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How can you make Soap Bubbles last longer? Find out with this Experiment
6, 7, 8
Title – LOOKING AT BUBBLES
By – Judy Schneider
Primary Subject – Science
Secondary Subjects – Science
Grade Level – 6 – 8 (adaptable)
SCIENCE PROJECT OF THE WEEK
LOOKING AT BUBBLES
PROBLEM: What things can be added to soap to make the bubbles last longer?
RESEARCH: Read about bubbles. What actually makes up the bubble?
HYPOTHESIS: Do you think adding anything to the soap will make the bubble last longer?
Liquid soap or detergent
Glycerin (use this last)
Clock with a second hand
Two liter bottle with top cut off
Stiff wire – a wire coat hanger will work
Large tray or cookie sheet
1. Each solution will be mixed using one part soap, one part something else from the list above, and six parts water.
2. Try oil first. Measure 100 ml oil, 100 mils soap, and 600 ml water and mix together in a jar.
3. Pour the solution into the 2 liter bottle.
4. Mark a line about 20 cm above the level of the soap solution.
5. Wet the sides of the bottle with the solution and dip the straw into the solution to wet it.
6. Dip the straw into the solution and blow a bubble. Keep blowing until the bubble fills the bottle up to the line you marked. You will have to practice to do this in the least amount of time. The time you take to do this part should be the same through the experiment.
7. Start counting as soon as the bubble reaches the line and stop counting when it pops. Record the time in a data table.
8. Repeat steps 6 and 7 for ten trials.
9. Repeat steps 2 through 8 for each of the substances. Be sure to rinse the 2 liter bottle and straw completely at the end of all the trials for each substance. Do glycerin last so you can use it in the enrichment section.
10. When you have completed all the trials, pour the solution of soap/glycerin/water into the pan.
11. Bend the wire into a 12 inch circle and twist the end to hold it. Bend the handle up.
12. Dip the loop into the soap solution and hold it so it is almost straight up. Hold it so it reflects the light from a ceiling light. Look for the colors in the film of soap.
QUESTIONS: You must answer the following questions to complete the enrichment:
1. Are the colors brighter when the light passes through the bubble or when the light is reflected?
2. In what direction do the lines of color move? Do they always go in the same direction?
3. Where are the lines of color narrowest?
4. What does the film look like on the top just before the bubble pops?
5. The soap film is liquid. Where do you think the soap film is the thickest? Why do you think it is thickest there?
6. What do the colors look like if you hold the loop flat?
7. Does the soap film last longer if it is held horizontally (flat) or vertically (up and down)?
8. A bubble is really three bubbles in one. The outside layers are both soap and the inside layer is water. Can you see the lines of color on both layers of soap? Describe what is happening in both layers.
DATA: Make a data table to record all ten trials for each of the substances you test.
CONCLUSION: This is not optional. You must explain what you learned by doing this activity.
Remember that you must answer the question you asked in your original problem statement.
NOTE: BE SURE TO HAVE YOUR PARENT OR GUARDIAN SIGNS YOUR WORK. PARENTS: YOUR SIGNATURE SHOWS YOUR STUDENT HAS DONE THE WORK.
POSSIBLE HYPOTHESIS Students should make some kind of guess about which of the five substances will help make the bubbles last longest.
POSSIBLE CONCLUSION: Students should discuss the length of time each type of bubble lasted.
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