ALEX Lesson Plan

Students will determine the difference between balanced and unbalanced forces through an experiment. The experiment consists of a student-created scaled snow sled model going down a teacher-created ramp. Students will plan to change one variable, collect data, and chart the data graphically. Students will change a variable such as: number of students riding the snow sled, size of the child (children) riding the snow sled, direction, position on the hill the snow sled is released, position of children on the sled (sitting, standing, laying), friction caused by materials that makes up the sled, and air resistance caused by an object such as a parachute. Students will collect and chart data of each experiment graphically in order to determine the longest snow sled ride.

This lesson results from the ALEX Resource Gap Project.

The teacher will need: 

• Post-it notes (enough for each student to have at least 5)
• Chart Paper
• Journal for each student to record discussions, hypotheses, and collected data
• Index cards for vocabulary flashcards (10 per student)
• Optimal Snow Sled Experience Presentation Rubric (print for each student or display for the class)
• Several textbooks for ramp design
• Piece of wood for ramp design

The teacher will need to provide access to the following materials for each teacher-created group of three to four students:

• Chromebooks or portable device to research ideas such as iPad, tablet, etc. (one for each group)
• Internet access
• bucket, small plastic bin, plastic bowl, paper bowl, plastic dessert plate, paper dessert plate, frisbee, tin foil (enough for each group to construct one model assigned by the teacher, the groups should be strategically created)
• Tape (one roll for each group, having the easy dispense kind is best to manipulate the use of the tape while they are constructing)
• Paper (cardstock or any type of sturdy paper)
• String or yarn (Keep a roll at each group's disposal. The extra can be saved for later.)
• Legos (Students may bring these from home with parent permission. Return these items to students who brought them after testing the snow sled).
• Marbles (Students may bring these from home with parent permission. Return these items to students who brought them after testing the snow sled).
• Plastic spoons (One box per group. The extra can be saved for later.)
• Popsicle sticks or craft sticks (One box for each group. The extra can be saved for later.)
• Foam cups (A few for each group)
• Stopwatch (One for each group)
• Ruler (One or two for each group)
• Balance scale (One for class observation, and one for each group)

• Chart paper or Google slides (optional)

Computer or personal device (such as a tablet or iPad) with internet access to research, design, and view: Snow Sledding FAILS & Wipeout Compilation, How to make a popsicle snow sled, Top Five Snow Sleds , Homemade sled for 8 dollars.

Prior to the lesson the teacher should:

• gain access to electronic devices and the internet.
• gather all supplies listed under Materials and Resources.
• be aware of the effects of balanced and unbalanced forces--if he/she were to sit in the middle of a snow sled as opposed to leaning to one side.
• review how to read a 12" ruler with students.
• have taught how to plot given data on at least one type of graph or chart ( e.g.: bar graph, t-chart).
• be prepared to label and mark each ride of each group with tape and a marker. (The teacher may choose to designate sticky dot colors to groups and use them instead by labeling each dot with 1, 2, 3 to indicate the snow sled test number.)
• construct the ramp by:

1. Clearing a space about 10 feet long--this will be the runway.
2. Stacking two or three thick textbooks at one end of the runway.
3. Leaning one end of a wooden board on the books and place the other end on the floor.
4. Marking the top to the ramp with tape and label it "start."

Prior to the lesson, the teacher will ensure students are proficient in the following skills:

• Students should be able to plot or arrange data on a chart. 

• Students should be able to read a 12” ruler.

• Students should be able to use a stopwatch to time each “ride” of the sled down the hill.

• Students should be able to identify balanced and unbalanced forces by viewing and manipulating marbles on a balance scale.

• Students should have a working knowledge of keyboarding skills.

• Students should be aware of internet safety, such as only using the assigned link to begin research.

• Students should be aware of the protocol for constructive criticism and positive feedback, such as being specific and respectful during collaboration.

• Students will know that their elbow partner is a student that sits next to them.

Before: (Days 1-3)

The teacher will introduce the lesson by showing multiple failed snow sledding attempts with a variety of variables in each attempt such as the type of sled, the number and size of people, the slope of hill, etc. See Snow Sledding FAILS & Wipeout Compilation.

The teacher will define the vocabulary words:

1. force-strength or power exerted upon an object

2. balanced-equal distribution of weight

3. unbalanced-unequal distribution of weight

4. variable-something that may or does change

5. size-the spatial dimensions, proportions, magnitude, or bulk of anything

6. direction-the line along which anything lies, faces, moves, etc.

7. speed-how fast or slow an object is moving (equation: speed = distance/time)

8. position-condition with reference to place; location; situation.

