In the first of two lessons of this curricular unit, students are introduced to the concept of friction as a force that impedes motion when two surfaces are in contact. Student teams use spring scales to drag objects, such as a ceramic coffee cup, along a table top or the floor, measuring the frictional force that exists between the moving object and the surface it slides on. By modifying the bottom surface of the object, students find out what kinds of surfaces generate more or less friction. They also discover that both static and kinetic friction are involved when an object initially at rest is caused to slide across a surface. In the second lesson of the unit, students design and conduct experiments to determine the effects of weight and surface area on friction. They discover that weight affects normal friction (the friction that results from surface roughness), but for very smooth surfaces, the friction due to molecular attraction is affected by contact area.

Explore the forces at work when you try to push a filing cabinet. Create an applied force and see the resulting friction force and total force acting on the cabinet. Charts show the forces, position, velocity, and acceleration vs. time. View a Free Body Diagram of all the forces (including gravitational and normal forces).

Explore the forces at work when you try to push a filing cabinet. Create an applied force and see the resulting friction force and total force acting on the cabinet. Charts show the forces, position, velocity, and acceleration vs. time. View a Free Body Diagram of all the forces (including gravitational and normal forces).

Explore the forces at work in a tug of war or pushing a refrigerator, crate, or person. Create an applied force and see how it makes objects move. Change friction and see how it affects the motion of objects.

Explore the forces at work when you try to push a filing cabinet. Create an applied force and see the resulting friction force and total force acting on the cabinet. Charts show the forces, position, velocity, and acceleration vs. time. View a Free Body Diagram of all the forces (including gravitational and normal forces).

Students take a closer look at cars and learn about some characteristics that affect their energy efficiency, including rolling resistance and the aerodynamics of shape and size. They come to see how vehicles are one example of a product in which engineers are making changes and improvements to gain greater efficiency and thus require less energy to operate.

This activity was designed for blind learners, but all types of learners can use it to identify increases in friction.

Learn how friction causes a material to heat up and melt. Rub two objects together and they heat up. When one reaches the melting temperature, particles break free as the material melts away.

Learn how friction causes a material to heat up and melt. Rub two objects together and they heat up. When one reaches the melting temperature, particles break free as the material melts away. Arabic Language.

Students use LEGO® MINDSTORMS® robotics to help conceptualize and understand the force of friction. Specifically, they observe how different surfaces in contact result in different frictional forces. A LEGO robot is constructed to pull a two-wheeled trailer made of LEGO parts. The robot is programmed to pull the trailer 10 feet and trial runs are conducted on smooth and textured surfaces. The speed and motor power of the robot is kept constant in all trials so students observe the effect of friction between various combinations of surfaces and trailer wheels. To apply what they learn, students act as engineers and create the most effective car by designing the most optimal tires for given surface conditions.

Using different material surfaces, students can measure the amount of friction force (Newtons) that is required to drag a mass weight or wooden block across each type of surface material. Students will collect and graph data, identifying independent and dependent variables, and complete a scaffolded conclusion.

This lesson looks at the impact friction has on motion by running toy cars on different surfaces. Students will measure the distance the toy car travels down a ramp and see how adding sandpaper as a source of friction impacts distance.

Students gain first-hand experience on how friction affects motion. They build a hovercraft using air from a balloon to levitate a craft made from a compact disc (CD), learning that a bed of air under an object significantly reduces the friction as it slides over a surface.

Students measure and analyze forces that act on vehicles pulling heavy objects while moving at a constant speed on a frictional surface. They study how the cars interact with their environments through forces, and discover which parameters in the design of the cars and environments could be altered to improve vehicles' pulling power. This LEGO® MINDSTORMS® based activity is geared towards, but not limited to, physics students.

Students are introduced to the concept of inertia and its application to a world without the force of friction acting on moving objects. When an object is in motion, friction tends to be the force that acts on this object to slow it down and eventually come to a stop. By severely limiting friction through the use of the hover pucks, students learn that the energy of one moving puck is transferred directly to another puck at rest when they collide. Students learn the concept of the conservation of energy via a "collision," and will realize that with friction, energy is converted primarily to heat to slow and stop an object in motion. In the associated activity, "The Puck Stops Here," students will investigate the frictional force of an object when different materials are placed between the object and the ground. This understanding will be used to design a new hockey puck for the National Hockey League.

Why static friction is harder to overcome than kinetic friction. Created by Sal Khan.

This activity is a field investigation where students will gather data on speed, acceleration, gravity, friction, and forces. They will design and conduct an investigation.

This activity needs large linoleum, carpet and tar or asphalt space to race student constructed balloon powered cars. Students will learn that speed, velocity, and changes in velocity are the result of the action of forces on objects

Through the use of marbles, this investigative experiment gives students the opportunity to learn about motion.