science project for class 6th
Answers
Answer:
Introduction
Balloon-powered cars, like the ones in Figure 1, are fun to build and even more fun to play with. In this project you will be challenged to build and test your own balloon-powered car. A balloon-powered car consists of three main parts:
The body of the car (piece of cardboard or plastic bottle in Figure 1)
The wheels of the car (CDs or plastic bottle caps in Figure 1)
The axles, which connect the wheels to the body, and allow the wheels to spin (wooden skewers in Figure 1)
Continue reading to learn more about the physics of how a balloon-powered car works.Have you ever blown up a balloon and then let it go, without tying it shut? The air rapidly escapes from the balloon, making it zip all over the room! This is because when you blow up a balloon, you increase the air pressure inside the balloon. This air pressure stretches out the rubber balloon material, just like stretching a rubber band. Both the air pressure and the stretched rubber store potential energy, or energy that is "waiting" to do something. See Figure 2.
A deflated blue balloon An inflated blue balloon
Figure 2. (Left) An un-inflated balloon does not store any potential energy. (Right) An inflated balloon stores potential energy in the forms of air pressure and stretched rubber.
When you let the balloon go, the rubber contracts, and air is rapidly squeezed out the opening of the balloon. The potential energy inside the balloon is converted to kinetic energy, or energy of motion, of the fast-moving air through the opening. Because the air is pushed out rapidly backwards, there is a reaction force that pushes the balloon forward, as shown in Figure 3. This principle comes from Newton's third law of motion, which states "for every action, there is an equal and opposite reaction."
Drawing of an inflated balloon being pushed forward while air is pushed out the back of the balloon
Figure 3. According to Newton's third law of motion, when air is pushed backwards out of the balloon (out the end with the opening), there must be an equal and opposite reaction force that pushes the balloon forward (the end opposite the opening).
When you just let a balloon go on its own, it tends to randomly fly around the room, and is almost impossible to steer. However, when you attach the balloon to a car, like the ones shown in Figure 1, you can harness the balloon's energy to propel the car forward! The engineering goal in this project will be to design, build, and test a car that is powered by nothing but a balloon. You want to design your car so it can travel as far as possible. For the ultimate test, you can follow a strict set of design rules used in the Fluor Engineering Challenge (see the Procedure for details).
Terms and Concepts
Body (of a car)
Wheel
Axle
Air pressure
Potential energy
Kinetic energy
Reaction force
Newton's third law of motion
Design requirements
Iteration
Questions
What is potential energy?
What are some different ways potential energy can be stored?
What is kinetic energy?
What is Newton's third law of motion?
What are some common materials and designs used to build balloon cars?
Bibliography
Rader, A. (n.d.). Energy Around Us. Physics4Kids. Retrieved December 15, 2014.
Rader, A. (n.d.). Newton's Laws of Motion. Physics4Kids. Retrieved December 15, 2014.
Materials and Equipment
If you want to challenge yourself and compare your car's performance to other students' cars, you can follow the guidelines in the Fluor Engineering Challenge where you can only use the materials listed here. The maximum allowable quantity for each item is listed in parenthesis.
CDs (4)
Answer:
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Explanation: