Students will understand the following:

Distribute the following materials to each group of students:


Adaptations for Older Students: Ask students to identify which of Newton's laws their experiment illustrates. Challenge them to determine a mathematical relationship between the mass of the car and the weight of the object attached to the paperclip hook. 

You can evaluate your students on their diagrams and experiments using the following threepoint rubric:

Acceleration vs. Constant Speed Ask your students to make a list of five different moving objects they have observed in the past 24 hours. For each item on their list, they should identify the forces and counterforces that were acting on it, and then determine whether the object was experiencing constant speed or acceleration. (Acceleration is positive when the forces acting on an object are stronger than the counterforces and negative when the reverse is the case. Negative acceleration can be thought of as deceleration.) Using words such as force , counterforce , balanced , and unbalanced , students should explain why some of the objects they observed were moving with constant speed while others were accelerating. Air Resistance and Acceleration Ask your students to use a stopwatch to measure the time it takes a freely rolling toy car to roll from the top to the bottom of a slightly inclined board. Instruct them to record their times. Ask students if the car appears to be rolling with a constant speed or accelerating. Then have students cut three squares out of a stiff piece of cardboard, making one square 5" x 5", one 10" x 10", and one 20" x 20". Have them fasten the 10" x 10" square onto the front of the toy car so that the plane of the square is perpendicular to the forward motion of the car. Next, have students measure and record the time it takes their "sail car" to roll from the top to the bottom of the same inclined board. Instruct students to make a diagram of each part of the experiment, representing each force and counterforce acting on the car with a labeled arrow indicating the force's probable direction. Students should use their diagrams to explain the difference they observed in the times they recorded, both with and without the "sail." Students can then use similar diagrams to predict what will happen when they replace the first cardboard "sail" with the other two and conduct experiments that will test their hypotheses. 
Fatal Forces Nick Arnold. Scholastic, 1997. Let science be fun as this college professor explains physical forces so that even nonscientists can understand them. Lots of humor and lots of cartoons make this an entertaining, informative volume. Movement Sally and Adrian Morgan. Facts on File, 1993. Animals have adapted over many thousands of years to move successfully; man has studied and put to use the design of animals to make machines that move. The experiments provided in this book allow a better understanding of both animals and machines and the forces that affect their movement. An index, glossary, and answers to questions are included. 
Experiments and Demonstrations with Air Pressure Hands on activities that use Bernoulli's Principle to lift heavey weights, syphon water, crack boards, crush soda cans and much more. Principles of Aeronautics At a beginner, intermediate or advanced level, learn how aeronautical principles are applied to the study of the atmosphere and weather, vehicles, sports equipment, animals, and even mythological characters. Is Air Something? Fifteen lessons about air pressure with hands on activities that involve parachutes, bubbles, paper airplanes, balloons, whirling wonders, wind vanes and more. Aeronautics Learning Laboratory for Science Technology and Research An online Aeronautical tutorial includes multimedia presentations on the history and principles of flight on three different levels of difficulty. FoilSim Virtual Wind Tunnel In this interactive virtual wind tunnel students analyze the effects on the motion of an airplane wing or baseball by changing their position and shape, by moving slider controls that vary the parameters of airspeed, altitude, angle of attack, thickness and curvature. 
Click on any of the vocabulary words below to hear them pronounced and used in a sentence.
Context: If the forces acting on an object do not cancel each other out, the object might change speed and accelerate.
Context: An object is said to be in balance when all of the forces and counterforces acting on it cancel each other out.
Context: Air resistance provides a counterforce to gravity as a skydiver falls out of an airplane.
Context: Gravity is one of the fundamental forces that acts on an object in flight. 
This lesson plan may be used to address the academic standards listed below. These standards are drawn from Content Knowledge: A Compendium of Standards and Benchmarks for K12 Education: 2nd Edition and have been provided courtesy of theMidcontinent Research for Education and Learningin Aurora, Colorado. Grade level: 68, 912 Subject area: science Standard: Understands motion and the principles that explain it. Benchmarks: Benchmark 68: Understands effects of balanced and unbalanced forces on an object's motion (e.g., if more than one force acts on an object along a straight line, then the forces will reinforce or cancel one another, depending on their direction and magnitude; unbalanced forces such as friction will cause changes in the speed or direction of an object's motion). Benchmark 912: Knows that laws of motion can be used to determine the effects of forces on the motion of objects (e.g., objects change their motion only when a net force is applied; whenever one object exerts force on another, a force equal in magnitude and opposite in direction is exerted on the first object; the magnitude of the change in motion can be calculated using the relationship F = ma, which is independent of the nature of the force). Grade level: 912 Subject area: mathematics Standard: Understands and applies basic and advanced properties of the concepts of geometry. Benchmarks: Benchmark: Understands the characteristics and uses of vectors (e.g., representations of velocity and force). Benchmark: Uses geometric constructions (e.g., the parallel to a line through a given point not on the line, line segment congruent to a given line segment) to complete simple proofs, to model, and to solve mathematical and realworld problems. 
Ted Latham, physics and science/technology teacher, Watchung Hills Regional High School, Warren, New Jersey. 
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