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What Makes Water So Special? (14 Favorites)

ACTIVITY in Physical Properties, Polarity, Molecular Structure. Last updated May 30, 2017.


Summary

In this activity, students will become familiar with the special properties of water by completing several activities that investigate the following physical properties: cohesion, adhesion, surface tension, and capillary action.

Grade Level

High School

Objectives

By the end of this activity, students should be able to

  • Explain the meaning of the following terms: cohesion, adhesion, surface tension, and capillary action.
  • Describe the unique behaviors of water molecules, and why they are important.

Chemistry Topics

This activity supports students’ understanding of

  • Physical Properties
  • Properties of water
  • Molecular Structure
  • Polarity

Time

Teacher Preparation: 20-30 minutes

Lesson: 45 minutes

Materials (per group)

  • 1 penny per
  • 1 dropper or disposable pipet
  • 1 square of wax paper (2 x 2 inch)
  • 1 watch glass
  • 1 paperclip
  • 1 petri dish
  • 1 straw
  • Water

Safety

  • Always wear safety goggles when handling chemicals in the lab.
  • Students should wash their hands thoroughly before leaving the lab.
  • When students complete the lab, instruct them how to clean up their materials and dispose of any chemicals.

Teacher Notes

  • If your lab tables have their own sinks, the students can get water from the sink. If you do not have sinks at your lab table, you can provide a cup of water for each lab group.
  • I do the pre-lab together as a whole group, and then let them do the activities in groups of 3-4
  • For the part with the paper clip, it may be helpful to bend a piece of it up to help with setting it down onto the water
  • Use clear straw so that they can see the water rise up the straw

For the Student

Pre-lab QuestionsActivity waterspecial photo1.docx

  • How many hydrogen atoms are in a water molecule?
  • How many oxygen atoms are in a water molecule?
  • What type of bond holds the hydrogen atoms to the oxygen atoms?
  • What makes water polar?

Objective

You will explain the special properties of water.

Materials

  • Penny
  • Dropper
  • Wax paper (2x2 inch)
  • Watch glass
  • Paperclip
  • Petri dish
  • Straw
  • Water

Safety

  • Always wear safety goggles when handling chemicals in the lab.
  • Wash your hands thoroughly before leaving the lab.
  • Follow teacher’s instructions for clean-up of materials.

Procedure

Part 1: Cohesion

  • Predict how many drops of water will fit on the penny and record it in the data table below.
  • Using the dropper, drop water onto the penny, while counting how many drops it holds.
  • Record the number of drops the penny was able to hold before it overflowed.
  • Record observations in your data table.

Part 2: Adhesion

  • Predict how a drop of water will look on the wax paper and draw it in your data table.
  • Predict how a drop of water will look on a watch glass and draw it in your data table.
  • Drop several drops of water onto each surface and record/draw your observations.

Part 3: Surface Tension

  • Put about 10 drops of water into a petri dish, make sure the drops are on top on one another, making one large drop.
  • Carefully place the paperclip on the water—it should float!
  • Record your observations, reactions, or thoughts in your data table.

Part 4: Capillary Action

  • Using the same water and petri dish from the previous activity, carefully set a straw on top of the water drop in the petri dish of water.
  • Record your observations.
  • Place your finger over the top of the straw and pull it out of the petri dish.
  • Record your observations.

Data

Part 1

Predicted Number of Drops


Actual Number of Drops


Observations:

Part 2


Predicted

Actual

Water Drops on Wax Paper



Water Drops on Watch Glass



Part 3

Observations:

Part 4

Observations:

Analysis

  1. Was there a large difference between the number of drops you predicted would fit on the penny and the actual number of drops that fit on the penny?
  2. Based on this activity, describe what you think cohesion means.
  3. What was different about the shape of the water on the wax paper vs the shape of the water on the watch glass?
  4. Based on this activity, describe what you think adhesion means.
  5. The paperclip should be able to float because of surface tension. How would you explain surface tension to a friend?
  6. Explain how capillary action allows water to move up the straw.

Conclusion

  • Using the terms cohesion and surface tension, explain how a water spider is able to walk on water.
  • Using the terms adhesion and capillary action, explain how plants are able to stay hydrated.