Types of Forces
Lesson 2 of 8
Objective: SWBAT distinguish between different types of forces.
5e Lesson Plan Model
Many of my science lessons are based upon and taught using the 5E lesson plan model: Engage, Explore, Explain, Elaborate, and Evaluate. This lesson plan model allows me to incorporate a variety of learning opportunities and strategies for students. With multiple learning experiences, students can gain new ideas, demonstrate thinking, draw conclusions, develop critical thinking skills, and interact with peers through discussions and hands-on activities. With each stage in this lesson model, I select strategies that will serve students best for the concepts and content being delivered to them. These strategies were selected for this lesson to facilitate peer discussions, participation in a group activity, reflective learning practices, and accountability for learning.
The Forces and Motions unit focuses on the gravity exerted by Earth on objects at rest or in motion. With this in mind, students will investigate types of forces and the effects gravity has on moving objects. They learn how forces can stop an object from moving, increase or decrease the speed of an object moving, change its direction, and put a resting object into motion. Through models, investigations, research, and the engineering and design process, students learn that gravity is a constant force that impacts an object’s motion. The unit wraps up with students using the engineering and design process to create a zip line to illustrate the effects of gravitational force.
In this lesson, Types of Forces, I start off asking students to redefine force from our last lesson. Then I ask them write their own examples of things in life that require force. From there, I further explain that forces can be defined as balanced or unbalanced. We look at images and examples together to understand these two terms. Then, students take part in an interactive reading assignment. As they read, they identify types of forces mentioned in the articles and define them on a handout. This serves as a reference sheet for them throughout the remaining lesson and unit. After reading and getting a sense of types of forces, students are directed to stations where they take part in mini-investigations to experience these kinds of forces. We reconvene as a class for a guided discussion of our experiences at the various stations. I wrap the lesson up with an exit ticket where students analyze different pictures from the real world. They identify and label the types of forces being displayed in the image. I collect these and use them as a formative assessment.
Next Generation Science Standards
This lesson will address and support future lessons on the following NGSS Standard(s):
5-PS2-1. Support an argument that the gravitational force exerted by Earth on objects is directed down.
Students are engaged in the following scientific and engineering practices:
3.) Planning and Carrying Out Investigations- Students take part in six stations to investigate forces: gravity, friction, air resistance, magnetism, force applied, and unbalanced and balanced forces. They make observations and measurements at each station to provide evidence of a particular force and to show their understanding of each one.
The Force and Newton's Laws of Motion lesson will correlate to other interdisciplinary areas. These Crosscutting Concepts include:
2.) Cause and Effect- Students participate in stations to identify and test different forces and their effects on objects at rest and in motion.
Disciplinary Core Ideas within this lesson include:
PS2.A - Forces and Motion
PS2.B- Types of Interactions
Classroom Management Methods
Importance of Modeling to Develop Student
Responsibility, Accountability, and Independence
Depending upon the time of year, this lesson is taught, teachers should consider modeling how groups should work together; establish group norms for activities, class discussions, and partner talks. In addition, it is important to model think aloud strategies. This sets up students to be more expressive and develop thinking skills during an activity. The first half of the year, I model what group work and/or talks “look like and sound like.” I intervene the moment students are off task with reminders and redirection. By the second and last half of the year, I am able to ask students, “Who can give of three reminders for group activities to be successful?” Who can tell us two reminders for partner talks?” Students take responsibility for becoming successful learners. Again before teaching this lesson, consider the time of year, it may be necessary to do a lot of front loading to get students to eventually become more independent and transition through the lessons in a timely manner.
- EXPLORE TEAMS (Pre-Set)
For time management purposes, I use “lab rats ” where each student has a number on the back of his or her chair, 1,2,3,4 (students sit in groups of 4)and displayed on the board. For each activity I use lab rats, I switch up the roles randomly so students are experiencing different task responsibilities which include: Director, Materials Manager, Reporter, and Technician. It makes for smooth transitions and efficiency for set up, work, and clean-up.
To start I pose the question: "Who can recall the definition of force from our last lesson?" I am looking for students to apply what they learned from yesterday and connect it to today's lesson on types of forces. After a student shares, I post the definition on the board:
Force: a push or pull that acts on an object
Once we redefine the term, I explain: "Anything and everything we do requires a force." I give them a couple of examples, like "eating, and shopping" to get them to start making connections to their own lives. Then, using think, pair, share, I have students create a t-chart in their interactive notebook. On the left side, they think and write their own examples of things in life that require force. Next, students pair up with their elbow partner and together they share their lists. Finally, each pair reconvenes with their regular group. Here they share their list of things that require a force.
After generating a list, I have students work together in their groups to complete the right side of the t-chart. In this section, students list either push or pull next to the example written in the right column. I share that forces are all around us, all the time and come in many different forms. Things hanging, still or at rest, balancing, moving, spinning, sliding, etc. are all using some kind of force. All of these forces make an object change its position, direction or speed.
Then I add on and explain: "Not all forces are the same, there are actually two ways of forces working on an object, they are balanced force and unbalanced force (I have them create a chart, similar to this one, in their interactive notebook with key terms and define them as I display them on the board)
FORCE: a push or pull that acts on an object
Two Kinds of Forces
On the board, I write
- balanced force- A force that doesn't cause a change in motion to an object. That is because there are two equal forces either pushing or pulling in the opposite direction on the object.
- unbalanced force- when one force is larger than the other, the forces are not equal. This difference causes an object to change its motion, speed, and/or direction.
