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Lesson Plans
Scrubbing Bubbles: Tremendous Triglycerides
OverviewProcedure for teachersStudent Resources and Materials

Prep for Teachers

Before teaching this lesson, make sure that all of your Web sites are bookmarked on all of the computers in your classroom and that all of the necessary links are still valid and running. Cue your videotape to the first segment you are going to use in the learning activity. Make sure that each lab station has all of the necessary components already in place for the start of the lesson. Place all handouts and pencils needed for this lesson on each of the students' desks before class begins.

When using media, provide students with a FOCUS FOR MEDIA INTERACTION, a specific task to complete and/or information to identify during or after viewing a video segment, Web site or other multimedia presentations.

Cue the videotape to the first FOCUS FOR MEDIA INTERACTION cue of a cartoon character standing in front of a bath with the audio cue, "Around 1840, the first bathtubs were imported to North America."

Introductory Activities: Setting the Stage

Shopping on the Internet

As many of us know, the Internet has become much more than just an information research tool. With new dot-com companies popping up on a daily basis and many brick and mortar companies going digital in an effort to lure consumers into purchasing their products, we must be careful of what we see and read on the Internet.

This activity is designed to get your students thinking about what makes one brand of shampoo better than the next. Why should they purchase this brand and not that brand? Can they truly make an informed consumer decision based solely upon what they see and read on the Internet?

Step 1:


Open up your computer's Web browser and select the bookmarked hyperlink/URL for the Pert Shampoo Web site (http://www.pertplus.com/pert_index.asp). Click on the graphic that says "Got Questions?" This will take you to another Web page that deals with the specific types of shampoos that Pert manufactures for various types of hair conditions. Provide your students with a FOCUS FOR MEDIA INTERACTION, asking them to read each "Hair Dilemma" to see what Pert recommends its consumers use to solve their hair problems. Have your students select the shampoo that they think is best for them and their hair condition. Take a random sample of your class's selections to see what style of shampoo they would select based only on what they saw and read at the Web site.

Step 2:


Click on the bookmarked hyperlink/URL for Head and Shoulders Web site (http://www.headandshoulders.com/usa/). At the top of the page, there is a hyperlink button titled "Our Shampoos." Direct your students to click on this hyperlink. Provide your students with a FOCUS FOR MEDIA INTERACTION, asking them to roll their mouse over each different type of shampoo and again read the product description to see which one is best for their particular hair type and condition. Again, take a random sample of your class's selections to see what style of shampoo they would purchase based only on what they read.

Step 3:


Click on the bookmarked hyperlink/URL for the Neutrogena Web site (http://www.neutrogena.com/Home.asp). After the Web site introductory animation, move your mouse to the top left side of the Web page and click on the hyperlinked word "Products." Once the hyperlink rolls down, move your mouse over the hyperlinked word "Hair Care." Once your students are at the Web page for hair care products, provide your students with a FOCUS FOR MEDIA INTERACTION, asking them to once more check out the product descriptions for each of Neutrogena's different shampoos to see which brand they would select from the Neutrogena product line. Again, take a random sample of your class's selections to see what style of shampoo they would purchase based only on what they read.

Step 4:


Ask your students which shampoo selections do they think would do the best job cleaning their hair. How would they be able to determine which shampoo does the best job? Does a $10.00 bottle of shampoo clean better than a $2.00 bottle of shampoo? Does paying more for your shampoo mean you're getting a better product? Do they know how soaps and detergents work? What chemical reaction makes a soap/detergent/shampoo remove dirt/grease/oil from their clothes/skin/hair? After getting your students' reactions to these questions, direct your students to their lab stations for the next Introductory Activity.

Step 5:


In this activity, the students will be exposed to how soaps/detergents react when they are exposed to water for the purpose of cleaning and removing dirt/grease/grime from either their clothes/body/hair.
Procedure:
  • Provide each group with the materials for this activity (listed at right)

  • Direct each group to pour approximately 5cm of milk into their petri dish.

  • Instruct each group to add one drop of each food color to the milk, making sure that they avoid the center of the petri dish and stay as close as possible to the sides of the petri dish. (The best way to describe this step is to tell your students to place one drop at 12 o'clock, one drop at 3 o'clock, one drop at 6 o'clock, and the last drop at 9 o'clock.)

  • Have each group soak one end of their tooth pick in the detergent.

  • Have each group place the detergent soaked end of the toothpick into the center of the petri dish until it touches the bottom of the dish.

  • Ask the students to observe the petri dish and its contents for the next four minutes.

  • Discuss with the class what happened and why. Accept their answers as possible explanations. However, do not clarify any concepts at this point in time.

