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Gravity and Friction (Chapter 2 Lesson 1)

Gravity and Friction (Chapter 2 Lesson 1)

Author: Jason Fritz

Learning Targets:
• What are some contact forces and some noncontact forces?

• What is the law of universal gravitation?

• How does friction affect the motion of two objects sliding past each other?

MN State Standards: Recognize that when the forces acting on an object are balanced, the object remains at rest or continues to move at a constant speed in a straight line, and that unbalanced forces cause a change in the speed or direction of the motion of an object. Identify the forces acting on an object and describe how the sum of the forces affects the motion of the object. Recognize that some forces between objects act when the objects are in direct contact and others, such as magnetic, electrical and gravitational forces can act from a distance. Distinguish between mass and weight.

Forces can be either contact, such as a karate chop, or noncontact, such as gravity. Each type is described by its strength and direction.

Gravity is an attractive force that acts between any two objects that have mass. The attraction is stronger for objects with greater mass.

Friction can reduce the speed of objects sliding past each other. Air resistance is a type of fluid friction that slows the speed of a falling object.


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Chapter 2 Lesson 1: Gravity and Friction Video Tutorial

Pause and rewind video to get key vocabulary concepts.

Source: adapted from McGraw-Hill; Physical iScience

Chapter 2 Lesson 1: Gravity and Friction Cornell Notes Outline

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Chapter 2 Lesson 1: Gravity and Friction

Source: McGraw-Hill; Physical iScience

Gravity and Friction Flash Cards

Source: created with Quizlet

Newtonian Gravity: Crash Course Physics #8

I'm sure you've all heard about Isaac Newton and that apple that fell on his head and how that was a huge deal to our understanding of gravity. Well... let's talk about that. In this episode of Crash Course Physics, Shini sits down to talk about the realities of the apple story and how Newtonian Gravity is more than a little important.


Source: McGraw/Hill; Physical iScience

Gravitation: The Four Fundamental Forces of Physics #3

Hank continues our series on the four fundamental forces of physics with a description of gravitation -
the interaction by which physical bodies attract with a force proportional to that of their masses, and which is responsible for keeping planets in orbit, among other things.

Source: SciShow

Gravity Compilation: Crash Course Kids

Maybe you'd like to just hear about one topic for a while. We understand. So today, let's just watch some videos about Gravity. We'll learn about why we don't fly off into space, what mass has to do with it, how does air resistance work, and why gravity is different on the moon. In this compilation, Sabrina helps us understand some of these things.

Introduction to Gravity

Basics of gravity and the Law of Universal Gravitation

Source: Khan Academy

Reading Coach - Chapter 2 Lesson 1: Gravity and Friction

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Source: McGraw-Hill; Physical iScience

Chapter 2 Lesson 1: Gravity and Friction Assignment

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Source: McGraw-Hill; Physical iScience

Gravity Force Lab

Visualize the gravitational force that two objects exert on each other. Adjust properties of the objects to see how changing the properties affects the gravitational attraction.
Relate gravitational force to masses of objects and distance between objects.
Design experiments that allow you to derive an equation that relates mass, distance, and gravitational force.
Use measurements to determine the universal gravitational constant.

Source: PhET University of Colorado

Gravity Exploration

Part A:
How much would you weigh on other planets and the moon? The more mass a planet has, the more gravity it has. Planets which have more mass than Earth would have more gravity than Earth. A person would weigh more on these planets than they do on Earth Gravity Exploration

Part B: How far could you jump on other planets and the moon? Determine how far you can jump on the Earth. To do this, place a piece of tape on the floor as a starting line. Jump as far as you can off of both feet. Have your partner mark where you land not where you end up! Measure the distance and record in the table. Do this five times, then find the average.

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Science Court: Gravity

Forces Comic Strip

Forces Comic Poster Rubric

1. 9 different types of forces are used in the comic strip (3 non-contact, 6 contact).
___/5 pts

2. The top has a clever title with student's name
___/1 pts

3. Each box is neatly designed with color.
___/5 pts

4. Each picture accurately depicts the force it’s demonstrating with a description and is titled.
___/4 pts

Total Points for Assignment:
___/15 pts

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What is Friction?

