Sherri Sotello
6th Grade Teacher
Tustumena Elementary
Mile 110.5 Sterling Highway
Kasilof, Alaska 99610
Objective
The students will be able to:
work in a group to build a hot air balloon
make observations and inferences when flying balloons
make predictions
participate in a roleplay to formulate a concept of density as it pertains to like molecules
explore how relative density can affect how an object acts
communicate the scientific principles involved in how a hot air balloon rises and falls
Materials
Procedures
Activity #1: See attached directions for constructing and flying hot air balloons.
Demonstration: Put hot water in one clear glass container and cold water in the other. Drop one or two drops of food coloring in each. The food coloring in the hot water will mix more quickly than the food coloring in the cold water. This demonstration illustrates that warm molecules move more quickly than cooler molecules.
Activity #2: Using tape, mark off an area about four square feet. Have as many students fit in the square as possible. These students represent room temperature molecules. Pretend to turn up the thermostat and have the students (molecules) roleplay how they would act as they get warmer. The students should sway back and forth more and more as you pretent to turn up the thermostat higher and higher. As a result of the added movement, not as many students will be able to remain in the small space. Any students stepping outside the square must remain outside of the square. When the "molecules" are more widely spaced the density is lower. This activity illustrates that warm air is less dense than cold.
Activity #3: Have the students float a cork in a cup of water. Push the cork below the surface of the water and then let go. The cork will pop back up to the top showing that the more dense water pushed up the less dense cork.
Explanation: A hot air balloon is able to fly because the hot air in the balloon is less dense than the colder air outside the balloon. As a result, the hot air is pushed up by the surrounding cooler air. When the air inside the balloon is cooled, it becomes more dense and gravity is able to pull the balloon back to the ground. Additional explanation above.
Crazy Hot air Ballons
Using tissue paper and glue, your kids can make their own hot air ballloons. It's a great way to show that hot air rises. . Place one sheet of 20 x 30-inch (50 x 75-cm) tissue paper on top of another. Fold the pieces in half lenthwise and cut along the fold. This will make four pieces of tissue paper, each measuring 15 x 20 inchers (38 x 50 cm).
Stack the four halves evenly. Position the stack so the 20-inch (50-cm) sides are at the top and bottom. Fold the pieces in half, then fold them in half a second time in the same direciton.
Open the last fold you made and make a diagonal fold along the line. Be sure to make the fold along the margin that is not closed. Cut along the diagonal fold line.
Take one of the sheets you just made and glue it to a sheet of 20 x 30-inch (50 x 75-cm) tissue paper. (Use the glue sparingly and make the 1-inch [2.5-cm] seam along the 20-inch [50-cm] side of the sheet.) Do the same for each sheet, making four balloon sides.
Making 1-inch (2.5-cm) seams again and glue the edges of the sides together.
To make a top for the balloon, take the last sheet of 20 x 30-inch tissue paper and cut a 10 x 20-inch (25 x 50-cm) strip from one end.
Glue all four sides of the 20 x 20-inch (50 x 50-cm) square top to the sides of the balloon's larger opening.
Bend 14 inches (35 cm) of light-weight wire into a circle and twist the ends together.
Place the wire circle just inside the balloon's smaller opeing. Fold the surrounding tissue paper over the wire circle and tape in place with clear tape.
To make a heat flue for filling the balloon with hot air, cut out the ends of five cans. (Be careful of the sharp edges!) Be sure all of the diameters of the cans are the same size. (A diameter of 3 inches [7.5-cm] works well.) Remove any paper lables from the cans by soaking them in hot water. Dry the outsides of the cans, stack one on top of another, and tape them together with plenty of duct tape. (Cardboard frozen juice cans can be used instead of metal cans to make a flue.)
Caution: Before launching the balloon, reat Hot Tips. Then hold the flue over the heat source and lower the wire-ringed end of the balloon over the top end of the flue. Let the balloon fill with hot air until it will rise on its own.
HOT TIPS
Each balloon may be decorated or personalized with streamers or markers. But remind your group that any extra weight may slow the balloons down.
Find a launch site in an open area away from trees, electrical cables, and power lines. Picnic tables make good launching platforms.
Since the balloon is highly flammable, an adult should take charge of the heat source. Older students may handle the flue with thick gloves or pot holders, and younger ones can help hold the balloon in place before lift-off.
Be sure to avoid placing the flue directly in the flames.
Cool, calm days are the best for flying. Winds will quickly cool the ballons and may blow them away. And the balloons will have a har time getting started on hot, humid days
Idea by Dr. Milton Payne. Box 1307. Stepher F. Austin State University. Nacogdoches, TX 75932. Instruction reprinted with permission.
