The Why Behind Teaching This:
This unit covers standard 5-PS2-1: Support an argument that the gravitational force exerted by Earth on objects is directed down. During the unit, students will investigate a variety of objects to see that the force of gravity is constant on Earth and pulls things down towards its center. We will also be investigating a variety of ways to overcome gravity.
Several of the lessons in this unit are engineering design projects requiring students to follow the steps of the engineering design process to construct a project. These projects address standard 3-5-ETS1-1: Define a simple design problem reflecting a need or a want that includes specified criteria for success and constraints on materials, time, or cost. It also addresses engineering standard 3-5-ETS1-2: Generate and compare multiple possible solutions to a problem based on how well each is likely to meet the criteria and constraints of the problem. There are also several experiments in the unit which address standard 3-5-ETS1-3: Plan and carry out fair tests in which variables are controlled and failure points are considered to identify aspects of a model or prototype that can be improved.
This specific lesson addresses the science standard related to gravitational force, standard 5-PS2-1, by having students use gravitational force to move their marble down a structure to the bottom. They will also need to be creative in ways to try and overcome gravity and get their marble to move up at certain points. This lesson also addresses both engineering standards by having students follow the steps of the engineering design process to plan, build, and test their marble moving structure prior to sharing the final project with the class.
The goal of today's lesson is for students to create a structure that uses the force of gravity to get a marble from the top of a structure, to a cup at the bottom, and to incorporate ways to overcome gravity within their structure design.
The success of students will be measured on the movement of the marble through their structure.
Preparing for Lesson:
Building of Structures (Continued from day 1 lesson)
Students were placed into groups and completed the first two steps of the engineering design process during the Marble Mover (Day 1) Lesson. They completed their planning sheets and gathered materials to begin building their structures. Before they get back into their groups to finish building, I review the Engineering Design Project - Marble Mover Task Sheet with them, pointing out the section about how many points they will earn for each time the marble changes direction, jumps up to a new ramp, or goes through a loop. The group that earns the most points will win the engineering design challenge.
After we review the goal, students get back into groups, gather their materials, and begin building again. I circulate to ask questions, make sure students are safely using the resources, and staying on task. I put a timer up on the overhead from the classroom timer website so that students can keep track of the time they have remaining. They spend the next 40 minutes building and testing their structure.
As you can see in video 1 of students building the marble mover, the group is planning ahead by testing it before taping it on. They move it around to find which location works best and then tape it on In video 2 of students building the marble movers, you can see that groups have to test their structures as they build so that they can make adjustments. When their marble is not making it down a ramp they have to bend and adjust the ramp. In video 3 of students building marble movers you can see how excited one group is when they have it perfected so that their marble makes it down the ramp and into the cup.
As groups are building and testing, I remind them that as they make adjustments to their plan, they should be adding these changes to their planning sheet. I tell them to make the changes in a different color pen or marker. I do not want them erasing and adding new marks because I like to see how their original idea had evolved into the end product.
The picture above shows how this groups decided to take out their loop and make a couple more direction changes and a jump instead.
Drawing and Labeling a Model
When their 40 minutes of building is up, I give each group a copy of the Marble Mover Test Sheet and ask them to draw a model of their structure and label each jump, loop, and change in direction. I will be using this sheet to track the number of points earned by each group. Having a model and labels will help me know what they plan on happening at each point. Sometimes I may not see the marble jump and knowing that they had attempted to make it jump will help me focus more at that moment so I can see even the slightest jump.
Each group comes up one at a time and releases their marble at the top of their structure. I watch to see how many successful jumps, loops, and changes in direction their marble makes. If their marble did not make it in their cup, I allow them to try one more time but they cannot make any changes to it at this point. After each group tests their structure and their marble gets to the end, they describe how gravity impacted the marble through the entire course. When it falls into another ramp, gravity is pulling it down. When it jumps, then comes down onto another ramp, gravity is causing this.
A couple of groups could not get their marble to make it even with a second try. We discuss what prevents the marble from making it. In one case there was a gap that was too large between two ramps and the marble was falling. We discuss how gravity is pulling down on the marble at all times, including when it goes between those ramps. Gravity pulls it down making it fall in the gap. In another case, the group had made a jump that was too large. The marble did not have enough speed to get over the upward arch and into the next ramp. We discussed this and another group had suggested they put a longer or steeper fall before the jump to help the marble gain more speed before attempting it. Another group said to make the arch less dramatic or not as steep and the marble would probably make it.
I add up the points each group earned and announce the winner.