Science 421a what is Water?

Science 421A

What is Water?
Name:

Use the videos “What is Water?” found on the class website to explore topics in Chemistry, Weather and Ecology. You will need your textbook, class notes and internet research for some problems.

Read “Water, Water Everywhere…”

Answer List the most abundant elements in the universe in order of abundance.

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Answer List the most abundant molecules in the universe in order in order of abundance.

Watch the Video “Method and Madness” from 30:55 – 49:09 to learn more about Henry Cavendish.

Watch and Explain Some consider Henry Cavendish to be an eccentric character, meaning that he was unconventional and slightly strange. In a response, list the ways he was considered eccentric and discuss if you think this characteristic could be an advantage to a scientist?

Research and Describe Brain Cox states that “Cavendish, like many scientists at the time, was fabulously wealthy and so he was able to indulge his curiosity.” Today science is funded in other ways. Research and describe how Canadian research projects in science and technology are funded.

Observe and List Brian Cox performs an experiment that was first designed by Henry Cavendish. When scientists publish reports they will list the materials and methods used in the experiment design so other scientists can check their work. Complete the list of materials that would be used in Cavendish’s report.

Materials Needed:

Observe and Record Scientists can record their observations as qualitative data under a Results section of a report. This is data that is observed but not measured. Write your observations for Brian Cox’s experiment.

Qualitative Results:

Discuss After scientists have their data they will discuss the results and analyze the evidence to draw conclusions. In a scientific report this discussion has its own section and the scientist will use previous scientific knowledge to analyze the results. Using pages 173-174 of the text, discuss the results you observe for Cavendish’s chemical test.

State'>Discussion:

State Cavendish designed another experiment to see how his newly discovered gas, hydrogen, reacted with air. In this experiment Cavendish “created” water. In a chemical reaction what is the term used for substances which are “created” from the reaction? (See pages 173-174)

State What does Brian Cox say “being a scientist is all about?”

Explain Henry Cavendish’s theoretical framework for how water is created was nonsense. So the conclusions he made from his experiments were incorrect. How can he not know what is going on but still provide a useful scientific model for water?

Explain Why do scientists publish their work?

Explain What is the difference between a book and a scientific journal?

Read “The History of the Exploration of Water”

Explain What did Antoine Lavoisier, one the greatest pioneering chemists, get wrong with the building blocks of water?

Explain What component do the majority of common acids contain? (See back of your Periodic Table)

Explain If there is a transfer of protons in acid-base reactions, what method do we use for writing formulas for acids?

Watch the video “What is Water? Part 1” found on the class website and Read Water: The Essential Ingredient

State What is the definition of the term ecosystem?

Answer What is the one thing that unites all life?

State During the video, it shows the percentage of water found in a crab, in human beings and in the human brain to show how much water makes up living things. If the water is removed, what term is used to mean the dry mass of the dry tissue in plants and animals? (See page 38 in your textbook and “Water: The Essential Ingredient”)

Read “Simple but Complex”

Explain When Brian Cox uses the salt and the cup of coffee, he states that the electrons of the hydrogen are “dragged” towards the oxygen’s electron cloud and shared. What type of bond is he referring to? What type of compound is water?

Watch the video “What is Water? Part 2” found on the class website

Properties of Water – Polarity

Observe and Draw Brian Cox shows the polarity of water molecules by using a charged glass rod and silk. The silk strips away electrons from the atoms in the glass rod. Given this, what is the net charge of the rod? What is the net charge of the silk? If water bends towards the glass rod, what side of the water molecule is interacting with the rod?

Draw Create the Lewis Dot diagram for oxygen and hydrogen.

Model and Draw We used a molecular model kit to visualize the water analogy that Professor Cox uses to explain symmetry in your “What is Time” booklet. Use a molecular model kit to build a water molecule and draw the structure below. Label each side with its charge. Build another water molecule and show how two molecules would be stacked together.

Figure 1: One water molecule Figure 2: Two water stacked molecules

Read “Treetops to Teardrops: The magic of Hydrogen Bonds” and use the video “What is Water? Part 2”

Model and Draw Use a molecular model kit to build and draw the molecular compound methane. Add the chemical formula to the Figure description.

Figure 3: Methane ( )

Explain Use your model to explain why methane is not a polar molecule in the figure above.

Properties of Water - Cohesion and Adhesion

Water molecules are highly cohesive (they stick together) and adhesive (they stick to other polar substances) Plants take up and transpire more water than animals do. Xylem raises water up to 350 feet above the ground in some of the largest trees on earth. Figure 4: Cohesion between water molecules and adhesion between water molecules and cell walls allow water to move up trees

Answer What gives water the property that allows it to be draw up so high within the tree?

Observe and Answer Use a graduated cylinder to observe water being drawn up the glass. Observe the dip in the water. What is this dip in the water called? Where do you properly measure a volume of a liquid that is experiencing adhesion to the glass?

Measure and Record



Properties of Water - Solubility

Answer During the video, dissolved substances are being carried by the water in the stream. (You can see some in the picture on the first page of the booklet) List the substances and state if they are ionic or molecular compounds.

Review, Draw and Explain Brian Cox states that because “water molecules are small and polar it can get in amongst other substances, like salts, and rip them apart.” Turn to page 189 in your textbook and draw Figure 4 below. (Don’t forget to label the figure.) Explain what is happening in the figure you’ve created.

State and Answer Write the chemical formula that you see in Figure 4 on page 189. Why does Na have a +1 charge while Cl has a -1 charge?

State What is the definition of solubility?

Watch the video “What is Water? Part 3” found on the class website The Origin of Water

Watch and Answer When Earth was forming 4.54 billion years ago, it was a molten ball of rock. When the inner planet cooled it produced clouds from the released steam but the planet was still hot. What property of water allowed water to remain on the planet?

Read, Think, Write. Today we can often think of extinction as a bad thing. Read “A Brief History of Extinction” on pages 16-17 in your textbook and write an argument from the perspective that extinction is “natural” and we shouldn’t think of it as a “bad thing”. You must have information from the text in your argument.

Read, Think, Write Now write a counter argument which takes the position that extinction can be natural but should be avoided. Use information from pages 10-13 in your argument.

Label Use your textbook to properly label the missing processes in the water cycle.

Figure 6: The water cycle

Read, Think, Write Using your textbook, read about the Nitrogen and the Phosphorous cycle and explain water’s role in each of these processes?

Nitrogen

Phosphorous

State What is the definition for nutrients?

Answer List the ions that are present in the cycles and explain why they are important for life. Use the formulas and the charges in your answer.

Nitrogen

Phosphorous

Answer Complete all sheets on naming compounds and writing formulas. You need to know how to do this for Grade 11 Chemistry.