Friction is a very important concept of physics.In this animated educational video, kids can learn about the meaning of friction.When and where effects of friction can be felt? And what are the advantages and benefits of friction.

Static and Kinetic Friction Example

Thinking about the coefficients of static and kinetic friction

Source: Khan Academy

What is Friction?

Friction keeps us from slipping and falling everywhere. It is the resistance formed between 2 surfaces in contact.

Have you seen someone slip and fall off a chair? Did it make you laugh? Imagine if we were constantly slipping of chairs and beds and stairs… life wouldn’t be very fun, would it?

Thanks to friction this does not happen. Everything would just keep slipping and falling all over the place if it wasn’t for friction. Friction is a force that is created when two surfaces move or try to move across each other. The amount of friction produced during this process depends on the texture of both the surfaces and the amount of contact force pushing the two surfaces together.

Friction always opposes the motion or attempted motion of one surface across another surface. As the two surfaces slide against each other, their contact is anything but smooth. They both grind and drag against each other, producing friction. You will find friction everywhere that objects come into contact with each other.

The force acts in the opposite direction to the way an object wants to slide. When you want to stop your bicycle, you press the brake and your bicycle slows down because of the friction between the brakes and the wheels. If you are running on a playground and hear your friend call you and suddenly want to stop, you can, because of the friction between your shoes and the ground.

Source: Mocomi Kids

Friction: Crash Course Physics #6

Why is it hard to move a heavy bookcase across a carpeted floor? And why is it easier to keep it moving than it was to get it started moving? You might think it's all about weight, but actually it's about friction. Two kinds of friction! In today's episode of Crash Course Physics, Shini Somara tells us about Static and Kinetic friction; how they work and how they're different.

Friction Lab Sheet

Friction is a force that occurs when two surfaces TOUCH. In this lab you will investigate the factors that affect friction. You will measure frictional forces using a spring scale to measure the force. The factors being tested will include the effect of surface texture, weight and surface area contact on friction. In addition you will investigate the difference between ““Static”” and ““Sliding”” friction.

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What If The Sun Disappeared?

Source: Vsauce

How Much Does Thor's Hammer Weigh?

Source: Vsauce

Galileo Drops the Ball

In around 1590 Galileo Galilei (1564-1642) climbed up the Leaning Tower of Pisa and dropped some balls to the ground. Two balls of different masses, but of similar shape and density that were released together hit the ground at the same time. Until then it was commonly believed that heavy things fall faster than light things. Many people still believe this, and casual observation of everyday phenomena often does tend to confirm this view.

If you drop a brick and a feather at the same time the brick will probably hit the ground first. But this is because of differences in the amount of friction between these objects and the air around them, not because their masses are different. If there were no air, the feather and the brick would hit the ground at the same time.

Galileo’s discovery is important in understanding how parachutes work. They fall slowly through the air because of friction.

Click on image to explore

Source: Schlumberger Excellence in Education Development

Gravity Force Lab

*click on image to go to virtual lab

Learning Goals

Relate gravitational force to masses of objects and distance between objects.
Explain Newton's third law for gravitational forces.
Design experiments that allow you to derive an equation that relates mass, distance, and gravitational force.
Use measurements to determine the universal gravitational constant.

Source: phET Interactive Solutions

What is Force in Physics? by Professor Mac

Force. What is force in physics? Force is a concept used in physics. Newton's laws of motion use force to explain the motion of objects. In this video Professor Mac explains the concept of force through a series of exciting experiments.

Source: learnwithmac

Safari Montage Videos

To sign on to Safari Montage use the same user-name and password as you would to sign onto the school computers.

Real World Science: Forces

Featuring peer hosts and colorful graphics, this educational, live-action program explores the impact forces have on everyday life. The program covers the properties of forces, Newton's Laws of Motion, push and pull, friction, balanced and unbalanced forces, gravity, electromagnetism and pressure.

18 min 13 sec.

