar covalent bonds within water molecules

  • Write the molecular formula for water and draw the atomic structure of the molecule
  • Describe the cause and effect of the polar nature of water
  • Describe hydrogen bonds
  • Contrast covalent and hydrogen bonds

 

A1.1.3:  Cohesion of water molecules due to hydrogen bonding and consequences for organisms

  • Contrast adhesion with cohesion
  • Outline an example of the cohesive properties of water being of benefit to life

 

A1.1.4:  Adhesion of water to materials that are polar or charged and impacts for organisms

  • Define adhesion
  • Define capillary action
  • Outline an example of the adhesive properties of water being of benefit to life
  • Outline the effects of capillary action in soil
  • Outline how capillary action supplies supply plants with mineral nutrients

 

A1.1.5:  Solvent properties of water linked to its role as a medium for metabolism and for transport in plants and animals

  • Explain why water is such a good solvent 
  • State why polar and ionic molecules are hydrophilic
  • State why non-polar and non-ionic molecules are hydrophobic
  • Outline the mechanism of transport in the blood for hydrophilic molecules
  • State if the following molecules are hydrophobic or hydrophilic: Amino acids, cholesterol, fats, oxygen gas (O2)
  • Explain why the functions of some molecules in cells depend on them being hydrophobic and insoluble

 

A1.1.6:  Physical properties of water and the consequences for animals in aquatic habitats

  • Explain three thermal properties of water that are useful to living organisms
  • Outline two example of adaptations that species have to survive in water

Additional Higher Level Topics

A1.1.7 (AHL):  Extraplanetary origin of water on Earth and reasons for its retention

  • Outline hypotheses for the origin of water on Earth (limited to asteroids)
  • Outline the reasons for water retention on Earth (limited to gravity and temperatures)

 

A1.1.8 (AHL):  Relationship between the search for extraterrestrial life and the presence of water

  • Explain the the idea of the “Goldilocks zone” and why it is central to the search for extraterrestrial life
Activities: ⓟ = podcast / ⍰ = inquiry 5 / ⓦ = Write it /  Ӕ = The academy  / Ⓡ = Read it

(Required) Ⓛ: The Water Labs (💁/ 👭max 2)

Have a look at these various mini-labs that explore the various properties of water. Choose a few to actually set up and carry out yourself (most are quite simple to set up / break down). Record or write the answers to the questions that go along with your chosen mini-labs.

 

Ӕ: Water (💁)

Record a Khan Academy-style video explaining the properties of water covered in Topic A1.1 (go here for inspiration). Make sure you explain how these properties make water so essential for life.

 

ⓦ/ⓟ/⍰: Inquiry Questions: The Chemistry of Water (💁)

Write up or record detailed answers to the following inquiry questions. Make sure that you practice clear and concise communication – write, edit, and re-write your responses.

  • Explain why is it so hard to get butter off your hands with just water? (this should be at least a 1-2 paragraph answer).
  • Explain why salt dissolves in water, but a glass marble does not?
  • Draw a diagram to show the network of 4-6 water molecules. Explain HOW and WHY they align themselves in a certain way. Label the diagram and explain the forces that keep them together
  • Explain why many biologists believe that while life elsewhere in the universe is possible, it almost certainly requires water  (AHL)

 

ⓦ/ⓟ: “Follow the Water” – Why the Search for Alien Life Starts with Water (💁 [written] / 👭 [podcast only] max 3)

Some astrophysicists think it is just a matter of time before we discover life on another planet. The search has followed a simple rule: “Follow the water.” Scientists have agreed for decades that where there is life, there must be water. Read this article about our search for extraterrestrial life, and come up with some good inquiry questions to discuss/answer. Here are a few sample questions you could use: 1) What properties of water make it so essential to life?;  2) What places in our own solar system might be home to life?; and 3) If you think it’s possible for life to exist without water, and why.

 

⍰: Q&A on Water (💁/ 👭max 2)

Create a list of 5 or more inquiry questions related to water and its various properties/roles in making life happen. Partner up with another student and answer their questions. You may record this as a podcast or written activity – and submit it to G. Classroom. 

Remember that good inquiry questions are conceptual / open-ended…

Such as: “Why is surface tension of water a vital property for life?; 

NOT: “What is surface tension?” 

If working solo, write out answers to your own questions; if working in pairs, record yourselves asking each other your 5 questions. *Try to write questions that cover as many topics from A1.1 as possible!

Extras:  Water Review Warm-up