Submitting Organization: Community Resources for Science
Grade Levels: 5th Grade
Subject Area: Science
Standards Alignment: Next Generation Science Standards
Physical Science: 5. Structure and Properties of Matter 5-PS1-3. Make observations and measurements to identify materials based on their properties
Description of the Activity: Students use notebook to note predictions and results of each step.
- On a piece of wax paper with edges folded up, students place one drop of water and closely observe the drop.
- Next, students place a drop of oil on the wax paper, and observe and note differences and similarities. Tilt the paper until the drops touch. What happens?
- Predict what will happen if a drop of soap is added? What will happen to the water drop? The oil drop?
- After noting prediction, place drop of soap onto wax paper, bring into contact with oil and with water.
- What happens? Why? Draw or describe results.
Discussion Questions: Using their notes, students share their sketches, describing results and observations for each step of the activity.
- Describe the water droplet and the oil droplet?
- Are they the same or different?
- Why are oil and water drops shaped that way? (Because water is polar; water molecules are attracted to each other. Oil isn’t.)
- Why don’t oil and water mix? (Because water is polar; water molecules are attracted to each other. Oil isn’t.)
- Why does soap flatten the water bubble? (The “tail” of the soap droplet is hydrophobic, while the “head” is hydrophilic — they react in opposite ways to the water and to the oil.)
- Wax paper, 5 inch square (approx), 1 per student
- Droppers (one per table group)
- Small cup water, small cup oil, small cup dish soap (1 each per table group, 1-2 oz per liquid)
Link to further resources: http://www.crscience.org/lessonplans/5_Bowring_ChemistryofSoap_1011.pdf