Properties of Water Lab: What Makes Water Special?
An Investigation of the Liquid that Makes all Life Possible: WATER!
Introduction and Background: Water has some peculiar properties, but because it is the most common liquid on Earth, we typically do not recognize how truly peculiar water really is. Water is everywhere. It's in the air we
breathe. It's in our sink faucets, and it's in every cell of our body. Water is an unusual substance with
special properties. Just think about the wonder of water: How does water rise from the roots of a redwood tree to the very top? How do insects walk on water? Why does ice float rather than sink? Why do people become seriously ill, or die, if they go without liquid for a week or so? How would life in a lake be affected if ice sank and lakes froze from the bottom up?
Purpose: In this lab, we will be investigating and taking a closer look of the water properties that we learned in class by doing each of the 5 stations activity in the lab.
Station 1 Surface Tension (Cohesion and Adhesion) Drop Behavior - Water on Penny Part A
In this station, we will be observing how many drops of water can fit on a penny and the shape of water molecules on a penny
Hypothesis: __________________________________________________________________________________
How many drops of water can pile on a penny before it overflows? Predict in a table like below:
Complete the table!
Table 1. Number of Drops Predicted
person #1
person #2
Person #3
Person #4
total 1-4
average 1-4
Now, let's see how many drops of water you can you place on the surface of a penny before it overflows.
Materials: Coin, water, water dropper
Methods: Drop water from the dropper onto a penny, keeping careful count of each drop.
Data collection and Analysis
Draw a diagram like the one below, showing the shape of the water on the penny after one drop, when the
penny is about half full, and just before it overflows.
Single drop half full drops near overflowing drops
How many drops were you able to place on the surface of the penny before it overflowed?
__________ drops
How is the number of drops different from your prediction, explain what accounts for any difference.
Explain your results in terms of cohesion and hydrogen bond.
____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
_______________________________________________________________________________________________
One Sentence Conclusion:
_______________________________________________________________________________________________
Station 1 Surface Tension & Adhesion Drop Behavior - Water on Penny Part B Effects of Detergent
How many drops do you think this penny will hold after being smeared with detergent, more, less,
or the same as before? Why?
Hypothesis: ______________________________________________________________________________
Exactly how many drops do you think it will hold? Draw this table with a ruler and complete!
Table 2. Prediction of # of Drops of Water on a Penny with Detergent
person #1
person #2
Person #3
Person #4
average
Materials: Coin, detergent, water dropper
Methods:
1. With your finger, spread one small drop of detergent on the surface of a dry penny.
2. Using the same dropper as before, add drops of water to the penny surface. Keep careful
count of the number of drops,
Data collection and analysis
Draw the water on the penny after one drop, about half full, and just before overflowing.
Single drop half full drops near overflowing drops
How many drops were you able to place on the penny before it overflowed this time?
__________ drops
Did the detergent make a difference? Describe the effect of the detergent. _______________________________________________________________________________________________
One sentence Conclusion:
_______________________________________________________________________________________________
*****As ALWAYS Clean-up - Return your station to the condition in which you found it! ...or cleaner!
Station 2: The Climbing Property of Water
Water moves to the tops of tall trees due to capillary action combined with root pressure and
evaporation from the stomata (openings) in the leaves. Water will also climb up paper, and often
the migrating water will carry other molecules along with it. The distance traveled by these other
molecules will vary with their mass and charge.
How fast do you think water would climb a strip of absorbent paper about 1.5cm wide?
about one cm per _______minutes
Hypothesis: ________