Field Trip Notes
When Wanda's favorite singer, Molly Cule, comes to town, she chooses Ms. Frizzle's class to wash her famous car. The kids clean the car top to bottom, but Molly insists they missed a spot. Only when they shrink small enough to see molecules can they clean the car down to the very last bit - but time is running out, and they need a molecular miracle to get the job done before Molly's concert begins.

Matchmaker, Matchmaker

Going Hands-On

Time: 50 minutes
Group Size: 4

Ralphie discovers that soap and water slip grease and grime away because of the special characteristics of soap molecules. Your kids investigate some characteristics of oil, water, and soap.

What You Need

• Dishpan of water
• Paper towels
• Liquid detergent
• Copies of MATCHMAKER, MATCHMAKER page

For each group:

• 2 tumblers of water
• 2 tablespoons cooking oil
• 1 tablespoon liquid detergent
• Spoon

Talk About It

Pass around samples of oil, water, and liquid soap. Ask: What are some characteristics of water? Oil? Soap? List responses. Ask: Do the teeniest-tiniest bits (molecules) of these things determine these properties? (yes)

What To Do

1. Let kids touch the substances. Ask: How do they feel? Is how they feel a characteristic? (yes) 
2. Have kids dip a finger in oil and then try to rinse it off with water alone. Ask: Does the oil come off? Hocould we remove it? 
3. During the activity, students will discover that soap and water mix, while oil floats on top of water. Challenge kids: Can you mix oil and water? Record kids’ ideas. If possible, let them experiment with some of their ideas.
4. After kids add soap to the oil and water, ask: What did the soap do to the oil and water? (Soap mixes oil and water because on end of the soap molecule is water-loving, while the other clings to oil. Stirring in soap creates a cloudy suspension of tiny oil droplets surrounded by soap molecules - an emulsion.) 
5. Ask: Why do soap and water clean oil and grime? (The oil-loving end of the soap molecule surrounds and lifts the oil; water rinses it away.)

Next Stop

Draw timelines of the kids’ rocks. Decide on a time scale, and let kids give their ideas for: where their rock was a very long time ago and what it looked like; where it was found; where it will be and how it will look a long time in the future.