Name_________________________________________________________________________________ Period: _______________________
Properties of Water Lab
Question: Name as many properties of water as you can:
Procedures:
1. Listen as your teacher describes the location of the 6 stations you will visit. You will work in a group and travel from station to station together.
2. Each station contains directions on how to perform each test. Follow them carefully and write down your data. You may have time to start answering the questions or you may need to move on quickly to the next station.
3. As you finish, start or continue to answer the questions for each. Write a conclusion that contains one sentence about each property.
Data:
Station 1-Heat Capacity
Data: time for air to cool: ____________________ time for water to cool:______________________
Analysis:
1. Heat capacity describes the ability of a substance to gain and lose heat energy. How is water’s heat capacity different than that of air?
2. How might the heat capacity of water affect living things?
3. If our cell were full of air instead of water, what problem would we have in maintaining homeostasis in our body temperature?
Station 2-pH
Data:
Test
pH
Color of litmus paper
Tap water
With 10 drops of acid
Number of drops of base to return to original pH
Record the # of drops and pH:
Analysis:
1. How are acids related to bases?
2. Living things can tolerate only a narrow range of pH, near 7 or neutral. What does this experiment show about changing pH?
3. Our body has a group of chemicals called buffers that help keep pH in the correct range. Why is this necessary?
Station 3: Cohesion, Adhesion and Surface Tension
Data: 1 2 3
Penny with one drop at its highest angle:
Penny with as many drops as it will hold:
Penny with water mound and a small object placed on top:
Drawings:
Analysis:
1. Which test shows the property of surface tension? Why?
2. Which test shows adhesion? Why?
3. Which test shows cohesion? Why?
Station 4: Surface Area and Evaporation
Data: water left in cylinder A__________________ cylinder B__________________ cylinder C____________________
Analysis:
1. Which “leaf” was largest? Which had the most water evaporate?
2. Write a sentence that compares the amount of evaporation with the size or surface area of a leaf:
3. What size leaves would you expect desert plants to have?
Station 5: Water as a Solvent
Data:
Substances (dissolved? Yes/no)
Solvent
Water
Alcohol
Analysis:
1. Which was a better solvent water or alcohol?
2. Do water and alcohol look different? Smell different?
3. Alcohol is composed of non-polar molecules, water is composed of polar molecules. Why might a polar solvent (the water) be better at dissolving most substances?
Station 6: Capillary Action
Data:
Substance
Height in capillary tube
Analysis
1. Rising up the capillary tube requires the liquid to stick to the sides of the tube (adhesion). Another factor, cohesion makes the liquid molecules want to stay together. Which liquid had the most adhesion? Why so you think so?
2. Which had the most cohesion? Why do you think so?
3. In a tree, capillary action can pull water to enormous heights. What would happen if one of the substances you tested were in the place of water?
Conclusion: (one summary statement for each station)
Properties of Water Lab
Question: Name as many properties of water as you can:
Procedures:
1. Listen as your teacher describes the location of the 6 stations you will visit. You will work in a group and travel from station to station together.
2. Each station contains directions on how to perform each test. Follow them carefully and write down your data. You may have time to start answering the questions or you may need to move on quickly to the next station.
3. As you finish, start or continue to answer the questions for each. Write a conclusion that contains one sentence about each property.
Data:
Station 1-Heat Capacity
Data: time for air to cool: ____________________ time for water to cool:______________________
Analysis:
1. Heat capacity describes the ability of a substance to gain and lose heat energy. How is water’s heat capacity different than that of air?
2. How might the heat capacity of water affect living things?
3. If our cell were full of air instead of water, what problem would we have in maintaining homeostasis in our body temperature?
Station 2-pH
Data:
Test
pH
Color of litmus paper
Tap water
With 10 drops of acid
Number of drops of base to return to original pH
Record the # of drops and pH:
Analysis:
1. How are acids related to bases?
2. Living things can tolerate only a narrow range of pH, near 7 or neutral. What does this experiment show about changing pH?
3. Our body has a group of chemicals called buffers that help keep pH in the correct range. Why is this necessary?
Station 3: Cohesion, Adhesion and Surface Tension
Data: 1 2 3
Penny with one drop at its highest angle:
Penny with as many drops as it will hold:
Penny with water mound and a small object placed on top:
Drawings:
Analysis:
1. Which test shows the property of surface tension? Why?
2. Which test shows adhesion? Why?
3. Which test shows cohesion? Why?
Station 4: Surface Area and Evaporation
Data: water left in cylinder A__________________ cylinder B__________________ cylinder C____________________
Analysis:
1. Which “leaf” was largest? Which had the most water evaporate?
2. Write a sentence that compares the amount of evaporation with the size or surface area of a leaf:
3. What size leaves would you expect desert plants to have?
Station 5: Water as a Solvent
Data:
Substances (dissolved? Yes/no)
Solvent
Water
Alcohol
Analysis:
1. Which was a better solvent water or alcohol?
2. Do water and alcohol look different? Smell different?
3. Alcohol is composed of non-polar molecules, water is composed of polar molecules. Why might a polar solvent (the water) be better at dissolving most substances?
Station 6: Capillary Action
Data:
Substance
Height in capillary tube
Analysis
1. Rising up the capillary tube requires the liquid to stick to the sides of the tube (adhesion). Another factor, cohesion makes the liquid molecules want to stay together. Which liquid had the most adhesion? Why so you think so?
2. Which had the most cohesion? Why do you think so?
3. In a tree, capillary action can pull water to enormous heights. What would happen if one of the substances you tested were in the place of water?
Conclusion: (one summary statement for each station)