Bubbles, Bubbles, Bubbles
Teacher Instructions (Best for younger students)
Bubbles are air trapped inside a liquid. A bubble can exist because the surface layer of a liquid (usually water) has a certain surface tension, which causes the layer to behave somewhat like an elastic sheet. A common misconception is that soap increases the water's surface tension. Actually soap does the exact opposite, decreasing it to approximately one third the surface tension of pure water. Colors can be seen because of the light diffraction through the soap film.
Instructions:
1) Cover tables with trash bags
2) Group students in pairs or triples.
3) Give each group 4 bowls labeled A-D
4) For younger students, teachers may want to have soap solutions pre-mixed. The older students can mix them themselves.
5) Put 1/3 cup water in each bowl.
6) Bowl A remains only water
7) One spoonful of dish washing soap is put into cups B-D
8) One spoonful of sugar is added to Bowl C
9) 10 drops of glycerin/glycerol is added to Bowl D
10) Have the students make bubble wands from pipe cleaners.
11) Let each group explore which solution creates the best bubble
*Note: Sometimes blowing the bubble back into the bowl works best.
Further experiments: Try different types of soap (i.e. different brands, hand soap, detergent) and compare.
References: http://www.tooter4kids.com/Bubbles/Activities_Recipes.htm
Total time: 30-45 mins
Materials:
20 plastic bowls
trash bags to cover tables
water
one jar dish washing soap
10 table spoons sugar
100 mL Glycerin/glycerol
20 pipe cleaners
Bubbles, Bubbles, Bubbles student worksheet
Name: ______Date: ______
Do all liquids make the same bubble? Let’s find out!
Directions:
1) You will be given bowls labeled A-D.
2) Bowl A has only 1/3 cup water.
3) Bowl B has 1/3 cup water and a spoonful of dish washing soap.
4) Bowl C has 1/3 cup water, a spoonful dish washing soap, and a spoonful of sugar.
5) Bowl D has 1/3 cup water, a spoonful dish washing soap, and 10 drops of glycerol.
6) Make a wand from the pipe cleaner
7) Try making bubbles from each bowl.
Bowl A
Did it make a bubble?
How many? Big? Small? Colors?
Bowl B
Did it make a bubble?
How many? Big? Small? Colors?
Bowl C
Did it make a bubble?
How many? Big? Small? Colors?
Bowl D
Did it make a bubble?
How many? Big? Small? Colors?
Are there any VISIBLE differences in the liquids?
Why do you think they formed different bubbles?