Post on 31-Jan-2018
transcript
© 2011 Watsonville Environmental Science Workshop. All Rights Reserved worldwide. When linking to or using WESW content, images, or videos, credit MUST be included.
Propeller-‐Powered Car
Category: Physics: Electricity & Magnetism; Force & Motion
Type: Make & Take Rough Parts List:
How To:
Drill 4 holes into the craft stick.
Loop a paperclip around 1 of the brass tacks.
1 Craft Stick 4 Car wheels 2 Straws 2 Skewer sticks 1 Motor 1 Card stock or playing card for
propeller 1 Piece of hot glue stick, ¼” long 1 Material for propeller platform 1 Electrical wire 2 Brass tacks 1 Paper clip 1 9V battery 1 9V battery snaps 1 Plastic bottle, optional 1 Bamboo skewer, optional 1 Small piece of paper, optional Scissors Rubber bands Hot glue gun
© 2011 Watsonville Environmental Science Workshop. All Rights Reserved worldwide. When linking to or using WESW content, images, or videos, credit MUST be included.
Insert brass tacks into the 2 center holes in the craft stick. This is called the “stitch”.
Use a rubber band to attach a 9V batter snap to the craft stick.
Connect 1 battery wire to a brass tack. Cut a propeller.
Make a propeller from a piece of plastic or cardstock glued to a piece of hot glue.
Attached the electrical wires to the motor. Solder is shown here, but you can
just twist them on too.
© 2011 Watsonville Environmental Science Workshop. All Rights Reserved worldwide. When linking to or using WESW content, images, or videos, credit MUST be included.
Build a platform and put the propeller on it. Connect one electrical wire from the motor to the bottom of the brass
tack that is not connected to the battery. Connect the loose battery wire to
the loose electrical wire on the motor.
Insert a skewer into each straw. Attach wheels onto
the ends of each skewer.
© 2011 Watsonville Environmental Science Workshop. All Rights Reserved worldwide. When linking to or using WESW content, images, or videos, credit MUST be included.
Glue the straws onto the bottom of the car. Swing the paperclip around
to connect the 2 brass tacks and send electricity to the motor.
To decorate your car, cut the center ring of a plastic bottle
and wrap it around the propeller.
Cut the paper into the shape of a flag and attach it onto the bamboo skewer
to make a flag.
Fine Points: → The materials used to build this car should be very lightweight. → The 2 center holes in the craft stick should be drilled about a paperclip’s distance apart so that the
paperclip can close the circuit for battery power. → The key to making the car move is to have as little friction as possible. The vehicle should be
designed to minimize friction between the car, its wheels, and the ground. → This car will move much easier on a smooth surface.
Concepts Involved: • Forces • Friction • Newton’s Laws of Motion:
− An object at rest will remain at rest unless acted on by an unbalanced force. An object in motion continues in motion with the same speed and in the same direction unless acted upon by an unbalanced force.
© 2011 Watsonville Environmental Science Workshop. All Rights Reserved worldwide. When linking to or using WESW content, images, or videos, credit MUST be included.
− Acceleration is produced when a force acts on a mass. The greater the mass of the object being accelerated the greater the amount of force needed to accelerate the object.
− For every action, there is an equal and opposite reaction.
Elaboration: Without an engine, this car relies entirely upon a propeller to move it around. Newton’s Laws of Motion help us to understand how propeller-‐based cars move. Newton’s 1st Law says that an object at rest will remain at rest unless acted on by an unbalanced force. When sitting on flat ground, the propeller-‐based car needs the force from a propeller to move it around. After the propeller has been turned on and the car has started moving, it will keep moving until it hits a wall or hits some high higher friction. The car’s speed is influenced by the amount of friction created between its wheels and the ground. If the car is moving on a rough, bumpy surface or if its wheels are uneven, friction will slow down the car. If the car is moving on a smooth surface and its wheels are even and smooth, the car will move faster. This propeller-‐based car moves quickly because it is made of lightweight material. If it were made of heavier wood or metal, a more power would be needed to accelerate the car at the same rate as the lightweight model. Newton’s 2nd law explains that the greater the mass of the object being accelerated, the greater the amount of force needed to accelerate the object. Newton’s 3rd Law tells us that for every action, there is an equal and opposite reaction. The propeller of the car has been set up so that when it moves, it throws air behind the car. The action of the propeller creates an equal and opposite reaction pushing the car forward.
