In a Senior Years class, there are no safety issues for this experiment. However, if a teacher were to rework this experiment for an elementary level class, the ping-pong ball may be considered a choking hazard.
Specific Learning Outcomes and General Learning Outcomes:
S2-4-04: Explain the formation and dynamics of selected severe weather phenomena.
S2-4-05: Collect, interpret, and analyze meteorological data related to a severe weather event. This experiment can give students an idea of how complicated weather systems can be. Even in a simple experiment such as this, the ping-pong ball is being thrown around by high and low pressure systems. Just imagine all the forces acting during a thunderstorm of hurricane.
S2-4-07: Investigate and evaluate evidence that climate change occurs naturally and can be influenced by human activities.Changing the direction or force of how hard the demonstrator blows into the cup will have a great effect on the movement of the ping-pong ball. This could give the students something to think about. How may our actions be influencing global climate patterns?
A1: Recognize both the power and limits of science as a way of answering questions about the world and explaining natural phenomena. As previously mentioned, this experiment could help students see how complicated weather systems can be. We do not yet have a total understanding of all the forces involved in severe weather.
B5: Identify and demonstrate actions that promote a sustainable environment, society, and economy, both locally and globally.
D4: Understand how stability, motion, forces and energy transfers and transformations play a role in a wide range of natural phenomenon.
E1: Describe and appreciate the similarity and diversity of forms, functions, and patterns within the natural and constructed world. There are some other examples of phenomena that act in a similar manner to what the students see in this experiment. For example, diffusion and osmosis are similar, in that both involve movement from high pressure or concentration to low pressure or concentration.
E2: Describe and appreciate how the natural and constructed world is made up of systems and how interactions take place within and among these systems.
E4: Recognize that energy, whether transmitted or transformed, is the driving force of both movement and change, and is inherent within materials and in the interactions among them.
2. Ask question: How can I get the ping-pong ball from one cup to the other without touching the ball or the cups?
3. After a short discussion (first mention that no one who knows how the ball can be moved is allowed to give away the answer) it is time to perform the experiment.
4. Blow sharply into the far side of the cup. Blow in the direction that you want the ball to jump. The harder you blow, the higher and further the ball will jump.
5. Ask students to observe how the ball moves throughout the experiment. Repeat the demonstration so that they focus on the movement of the ball.
6. Ask if anyone can tell what caused the ping-pong ball to jump from the first cup to the second cup.
7. Show how pressure builds up in the bottom of the cup in-front of the ping-pong ball (on chalkboard) and forces the ball out of the cup. Show that the low pressure outside of the cup (where you are blowing) forces the ball into a path towards the other cup. Show that the harder you blow the farther the ball goes.
8. Ask if they know any other times when this happens in their day-to-day lives. Some of the examples include weather systems, i.e. Storm fronts, and what happens when you sit on a beanbag chair. Also, students may have seen similar motions in other science classes, such as diffusion and osmosis.
Theoretical background: When you blow into the far side of the glass the pressure starts to build up along that side. The pressure build-up then forces the ping-pong ball up out of the glass. The ball doesn’t fall out of the glass on the side it was placed because the airflow above the glass is actually creating an area of low pressure. The ping-pong ball then travels along the path of the low-pressure flow in the general direction of the other glass. This low pressure area increases with the speed of the air blown into the glass, since the rate of pressure increase within the glass has increased, and the ping-pong ball can actually “jump” further, allowing us to move the second glass farther and farther away, the faster we blow.
How this event can create disequilibrium: This event can create disequilibrium for the students since they would normally expect that blowing down on an object would pin it down, instead, due to the build-up of pressure, the ping pong ball jumps into the air.
References: Manitoba Education, Training and Youth, 2001. Manitoba Curriculum Framework of Outcomes. Winnipeg, MB: Manitoba Education, Training and Youth.
Science Inquiry, n.d. The Leaping Egg. Retrieved on October 14, 2005, from http://www.scienceinquiry.com/demo1198-3.htm.