Using a drinking straw and a ruler (marked sheet of paper) see if the students can make bubbles with water, milk, skim milk and cream. Which of these makes the best bubbles?
4. Shapes of bubbles
Each group is given some formula “8” bubble mixture and 4 pipe cleaners. Get the students to bend the pipe cleaners into bubble wands with a circle, square, heart and triangle at the end. Get the students to predict the bubble shapes from the 4 pipe cleaner wands. Blow bubbles inside and outside. Record the inside and outside bubble shapes and compare these to the bubble shapes made by blowing through the straw.
Materials: 3 drinking straws trimmed to be a bit shorter than the pipecleaners, 3 half-size straws and 6 pipecleaners.
Put three pipecleaners together and twist them tightly at one end. Slip the 3 drinking straws onto the pipecleaners, bending the pipecleaners at the bottom to form “feet”. Insert the other three pipecleaners through the three half-size straws. Make a triangle with them by twisting their corners together. Twist base and top together at corners, using the “feet”.
Put three of the pipecleaners together and twist them tightly at one end. Make four sets of three twisted pipecleaners. Slip half-straws onto each pipecleaner; bend the pipecleaner to form “feet”. Make each set look like the capital letter “T”, bending the top of the “T” into a right angle. Use two sets of “T”s to form a square with two extended sides. Repeat the procedure with the other two sets. Make one square bottom of the cube by twisting up the extended straws; make the other square the top by twisting the down the extended straws.
What bubble shapes do the students think the “tetrahedral” and “cube” bubble wands will make?
To make bubbles, all sides of the wand must be submerged, the room must be free from drafts and, for the best chance of success, the temperature shouldn’t be too hot, about 22-24 C. Record the bubble shapes inside the tetrahedral and the square bubble wands as well as the shapes of bubbles blown out of these wands.
What shape are the blown bubbles? Why?