  • Explain to your students that they are going to view a segment of film that will help them understand more clearly what happened to the milk and food coloring when they placed the detergent laden toothpick into the petri dish. (See Step 7 in the Learning Activity Section of this lesson for a detailed explanation of what chemical reaction takes place in the petri dish.)

Learning Activities

Step 1:

Insert the video Organic Chemistry 2, Episode # 8 "Soap" into the VCR.

Step 2:

Tell your students they are to watch the video segment and see if it helps them understand what happened in the Introductory Activity. Provide your students with a FOCUS FOR MEDIA INTERACTION, asking them to watch the segment to identify why water is such a poor cleansing agent, and to explain the process of dissolving polar molecules. PLAY the tape starting at the visual cue of a cartoon character standing in front of a bath with the audio cue, "Around 1840, the first bathtubs were imported to North America." PAUSE the Video as the narrator says, "In plain water, ring around the collar, a fat, is plain stubborn. It just won't dissolve." Discuss with your students why water alone does not remove the oils from human skin, which are typically found in the ring of a light colored shirt collar. (The fat does not dissolve in the water.)

Discuss with your students if they think that the ring around the shirt collar and the ring around the tub are the same or not and why this phenomena happens to both items that are made of fabric and items that are made from porcelain or plastic.

Step 3:


Provide your students with a FOCUS FOR MEDIA INTERACTION, asking them to listen for the definition of the word "dissolve" and determine why only certain types of molecules dissolve. RESUME the video at the pause point, then PAUSE again at the visual cue of the cartoon image of a shirt in a sink at the narration cue, "Water and oil don't mix." At this point, demonstrate this concept by pouring some oil into a beaker containing water. Shake the beaker or use a stirring rod. Have your students observe what takes place and discuss their observations. (During each attempt, the water and oil do not dissolve in each other.) Discuss with your students why they think oil and water do not mix. What makes them continually want to separate?

Step 4:


Provide your students with a FOCUS FOR MEDIA INTERACTION, asking them to watch the next video segment and look for the molecular structure of the fat molecule. They are to complete the drawing on the worksheet at their individual desks. RESUME the tape at the last pause point, then PAUSE the video at the visual cue of a fat molecule surrounded by water molecules at the narration cue, "Both fat and oils are non-polar, and as such cannot participate in hydrogen-bonding with water." Discuss with your students the difference between saturated and unsaturated fats as discussed in the film. If your students do not make this connection the first time, just REWIND the segment and replay it for further clarification. (The fat molecules have a long hydrocarbon chain with no double bonds and are said to be saturated with hydrogen. The oil and grease molecules have a varying number of double bonds, and are identified as unsaturated.) Give the students an opportunity finish their drawings and to label their drawing of the fat/oil molecule.

Step 5:

Provide your students with a FOCUS FOR MEDIA INTERACTION, asking them to determine the effect that detergents have on fat molecules. They will need to explain how the fat molecules become "dissolvable" or emulsified in water. (An emulsion is a suspension of microscopic oil droplets in water.) RESUME the video at the pause point, then PAUSE at the visual cue of the soap molecule at the narration cue, "The soap molecule has an ionic head and a non-polar tail." At this point, discuss with your students the transition of the fat molecule to a soap molecule with the addition of a base of sodium hydroxide. (The soap molecule has a hydrophobic region, which is hydrocarbon in structure and non-water attracting in its character, and a hydrophilic region, which will dissolve in water.) Allow your students ample time to complete the worksheet by labeling the soap and detergent molecules.

Step 6:

Provide your students with the next FOCUS FOR MEDIA INTERACTION, asking them to look for the formation of micelles and to be ready to explain how the dirt is "swept away." RESUME the tape at the last pause point and STOP the tape at when the narration says, "It is converted into discrete, suspended blocks, transported by water, and swept away." Check for comprehension, and discuss with your students how soap molecules clean. Have your students write down their ideas and descriptions in their notebooks or on the back of Worksheet #1.

Step 7:

Refocus your class's attention to the Introductory Activity. Discuss with your class what happened to the food coloring when a detergent was introduced to the milk. (Currents of color quickly move out in all directions from the center of the petri dish. Swirling movements of separate colors are seen across the surface of the milk during the first two minutes. Within the next two minutes, the colors begin to mix and form a final gray mixture.) Discuss with your students that the colors remain separate at first because of the fat in the milk. These fatty drops do not mix with the watery food coloring, therefore the colors are kept apart. The colors move outward due to the surface water molecules' pull on the molecules of color with an equal force in all directions. By placing the soap in the center of the petri dish, they weakened the pull of the water molecules in the center of the dish, and the stronger clinging water molecules on the opposite sides of the color molecules pulled them across the surface of the water towards the edge of the petri dish. The soap or detergent, a surfactant, lowered the surface tension of the water. As the drops of fat are broken into smaller particles, micelles, by the detergent, they spread out, allowing more of the food coloring and milk to mix.


