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:
What is Gravity?
We begin today's lesson with a KWL Chart. I have created a large KWL chart on a piece of chart paper and have it hanging on the front board. I provide each student with 2 sticky notes, one blue and one yellow. I ask them to write down everything they know about gravity on the yellow sticky note. I give them about 2 minutes to record their ideas on the sticky note. After 2 minutes, I ask students to share what they have recorded. One student says it keeps us on Earth. Another student says it pulls things down. After I have a few students share, I call one group up at a time to place their sticky notes on the chart under the K (What I already Know).
As I am calling groups up to put their yellow sticky notes up, I ask them to write down at least one thing they would like to know, or learn, about gravity throughout this unit. I give them about 2 minutes to write down what they would like to learn and then ask them to go place it under the W (What I Want to Learn) section of the chart. We do not go over these, this is information for me to look over so I can incorporate the information they would like to learn throughout the lesson. Many of the questions are about who discovered gravity, what year it was discovered, etc. As students or groups finish activities early throughout the unit they can look up these answers and inform the class then I record them on the chart.
Experiencing Gravity First Hand
I throw a ball up in the air and catch it in my hand. I ask, why did the ball come down when I threw it up? Students tell me gravity pulled it down. I ask, is gravity pulling on me right now? They say yes. Well I don't feel it, I respond and ask why. Students tell me that it can't be felt and it is so light I don't notice it. I explain to students that gravity is a constant force on Earth. It pulls things down towards its center. Because there is always the same amount of gravity acting on our bodies, we are so used to it that we don't even notice it. I tell them that gravity is very strong and I would like to show them how strong. In the video of teacher directions for overcoming gravity activity you will hear me give the following directions:
I circulate to watch students try to accomplish this task. I stand next to any student who says they can do it and watch their movements closely. This is an impossible task so any student who says they can do it is usually moving their feet or leaning forward. I call up a couple of students to try it in front of the class. In this video of student trying to overcome gravity, the student leans forward slightly every time. It is easy to see as a person on the outside looking it but sometimes they don't realize they are doing it. In the video of student 2 trying to overcome gravity, this student is trying to stand quickly which is what a lot of students try. They think if they do it fast enough their momentum will get them up...it doesn't work.
I explain to them that we have come up with ways to overcome gravity that come so naturally to us that we don't even know we are doing them. For example, leaning forward in your chair when you get up. Throughout this unit, we will investigating the pull of gravity relating to a variety of objects, and investigating ways to overcome gravity here on Earth.
Introducing the Engineering Project
Our first investigation related to this is an engineering project. The project requires students to create a structure to move a marble from the top, to a cup at the bottom, using only the force of gravity. I place the Engineering Design Project - Marble Mover Task Sheet on the overhead while I go through it with the students. The object of the activity is to build a structure that incorporates various ramps, jumps, and loops made of cardboard, paper towel rolls, and toilet paper rolls. Groups earn points based on the number of times the marble changes direction, jumps up to another ramp, goes through a loop, and finally for making it down the entire structure and ending up in the cup at the bottom.
Starting the Engineering Design Process
After going over the task sheet, I place the Engineering Design Process flow chart on the overhead and review the steps with the class. I point out that research and planning are the first two steps and that they must be completed prior to getting materials and building.
I hand each student a card with a number, 1 - 5, written on the back. After all students have cards, I tell them that those with a 1 will work together on the project, those with a 2 will be together, and so on. I provide each group with a copy of the Engineering Project Planning Sheet and a lap top. They spread out around the room and begin researching. I circulate to check sites that they are using as well as offer hints on what might be some good things to research. I suggest things such as "marble ramps" and "creating loops in a roller coaster".
As students are researching, they begin drawing out a design of what they would like their structure to look like. Their drawings must be easy for me to see what their plan is. If I see any that do not clearly illustrate a model of their structure, I ask them to redo it before having me check it to sign off on.
As students begin finishing their planning, I check their sheet and sign off. Once they have it signed off by me, they can begin gathering their materials to start constructing their structure. Each group begins with a large piece of cardboard (all are the same size) that will be the back of their structure. All ramps and loops will be taped to this piece of cardboard. They all take a roll of box tape, a cup, and several paper towel and toilet paper rolls, as well as smaller pieces of cardboard they can use.
Groups spend about 20 minutes researching and planning, and the remaining 20 minutes building. They will finish the project, begin testing and making adjustments to it, and then share it with the class, during tomorrow's science lesson.
I thought it was interesting how groups started building. You can see in the video of students beginning their marble movers that this group puts one ramp on at a time and tests it. They build the marble mover upright the entire time. In video 2 of students beginning their marble movers, this group is beginning their marble mover laying the board down and laying out all of their ramps as in their plan. It will be interesting to see how they turn out different.