The Why Behind Teaching This:
Unit 3 addresses standards related to the transfer of energy and matter between organisms in an ecosystem. The unit begins with identifying what solar energy is and what two forms of energy solar energy provides to life on Earth. This is an important foundation for understanding standard 5-PS3-1: Use models to describe that energy in animals' food (used for body repair, growth, motion, and to maintain body warmth) was once energy from the sun. We build on this knowledge throughout the unit in other lessons related to photosynthesis and how animals use the energy they get from food. In this unit students will also be conducting experiments to gather evidence to support their belief that plants get the materials they need for growth from either water, air, or the soil. This is covered in standard 5-LS1-1: Support an argument that plants fet the materials they need for growth chiefly from air and water. Students will be creating food chains and food webs to describe the movement of matter among organisms in an ecosystem. This is covered in standard 5-LS2-1: Develop a model to describe the movement of matter among plants, animals, decomposers, and the environment.
I combined these three standards all into unit 3 because teaching them together allows students to see how they are all connected. The energy that plants get from the sun is stored in their parts until animals consume them. Plants cannot absorb this energy and reproduce without other materials from the environment such as carbon dioxide from the air, and water and nutrients from the soil. The animals that consume the plants use part of the energy for growth, reproduction, etc. but they also store some of the energy. That energy is then passed on to other animals once eaten. All of the energy that is available in an ecosystem can ultimately be traced back to the sun. Teaching all of these standards together, instead of in isolation of each other, makes that connection easier to see.
This specific lesson is linked to standard 5-PS3-1: Use models to describe that energy in animals' food (used for body repair, growth, motion, and to maintain body warmth) was once energy from the sun. This lesson is laying the foundational knowledge that solar energy can be transformed into other forms of energy, in this case electric energy which is then used for movement (kinetic energy). Once students have this background knowledge, we will begin applying it to plants ans animals.
Students are working through the steps of the engineering design process in this lesson which is covering standard 3-5-ETS1-1: Define a simple design problem reflecting a need or want that includes specified criteria for success and constraints on materials, time, or cost. They were taught the design process in an earlier lesson using the Engineering Design Process Template.
The goal of this lesson is for students to build a car that converts energy from the sun into electric energy that powers the cars motion, and to draw and label a model explaining the transfer of energy.
Students will demonstrate a clear understanding of the goal by submitting their labeled model for grading. All descriptions labeled must be accurate and show they truly understand how energy is being transferred through the system.
Preparing for Lesson:
Prior to this lesson, you will need to order solar panels for the cars you plan to build. I ordered kits from Junior Solar Sprint.
Have a copy of the Engineering Design Project - Solar Powered Car Task Sheet copied for each group and one extra copy to put on the overhead to review with the class.
Have a copy of the Engineering Project Planning Sheet copied for each group. Each group will also need the following materials:
A table with extra materials that can be chosen from will also need to be available. Some suggested materials might be, small boxes, cups, empty water bottles, paper towel rolls, rubber bands, tape, etc.
Students will need access to a computer for this portion of the lesson. They will be researching designs for their car and completing the rest of the planning sheet. If you do not have laptops or classroom computers available for all groups, you could do the research on the overhead and allow time for students to discuss and plan after each site you visit.
Showing a Real Solar Powered Car Race:
I begin today's lesson by showing the students a real solar powered car race. I chose to begin the lesson with this video because many students have never seen a real solar powered car. Showing this video will allow me to point out certain things that will help them in the engineering activity before even telling them that they will be building a solar powered car.
After showing the short video, I ask students where the solar panels were located on the car. This may seem obvious but some students do not know what solar panels look like and may not be sure. We point out the black surface on the top of the car. I also ask students why they think the panels are black in color. This is review from the previous lesson, solar energy: colored envelope experiment. The black will absorb more light then other colors. I ask students why each car only had a small enclosed area for the driver to sit, why the area isn't larger. This could be for a couple of reasons, one may be to make it as light as possible. Another reason may be that the solar panels need to be exposed to the sun and a larger surface for the driver would cover them up.
After our discussion about real solar powered cars, I display the Engineering Design Project - Solar Powered Car Task Sheet for this experiment. I explain the goal for this engineering activity is to create a car that transfers solar energy into electric energy to move the car. I tell students that we will be testing each car three times and taking the best time for each car. I show students the materials they have available to them such as the wood, axles, wheels, and the solar kits. After showing the materials they must use, I explain that the other materials on the table, are for them to choose from when planning their design. I have things on my table such as cups, boxes, craft sticks, paper towel rolls, and water bottles. I go over the limitations from the task sheet as well.
Getting Into Groups:
To divide students up into groups, I have all names of the students written on craft sticks. I choose the first five sticks. Those five people are the material managers for the five groups. Each group needs three more people. I allow the five material managers to choose three craft sticks from the cup and hold them, without looking at them. Once all five students have three sticks, one at a time, I have them read the names of those in their group. It i important for students to work with a variety of students in class because in the real world, they will find that they have to work with a variety of personalities and types of people. I do allow students to choose their groups sometimes, but if they are always allowed to choose, they would always work with the same people.
Dividing them into groups in this way does make it possible that you may end up with a group of all ESE or ELL students which I do not like. If I see that this has happened, I will kindly ask two students to switch groups. Ideally, I like to have one high student, 2 low students, and 1 average student in a group together.
Using the Solar Powered Kit to Assemble:
Students get into their groups and find a work space in the room, away from other groups. I give each group a copy of the task sheet we went over in the warm up for students to refer to, along with an Engineering Project Planning Sheet. I give them a few minutes to fill in the top portion of the planning sheet with the information about group members roles, and with the information from the task sheet.
As they are filling in their planning sheet, I provide each group with one solar powered kit which contains the solar panel, motor, mounting bracket for the motor, and screws, alligator clips, and wires for connecting it all together. I found a PowerPoint showing step by step directions on how to attach the solar panel to the wood and connect the motor. I have students measure and mark the lines as described in slides 20 - 25 of the powerpoint. They do this the day before and I cut the basal wood at home to help save time. By cutting them at home, I am also taking out the risk of injury with use of sharp scissors or a utility knife.
I provide each group with a board and they glue the panel support on as indicated in slide 26. I go through slides 27 - 50 with the class modeling how to complete each step to set up the foundation for the car. Once it is all put together the motor will be sitting in the metal holder which is screwed into the wood base. Groups build their cars around that. You can see in the video of group setting up car that they are responsible for attaching all of the parts to their car.
Research and Planning:
Slides 63 -70 on the PowerPoint are examples of completed cars. I show those slides to the students before letting them research on their own. As I pass out a laptop to each group, I offer some suggestions for things to research. I tell students that they might want to research best designs for solar powered model cars, how to angle a solar panel for 9:00 a.m. (this is what time we will be testing), and I suggested looking up Junior Solar Sprint Races that have taken place so they could see what some of the car designs were like.
The remaining 15 minutes of this lesson is spent researching ideas for a design for their car. Students complete the rest of the planning sheet as they research. When they have the planning sheet complete, including a model drawing, they will get it approved by me. Groups will not be allowed to get their materials to begin constructing their car until I have approved their design. Some Groups do not finish and will thus have to extend some of the planning into day 2.