9. friction-surface resistance to relative motion, as of a body sliding or rolling

10. air resistance-the opposition of the atmosphere to forward movement

• The students will make flashcards to study the ten terms listed above to be incorporated into their discussions and reflections about manipulating the variables to create the longest snow sled ride.

• The teacher will guide a class discussion about the students' previous experiences with snow sledding, being at the top of a wave on a bodyboard, trying to catch a wave, riding down a hill on a bike, or peddling uphill.

• The teacher will explain to the students that many variables influenced the ease or the struggle of these events.

• The teacher will present balanced and unbalanced forces using marbles and a balance scale.

• When balanced forces act on an object at rest, the object will not move. If the force pushing back is equal, then there will be no movement. To be equal means to be balanced. For example, watch as I (the teacher) put one marble on both sides of the balance scale. The students will observe that the scale is balanced, or equal, and one side is not lower or higher than the other. The teacher will inform students that as long as both sides only have one marble, they are balanced, or equal, and neither side of the balance scale will move.

• Forces that cause a change in the motion of an object are unbalanced forces. To be unbalanced means to be unequal. For example, watch as I (the teacher) add only one marble to either side of the balance scale. The students will observe that the scale becomes unbalanced, or unequal as one side (the side with two marbles) becomes lower. The teacher will inform students that as one marble is added to the other side of the balance scale (the one with only one), the scale becomes balanced or equal again. The teacher will ask, “What happens if I add only one marble to both sides again?" (both sides will have an equal amount). "What happens if I only add one to one side of the balance scale again?"(one side becomes unequal or unbalanced again).

• The teacher will explain to the students that they will soon begin to evaluate the variables such as balanced and unbalanced forces that cause a snow sled to slide down a teacher-created hill and either allow or not allow it to be the longest snow sled ride.

• The teacher will explain that the students will also design their own snow sled based on their knowledge of the terms and relative past experiences, and what they hypothesize (claim) would be a better way to get a longer ride on a snow sled.

• The students will take “silent wait time” (10-30 seconds) to think about what may cause the snow sled ride to end so soon in the video Snow Sledding FAILS & Wipeout Compilation.

• Next, the students will write their idea about the variables that would create the optimal snow sled on a Post-it note.

• The students will then turn and talk to their elbow partners about what they wrote on their Post-it note.

• The teacher will listen in on student elbow partner (student to the left or right of the student) conversations and will be sure to acknowledge on-task thinking, unique ideas, and incorporation of vocabulary taught.

• The teacher will prompt students in peer discussions if any students appear to be off task or have trouble conveying ideas.

• Finally, the teacher will choose a couple of Post-it notes per table and write the students' ideas on chart paper. The teacher will use this to model writing a hypothesis, or claim, as to what snow sled construction would lead to the longest snow sled ride. For example, the teacher may write, “A snow sled made of popsicle sticks and tape would make for the longest snow sled ride. The popsicle stick sled will hold three marbles in the foam cup."

• Students will be assigned to strategically organized groups (3-4 students consisting of high, average. and low ability students) by the teacher.

• Students will meet with their groups and write the hypothesis or claim in their journals for snow sled that would result in the longest snow sled ride.

During: (Days 4-7)

• Students will use the internet to access the links How to make a popsicle snow sled, Top Five Snow Sleds , Homemade sled for 8 dollars with Chromebooks, or portable devices (such as tablets) to begin researching their ideas on how they will design and construct a scaled model of a snow sled to test.

• The teacher will facilitate with the research process as needed to ensure all students are on task and using internet access appropriately.

• Students will review the supplies and determine the materials to be used in construction with their groups.

• Students will collaborate with their groups to draw a design of the snow sled they are constructing and begin to prepare and/or modify materials they will be using to construct their snow sled.

• The suggested snow sled supply materials are as follows: bucket or small plastic bin, plastic bowl, paper bowl, plastic dessert plate, paper dessert plate, frisbee, tin foil (options for sled foundation), scotch tape, ruler, paper, string, Legos, marbles, popsicle sticks, and foam cups. Students will not be required to use all materials but will not diverge from the list of offered material for the initial test of their initial snow sled design and construction.

• The students will use the group design to guide the construction process.

• To build the snow sled, the students will utilize their supplies and build a snow sled that will be released from the same point three times from the marked top of the scaled hill.

• The teacher can use any size or construction of the ramp to test all snow slides for each group.

Keep in mind that all students' snow sleds will be tested on the same ramp. A simple way to create a ramp is to:

1. Clear a space about 10 feet long--this will be the runway.
2. Stack two or three thick textbooks books at one end of the runway.
3. Lean one end of a wooden board on the books and place the other end on the floor.

The teacher will facilitate as students begin the process of testing and documenting the time and distance of each of their snow sled rides. The teacher will use tape and a marker or group color assigned sticky dots to mark the stopping point of each snow sled test. Each group attempt should be labeled with a 1, 2, and 3 to indicate which ride was the longest.