Reading about Forces
Once we have a general idea of how force is all around us, I hand out Kids Discover: Forces and Motion reading packet (this is a free download at Kids Discover)and interactive concept graphic organizer. This organizer is to help students keep track of the type of forces they read about. I explain to all the students, "our purpose of reading is to find out what kinds of forces cause things to move, stand still, move quickly or slowly, or change direction." As we read about forces, I add on, "You can mark up the text and highlight ideas,, and/or underlie key details.
Here I differentiate a bit by having some students who can read on their own, while I take a group (struggling readers and English language learners) to read with me. At different points while I am reading with my group, I give them a task like highlighting main ideas or finding certain words in the text. I also have them read a paragraph on their own with a question given to them like, "What does friction do to an object?" This type of close reading is beneficial for them to develop some reading skills and allows me to check in with some students reading on their own so I can make sure they are on task, understanding what they are reading, and grasping the main ideas of types of forces.
To help students synthesize what they have read, I show a quick video that gives them a snapshot of types of forces. This helps them see the forces in action while listening to the explanation.
At the end of the video, we reconvene and review the types of forces we read about and saw in the video.
Investigating Forces and Motion
I direct student’s attention to the stations set up around the room and hand out Investigating Types of Forces task/recording packet which guides them through six different tasks related to a type of force. I explain to them that they are rotating through these stations to experience different kinds of forces. Their purpose at each station is to discover the effects of a specific force on another object or itself.
These are small investigations students take part in to help them further develop their understanding about forces and how motion is affected when types of forces like gravity, friction, acceleration, and mass act upon them. I provide them with these investigations to develop their background so they are prepared when they further investigate these forces more in depth in the remaining parts of this unit.
I go over each task briefly, giving them an overall idea of what they will be doing at each station.
STATION 1: The Force of Gravity is an Up-Hill Battle
*Investigating gravity’s effect on a moving marble.
This station has a pipe insulator (forming a ‘u’ shape and extending about 36 inches off the floor at both ends. between two chairs, about 24” apart. Students release a marble from different starting points (24”, 18”, 12” and 6”), to determine the effect of gravity on a moving object. By the end of this investigation they should be able to explain why the ball cannot travel up as far on the opposite side from where it was released.
The station shows students that the marble continues to move in the direction is starts in until the effect of gravity becomes stronger than the motion of the marble and the marble cannot climb up the other side of the pipe. Gravity pulls the marble toward the ground.
STATION 2: Friction Frenzy
*Investigating the effects some materials have on an object.
This station has four boards made of different materials: sandpaper, wax paper, bubble wrap and carpet. Here students are observing how a matchbox car moves along each of these surfaces to investigate the effects of friction. Each board rests on a stack of books, creating a ramp so students can see how material affects the moving car. By the end of this investigation, students should be able to determine which surface made a difference in the way the car traveled.
This station shows students how certain materials can cause an object to move faster or slower while on it. They should be able to relate this to why they put sand on the road during a snowstorm.
STATION 3: Helicopters
*Investigating the effects of gravity and air resistance on an object in flight.
There are two pre-made paper helicopters at this station, one with short and wide blades, the other with long and narrow blades. Students release each helicopter (one at a time) from an elevated area (They use the stairwell in the hall) three different times. They are observing the effects that air resistance and gravity has on the helicopter by using a stop watch to record how long it takes for it to fall to the ground.
This station illustrates the forces of gravity and air resistance on the helicopter. Gravity is pulling the helicopter down towards the ground while the force of air is acting upward on the helicopter causing it to descend slowly.
STATION 4: Clingy Clips
*Investigating the effects of magnetism on certain materials.
At this station, students observe the effects of magnetism by trying to lift paper clips through three different cups. Each cup is a different kind of plastic. I have them try it out with different kinds of cups to illustrate the force of magnetism.
While at this station, students will notice the strength of a magnetic force as it lifts paper clips through each cup. Even though the magnet does not actually touch the paper clips, its force is strong enough to pass through cups to attract the clips.
STATION 5: A Balancing Act
*Investigating the effects of balanced and unbalanced forces.
Since it is difficult to see forces in action on large items like a building or standing wall, this station helps students visualize how these forces are working. Here a student gently pushes a chair across the floor. They are able to do this because an unbalanced force is in effect. There no force on the other side of the chair counteracting the force. Then with a partner opposite side of the chair, they both push on the chair. They should notice the chair does not move. This is because the force is balanced.
This station demonstrates the the effects of balanced and unbalanced forces. It shows students how objects move if one force is stronger than the other.
STATION 6: Applied Force
*Investigating how you can put an object in motion by applying different strengths of pulling and pushing.
During this station, students use pre-made mini-air cannons to launch a pom-pom through the air. They take turns applying different amounts of forces as they pull and release the balloon. They should recognize that the greater the force applied, the greater the distance the pom-pom travels.
This station shows students that pulling the balloon back just a little bit creates a small amount of force, but pulling the balloon back a lot, creates a bigger force, resulting in a faster pom-pom travelling at a greater distance.
I move between stations during this time, checking in on their tasks and asking them questions about what they are learning and understanding.
Once all groups have finished their investigations, we reconvene for a brief discussion on each one. We discuss the different effects they observed at each station and what they learned from it. Overall, they should recognize that an object's motion is impacted by the force of gravity, friction, air resistance, magnetism, and balanced and unbalanced forces. Discussing these concepts together helps students further develop their understanding by listening to other students share their experiences and observations and my explanations.
Apply What We Learned to the Real World
Once we finish our discussion, I hand out an exit assignment for students to complete before leaving class. This assignment has a variety of pictures from the real world on it. Their task is label each arrow with the correct type of force the image is displaying.
I collect this and use it as a formative assessment from today's lesson.