Links to k-‐8 California State Standards: Grades k-‐8 Standard Set Investigation and Experimentation Scientific progress is made by asking meaningful questions and conducting careful investigations. As a basis for understanding this concept and addressing the content in the other strands, students should develop their own questions and perform investigations. Grades k-‐12 Mathematical Reasoning: 1.0 Students make decisions about how to approach problems: 1.1 Analyze problems by identifying relationships, distinguishing relevant from irrelevant information,
sequencing and prioritizing information, and observing patterns. 1.2 Determine when and how to break a problem into simpler parts. 2.0 Students use strategies, skills, and concepts in finding solutions: 2.1 Use estimation to verify the reasonableness of calculated results. 2.2 Apply strategies and results from simpler problems to more complex problems. 2.3 Use a variety of methods, such as words, numbers, symbols, charts, graphs, tables, diagrams, and
models, to explain mathematical reasoning. 2.5 Indicate the relative advantages of exact and approximate solutions to problems and give answers to
a specified degree of accuracy. 3.0 Students move beyond a particular problem by generalizing to other situations: 3.1 Evaluate the reasonableness of the solution in the context of the original situation. 3.2 Note the method of deriving the solution and demonstrate a conceptual understanding of the
© 2011 Watsonville Environmental Science Workshop. All Rights Reserved worldwide. When linking to or using WESW content, images, or videos, credit MUST be included.
derivation by solving similar problems. 3.3 Develop generalizations of the results obtained and apply them in other circumstances. Grade 2 Standard Set 1. Physical Sciences The motion of objects can be observed and measured. 1.a. Students know the position of an object can be described by locating it in relation to another object or to the background. 1.b Students know machines and living things convert stored energy to motion and heat. 1.c. Students know the way to change how something is moving is by giving it a push or pull. The size of the change is related to the strength, or the amount of force, of the push or pull. Grade 3 Standard Set 1: Physical Sciences (Energy and Matter) Energy and matter have multiple forms and can be changed from one form to another. 1.b Students know sources of stored energy take many forms, such as food, fuel, and batteries. 1.c. Students know machines and living things convert stored energy to motion and heat. 1.d. Students know energy can be carried from one place to another by waves, such as water waves and sound waves, by electric current, and by moving objects. Grade 4 Standard Set 1: Physical Sciences Electricity and magnetism are related effects that have many useful applications in everyday life. 1.a. Students know how to design and build simple series and parallel circuits by using components such as wires, batteries, and bulbs. 1.g Students know electrical energy can be converted to heat, light, and motion. Grade 8 Physical Standards Standard Set 2. Forces: Unbalanced forces cause changes in velocity. 2.a. Students know a force has both direction and magnitude. 2.c. Students know when the forces on an object are balanced, the motion of the object does not change. 2.d. Students know how to identify separately the two or more forces that are acting on a single static object, including gravity, elastic forces due to tension or compression in matter, and friction. 2.f. Students know the greater the mass of an object, the more force is needed to achieve the same rate of change in motion. Grade 9-‐12 Physics Standard Set 1. Motion & Forces Newton’s laws predict the motion of most objects. 1.d Students know that when one object exerts a force on a second object, the second object always exerts
a force of equal magnitude and in the opposite direction (Newton’s Third Law) 1.f Students know applying a force to an object perpendicular to the direction of its motion causes the
object to change direction but not speed.