1. One person from each group will take time measurements. A ruler will be used to measure the distance from the release point to the stopping point of the snow sled ride.

2. One person from each group will place their sled at the top of the ramp.

3. One student from the group will release the snow sled without pushing it.

4. One student from the group will use the stopwatch. The watch should be started at the exact same moment the snow sled is released.

• Each group will complete this process a total of three times being sure to document the time and distance in their journals. Students may manipulate one variable at a time (for example adding or taking away marbles) between each snow sled test. At this point, it is important to note any of the snow sleds that are turning over, sliding off the ramp, or having any other issues that cause an unbalance force to act upon the snow sled. Students must document that a variable was changed before it is tested.

• The teacher will ensure that students are collecting at least sixes pieces of data (3 for speed and 3 for distance), and that they are organized by each test.

• The teacher will be sure that students document changing variables (for example adding or taking away marbles) between each snow sled test. Again, it is important to note any of the snow sleds that are turning over, sliding off the ramp, or having any other issues that cause an unbalanced force to act upon the snow sled. The teacher will discuss the positive effects of an unbalanced force such as, 5 properly placed marbles can cause the sled to go faster than 5 improperly placed marbles.

After: (Days 8-10)

• The teacher will introduce the Optimal Snow Sled Experience Presentation Rubric, so that each student is aware of what will be required in the group presentation. The teacher will clear up any misconceptions or answer any questions regarding the rubric.

• Students will then chart their data graphically (teacher choice as to how this will be displayed eg: bar graph, T-chart, etc.)

• Students will then observe which of their snow sled attempts was the longest snow sled ride.

• The teacher will ensure students note which unbalanced and balanced forces influenced each snow sled attempt.

• The teacher will ensure students are evaluating their snow sled design and discussing how variables can be manipulated to improve the snow sled distance and time.

• Each group will then work to create a display and present a group chart of the data collected for each of the three release points. (Chart paper or a multimedia slide presentation, such as Google Slides, can be used. Google Slides will require prior access and sign up with Google, which is free. This program is one of the easiest to navigate for beginning learners, and best for easy access, use, and presentation. Groups can work together on the presentation by assigning certain slides through a shared document or the teacher may choose to allow groups to work from one group computer).

• The teacher will facilitate the class discussion about which group had the longest snow sled ride.

• The teacher will facilitate as students draw the connection between manipulating balanced and unbalanced forces to cause the ride to be longer. For example, 5 marbles would cause more of an unbalance than 0. Five marbles can cause the sled to go faster down the ramp. The unbalanced force guides the snow sled down the hill. As the sled reaches the bottom the marbles scatter out and off the sled, the force becomes balanced again, and the sled stops.

• The teacher will informally assess students’ claim by observing student conversations during group work and ensuring students document the theories and plan of action they discuss in their journals.

• The teacher will informally assess students’ analysis of materials by asking probing questions such as, “What materials may be better suited to provide a longer snow sled ride? What materials make for an uneventful ride, such as friction or air resistance?” The teacher will ensure students document the theories they discuss in their journals.

• The teacher will informally assess the students’ evidence that does or does not support their claim by listening for vocabulary words taught explicitly (force, balanced, unbalanced, variable, size, direction, speed, position, friction, air resistance, and slope). 

• The teacher will informally assess students as the groups observe the speed and distance of their snow sled while ensuring students document the theories they discuss in their journals.

• The teacher will informally assess the conclusion of the snow sled design by observing group discussion after the test of the snow sled.

• The teacher will formally assess the students’ learning objectives by using the rubric to guide and score each group’s claim, design, variables, data collection, and graphic presentation of data collected. The rubric used to guide and score the students' project-based learning of snow sled design, construction, and testing process is Optimal Snow Sled Experience Presentation Rubric. 

• Students may use the algorithm for speed to calculate the speed of their ride since they will already have the necessary components of distance and time.
• Students working at accelerated level who have tested their initial snow sled and found it to be successful, may repeat the process by forming another hypothesis (stating a claim), designing another snow sled, constructing another snow sled, and then testing the snow sled again being sure to only adjust one variable at a time.
• Students will be responsible for maintaining a journal that reflects the initial process, an additional one due to the amount of time they had left, and the effectiveness of the first attempt.

• The teacher will allow peer tutors for completion of vocabulary index cards as they will pertain to discussion and reflection of the snow sled built and tested.

• The teacher will prompt students in peer discussions if any students appear to be off task or are having trouble conveying ideas.

• The teacher may need to facilitate certain groups if there appears to be a lack of cohesiveness to the task in order to facilitate productive collaboration.