The Science of Disney Imagineering: Gravity

Join Walt Disney Imagineer Asa Kalama on a ride into the world of imagination, inspiration and science -- the science of gravity. Explore the Disney theme parks and learn how Disney Imagineers put gravity to work as they design and build amazing attractions like the Matterhorn, Rock 'n' Roller Coaster, Mission: SPACE and Twilight Zone Tower of Terror.

25 min 56 sec

Design Squad: Gravity Bikes

Watch the Design Squad teams in a head-to-head competition as they build high-speed gravity bikes for Gravity Sports International champion Tom Whalen. ''Design Squad'' is an award-winning reality competition series whose goal is to increase students' knowledge of engineering, the design process, and the roles of engineering and design in society.

26 min 29 sec.

Bill Nye: Gravity

Bill Nye the Science Guy explores the topic of gravity in this episode of The Disney Channel series, featuring an interactive question-and-answer format and hands-on activities. In this episode, Bill looks at how gravity holds the ocean on Earth, makes Earth round and keeps humans on the ground. Designed to correlate with National Science Standards, the program includes a teacher's guide filled with suggestions for extension activities and classroom experiments.

23 min 2 sec.

The Science of Disney Imagineering: Friction

Join Walt Disney Imagineer Asa Kalama on a ride into the world of imagination, inspiration and science -- the science of friction. Explore the Disney theme parks and learn how Disney Imagineers put friction to work as they design and build amazing attractions like Slush Gusher, the Richard Petty Driving Experience and Lights, Motors, Action! Extreme Stunt Show.

27 min 44 sec


In Friction, two young islanders, Olive and Troy, are delivering mail with a mammoth-drawn wagon when they learn how important the force of friction is as they attempt to slow down! Applying what they discover about friction, Olive and Troy test a variety of brakes, trying to find the type just right for them. Even with proper brakes, it does take some time to come to a stop, though. Young Troy and Olive find this out as they join their two delivery mammoths for an unscheduled bath after a foiled attempt to stop quickly! Part of the multivolume series The Way Things Work, based on the best-selling book by David Macaulay.

13 min 32 sec


Most people think friction is what happens when two things are rubbed together. But there's so much more! Friction is a force that resists motion. Yet, without friction, motion would be impossible. Students will learn more about this natural force and the attempts made at controlling it in the world. Includes a hands-on activity and graphic demonstrations. 

22 min 22 sec.

Bill Nye: Friction

Bill Nye the Science Guy illustrates how various types of transportation utilize friction, from the use of traction in trains and the ''roll'' of ball bearings in skateboards and automobiles, to the lack of friction in a hovercraft. This live-action, fast-paced program also features comedy, music videos, interviews with real scientists and hands-on experiments to make the concepts presented understandable and fun.

23 min 4 sec

Sir Isaac Newton: The Gravity of Genius

A&E examines the life and remarkable genius of Sir Isaac Newton, the ''Father of Modern Science.'' Using interviews with leading scientists, the program examines Newton's many discoveries and traces their impact, from the foundations of calculus and the laws of gravity, motion and inertia to his major work, ''Principia Mathematica.'' The program traces the vibrant social life and times of one of history's greatest minds, while also exploring his private struggles with loneliness and self-doubt. 

45 min 52 sec.

Other Video Links:

The Universe: Gravity

A look at the forces of gravity and the role it plays in the formation of the universe and the objects within it; how weightlessness affects astronauts in space, and how pilots experience the effects of gravity in their training on the "vomit comet". (History Channel)

44 min 37 sec.

Big History: Defeating Gravity

With the right kind of air, the perfect materials and cosmic forces that are just right for us to leave the ground without tumbling off into space, Big History reveals how Earth is the perfect planet for flight. (History Channel)

21 min 35 sec.

Newton's Explanation of Gravity

On Discovery's Assignment Discovery, Newton was the first to understand that gravity was a universal force that influenced all objects even in space. (Discovery)

2 min 4 sec.

Rosetta's 10-Year Gravity Fling to Catch a Comet

As gobsmackingly cool as it is to land on a comet AT ALL, the Rosetta craft's journey just to catch up to the flying rock was mind boggling in its own right. Trace explains the dizzying physics and helpful assist from gravity that made it possible. (Discovery News)

4 min 26 sec.

Source: Safari Montage