Cross-Curricilar Extensions

Step 1:

Explain to your students that the ability of certain molecules to act as a cleaning agent has a direct relationship to their molecular structure, just like what we saw in the learning activity. Shampoos are cleaning agents and can be tested to obtain empirical data about their characteristics and relative effectiveness as a cleaner. A number of variables will be tested, including the pH levels, flash volumes, foam retention, dispersion, and the viscosity of each shampoo selected earlier. From their studies, the class can begin to draw a limited number of scientific conclusions. The open-endedness of this hands-on activity allows them to explore as many different shampoos as they desire. (If you like, have your students bring in their favorite shampoo. This will provide the class with a adequate sampling with which the students may begin their investigation.)

Step 2:

Direct your students to break up into their lab groups and arrange the their lab stations for the next experiment.

Step 3:

Distribute the Worksheet #2 to each student in the class. Instruct your students to follow the steps on Worksheet #2. This lab is designed so that your students can collect empirical data about the character and relative effectiveness of various shampoos. It is important as you circulate through the room that you remind your students that the data from each group experiment can be compared, and a consumer effectiveness report can be prepared on each of the various shampoos tested. These results can be published either as a computer-generated report or as a student designed and created consumer information Web site.

Step 4:

After each group has finished testing and recording the results for their five shampoos, have them once again return to their computers and click on the bookmarked hyperlink/URL for the Street Cents Web site (http://www.halifax.cbc.ca/streetcents/show/more/show_08_00/shampoo.html#link8). Provide your students with a FOCUS FOR MEDIA INTERACTION, asking your students to read over the following Web site paying particular attention to information about surfactants in shampoos and what each one does. Ask them to look at their results for the lab portion of this activity and determine, based on the ingredients of their shampoos, which ones truly are worth the expenditure and which ones are not. Have them determine, based on their reading and the ingredients listed on each shampoo bottle, which shampoos are and are not harmful to their hair even if the companies say the product is meant to treat their hair condition.

Step 5:

At the bottom of the Street Cents Web page, there is a small blurb about a Consumer Reports test and which shampoos their test has determined to be the best on the market. If you desire, have those shampoos on hand and have each group perform the testing phase all over again. This time, each group could do one shampoo and report their results back to the class.


Cross-Curricilar Extensions

ART
Students can invent their own brands of soap. Using solid vegetable shortening and a 250ml beaker, add 10ml of ethanol and 5ml of 6M NaOH solution (1.2 gms of NaOH in 5ml of water). Using a hotplate, heat the mixture and stir for 15 minutes. While heating, students can add ingredients to the soap: color, scent, or even plastic surprises.

SOCIAL STUDIES
Research soapmaking in the 19th century and early 20th century. Write down a systematic procedure for making soap.

FAMILY CONSUMER SCIENCES AND FINE ARTS
Have students create their own bars of soap using the systematic procedure they discovered during their social studies class.
Have students make various shaped bars of soaps using baking molds.

LANGUAGE ARTS
Students can keep a journal of all the foods that they eat for one week. They can then analyze what percentage of their weekly diet consists of fat.
Have your students write a pamphlet on the health risks related to a high fat diet.
Have your students research a female scientist, and write a one-page report on their life and contributions to the concepts covered in this lesson.
Female Scientists

  • Jacqueline K Barton
  • Emma Perry Carr
  • Rachel L. Carson
  • Gertrude T Cori
  • Stephanie Kwolek
  • Kathleen Nauss
  • Brigit Vennesland

Community Connections
  • Students can visit a local eatery and interview the kitchen staff to see how they clean the kitchen equipment on a daily basis.

  • Students can visit the school cafeteria to learn how they clean the utensils and cafeteria trays and learn about the cleaning equipment used in the kitchen.

  • Visit a local advertising company to investigate how marketing agencies market their products in an effort to entice consumers to purchase their clients' products.

  • Invite a local doctor or surgeon to the classroom to speak to your students about cleaning materials and procedures used in hospitals and doctor's offices to ensure clean and sterile environments for his/her patients.

  • Students can bring in ocean water to see if soap is as effective in salt water as it is in natural water.

  • Students can speak with the school's custodians about how various areas of the school building are cleaned differently and what types of cleaning solutions and procedures are used to keep their school clean.