Vernier Software and Technology
Vernier Software & Technology

Water Hardness Study

Figure from experiment 20 from Middle School Science with Vernier

Introduction

When water passes through or over mineral deposits such as limestone, the levels of certain ions present in the water increase greatly and cause the water to be classified as hard water. This term results from the fact that calcium or magnesium ions in water combine with soap molecules. This forms a sticky scum that interferes with soap action and makes it “hard” to get suds. Soft water, such as rainwater or melted snow, is mostly free of these ions. Soft water, when mixed with soap will form suds. A Conductivity Probe can be used to test for ions in water. Hard water, because of the ions it contains, gives a high conductivity reading. Soft water gives a low conductivity reading.

In Part I of this experiment, you will learn how to test water hardness and find the hardness of the tap water in your school. In Part II, you will plan and do a water-hardness study.

Objectives

In this experiment, you will

  • Use soap to find water hardness.
  • Use a Conductivity Probe to find water hardness.
  • Find the hardness of the water in your school.
  • Apply what you learn as you do a water-hardness study.

Sensors and Equipment

This experiment features the following Vernier sensors and equipment.

Option 1

Option 2

Additional Requirements

You may also need an interface and software for data collection. What do I need for data collection?

Standards Correlations

See all standards correlations for Middle School Science with Vernier »

Middle School Science with Vernier

See other experiments from the lab book.

1A Hot Hand
2Heating of Land and Water
3The Greenhouse Effect
4Relative Humidity
5Soil Study
6Absorption of Radiant Energy
7Reflectivity of Light
8Schoolyard Study
9A Good Sock
10What Causes the Seasons?
11Solar Homes
12Ocean Floor Mapping
13Boiling Temperature of Water
14Freezing and Melting of Water
15How Low Can You Go?
15BZiplock Ice Cream
16A Good Cold Pack
17Lemon "Juice"
18Get a Grip!
19Fun with Pressure
20Water Hardness Study
21Diffusion: How Fast?
22A Water Field Study
23Cooling Rates: Shaq vs. Susie
24Yeast Beasts in Action
25Heart Rate and Body Position
26Heart Rate and Exercise
27Mapping a Magnetic Field
28Electromagnets
29Frictional Forces
30First-Class Levers
31Pulleys
32Buoyancy
33Graphing Your Motion
34Speeding Up
35The Indy 100
35BPencil Car
36Crash Dummies
37Falling Objects
38A Speedy Slide

Experiment 20 from Middle School Science with Vernier Lab Book

<em>Middle School Science with Vernier</em> book cover

Included in the Lab Book

Vernier lab books include word-processing files of the student instructions, essential teacher information, suggested answers, sample data and graphs, and more.

Buy the Book

Dev Reference: VST0223

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