How to make a gallon of bubble-blowing liquid
The Exploratorium, a hands-on science museum in San Francisco, offers this simple recipe for home-made bubble liquid. For longer-lasting bubbles, make the solution ahead of time and let it sit overnight.
You will need:
3/4 cup blue Dawn dishwashing liquid
2 to 3 tablespoons glycerin (available at drugstores)
a container to hold a gallon of liquid
Directions: Pour a gallon of water into a container. A thoroughly rinsed-out one-gallon milk jug works well, but you could also use a bucket and a measuring cup. Now pour out a little more than 3/4ths of a cup of the water, and add the Dawn dishwashing detergent and glycerin. Top off the jug with water.
Glycerin is somewhat expensive ($2.60 for 4 oz. here in Boston), but worth it. The bubbles will be stronger.
Create a giant-bubble blower
This is also from the Exploratorium. You'll need two plastic drinking straws, about three feet of string (we used No. 18 cotton twine), and two pieces of tape. You will also need a shallow pan or tub for the bubble liquid.
Directions: Run the string through both straws and knot it. Push the knot down into one of the straws. Use a strip of tape to form a handle on each straw so you can hold it better.
To use: Stand with your back to the wind. Hold the straws together and dip them into the bubble liquid. Lift them out. Now slowly draw the straws apart until the string is taut. Make sure that the straws are at a 90-degree angle (perpendicular) to the ground. The wind may blow the bubbles for you, or you can blow gently, or sweep the straws through the air to make the bubble.
The trick: You must gently move the straws back together as the bubble is formed, to pinch it off so that it flies free. This takes practice. Experiment!
Note: Do this outside. It's drippy, and your hands are likely to get soapy.