AIRING OUT OUR DIRTY LAUNDRY Kermit Green, Keith Verdi

South Mountain Middle School

BrainstormDoes having a water softener increase the

effectiveness of your laundry detergent?

Background Info Water is considered “hard” when it contains high amounts of dissolved minerals such as calcium and magnesium in it. These dissolved minerals build up in our appliances and interfere with the performance of laundry detergents and other household soaps. Installing a Water Softener in your home will remove these minerals from water and increase the life of your appliances and the effectiveness of soaps/laundry detergents.

Experiment#2Tap H20 vs. Distilled H20

in the Real WorldThis is a repeat of experiment #1 with cotton cloths stained with grass and dirt and ketchup. We will observe each cloth

to see which type of water is better for washing clothes.

J

Gelatin Cube Data Table

Experiment #1Gelatin Cubes in

Tap H20 vs. Distilled H20 We placed equal sized Knox gelatin cubes in both types of water for 17hrs and measured the mass, volume, and density of the cubes.

Set Up ExperimentKnox Gelatin8oz plastic cupsDistilled waterElectronic balanceMetric RulerPlastic KnivesPlastic Spoons100ml Graduated CylinderArm and Hammer Liquid Detergent with Oxi clean

Procedure1.Cut three equal sized Knox gelatin cubes with plastic knife.2.Measure mass with balance.3.Measure the volume using metric ruler.4.Determine Density5.Fill 2 cups with 100ml of each type of water.6.Place one teaspoon of Arm and Hammer in each cup of water and stir.7. Place control in empty cup and remaining cubes in other cups.8.Leave cubes in cups for approx 17hrs and measure mass, volume and density,

Gelatin Cubes

Answer the Question If you wash clothes without a water softener, the laundry detergent has to work “harder” to fight through these minerals and soften the water on its own and usually doesn’t have enough left to properly clean your laundry…unless you use a lot more detergent which doesn’t always get the job done.

AnalogyIt’s kind of like a soccer player who has to jog 5 miles to his game

instead of getting a ride. He uses a lot of energy jogging that he could have used for the game and therefore may not play as well. If he jogs to the game and gets there 2 hours earlier (using more detergent), he

can then rest and build his energy back up, but still may not play as well as he could have had he gotten a ride.

Variables

• Mineral Content of Water• Stain type•Temperature•Agitation time•Detergent brand and type (Liquid vs. powder)

We choose to vary mineral content by comparing tap water to distilled water.

ASK A QUESTION

Will the use of distilled* (soft) water increase the effectiveness of l liquid laundry detergent vs. using tap water?

*Distilled water is soft water without the sodium chloride.

Predict An Outcome

We predict that the laundry detergent will be more effective in the distilled water. As such laundry that is washed in

distilled water should be cleaner than laundry washed in tap water.

Gelatin Cubes Control Tap Water Distilled Water Before/After 17 hours

Before After Before After

Mass in grams

17.14 17.14 19.96 17.15 19.68

Volume in cubic

centimeters

17.13 17.13 21 16.2 22.4

Density in grams per

cubic centimeters

1.0 1.0 .95 1.06 .88

Set Up ExperimentCotton ClothsGeneric Target Brand KetchupPlastic Spoons100ml Graduated CylinderArm and Hammer Liquid Detergent with Oxi clean8oz plastic cups

Procedure1.Fill 4 cups with 100ml of each type of water.2.Fill 2 cups with 100ml of tap water with no detergent, (these cups will be the controls).3.Place one teaspoon of Arm and Hammer in each cup of water and stir.4.Place stained clothes in each type of water.5.Leave clothes in cups for approx 17hrs.6.Stir for 2 minutes each.7.Compare results.

Cloths before soaking Set up of experiment

Results

ResultsThe gelatin cubes increased in mass and volume, but decreased in density. This was due to the detergent causing the proteins to break up and spread out as part of the dissolving process. This happed at a greater rate in the distilled water. If we had left the gelatin in the laundry detergent longer, it would have eventually dissolved.

AnalogyIt’s kind of like a skyscraper that is being imploded. Its volume will increase and density decrease before it is completely cleared and hauled away.

The excess minerals in the tap-water interfere with the action of the enzymes in the laundry detergent. In distilled (soft) water, the enzymes were more effective in breaking down and removing the proteins in the grass and ketchup stains. See pictures above.