Simple Machines: How Can You Lift a Heavy Object?

Transcription

1 Simple Machines: How Can You Lift a Heavy Object? There are 3 heavy objects that need to be lifted: a wagon, a bucket of sand and my desk. You need to select 1 of these objects and think about how you might lift it. Draw a picture of your idea and explain your drawing. 1 of 10

2 Suggested Grade Span 3 5 Task There are 3 heavy objects that need to be lifted: a wagon, a bucket of sand and my desk. You need to select 1 of these objects and think about how you might lift it. Draw a picture of your idea and explain your drawing. Big Ideas and Unifying Concepts Cause and effect Design Models Systems Physical Science Concepts Motion and forces Transfer and transformation of energy Design Technology Concept Use of tools Mathematics Concept Diagrams Time Required for the Task 45 minutes. Context This task is a preassessment given at the beginning of a unit on simple machines to third graders. It was developed as a means to assess what students already know about lifting and moving objects as well as about using simple machines to make work easier. During the course of the unit, students will investigate each of the six simple machines: lever, inclined plane, wheel and axle, screw, wedge, and pulley. 2 of 10

3 Students will also learn how energy is needed to do work and that work is defined as moving an object to a new location. During the course of these investigations, students will also explore the forces of motion: inertia, gravity, friction, and push and pull. This task will then be given again to assess how students understanding has deepened. Throughout this unit, students will practice a number of science process skills, such as developing testable questions, making predictions, planning and conducting investigations, controlling variables, collecting/recording/analyzing data, drawing conclusions and communicating results. What the Task Accomplishes This task is designed to preassess students prior knowledge and understanding of simple machines and the work they do. It can also be used as a postassessment to assess what students have learned about the simple machines and how they make work easier. How the Student Will Investigate This particular task does not ask students to perform an actual investigation. Rather, students need to apply their prior understanding and knowledge of simple machines to solve a problem. Students will need to decide which object they want to lift. Then they need to think about how they might lift it. Next, they should draw a detailed picture of their idea and explain in words how it works. This task could then be used during the course of a unit on simple machines where students would then actually try to lift one of these objects using the simple machines they have experimented with. Interdisciplinary Links and Extensions Math During the course of the unit, students use such tools as spring scales to measure work and effort. They also weigh (using balance scales) and measure the items movement as well as the distances traveled. Movement Students can create a human machine by having each student stand in a line across the room. Give the first student a heavy book. Each student must perform a different movement to pass the book along the line until it gets to the end. Language Arts Students can write and illustrate big books about the six simple machines and how they are used in everyday life. You may wish to also have students research inventions and inventors. 3 of 10

4 Good children s books about simple machines and inventions include the following titles: Machines at Work, by Byron Barton The Way Things Work, by David Macauley Making Things Move, by Neil Ardley Stories Behind Everyday Things, by Jane Polley and Peter Chaitin Inventor s Workshop, by Alan J. McCormack Teaching Tips and Guiding Questions You may wish to do a KWL with students before passing out the preassessment to find out what they already know and to set the stage for this task. (K = What do you Know now? W = What do you want to know? L = What did you Learn?) Here are some possible guiding questions to ask students: What would make lifting this object difficult? What would make lifting this object easier? What things have you seen before that might help with this problem? How will you draw your idea? How will you describe your idea? Why do you think your idea will work? Concepts to be Assessed (Unifying concepts/big ideas and science concepts to be assessed using the Exemplars Science Rubric under the criterion: Science Concepts and Related Content) Scientific Method: Students observe and explain cause-effect relationships, with some justification, using data and prior knowledge. Students see that how a model works after changes are made to it may suggest how the real thing would work if the same thing were done to it (models). Physical Science: Motion and Forces; Transfer and Transformation of Energy: Students see that simple machines enable us to move an object from one location to another and that simple machines can make work easier. Design Technology Use of Tools: Students see that tools are invented to extend the ability of people (to make things, to move things, to shape materials). Mathematics: Students use diagrams appropriately. 4 of 10

5 Skills to be Developed (Science process skills to be assessed using the Exemplars Science Rubric under the criteria: Scientific Procedures and Reasoning Strategies and Scientific Communication Using Data) Scientific Method: Predicting/hypothesizing, proposing a solution, drawing diagrams and explaining the solution. Other Science Standards and Concepts Addressed Scientific Method: Students raise questions, predict, plan investigations and control variables. Scientific Theory: Students look for evidence that explains why things happen and explain phenomena in the physical world. Physical Science Motion and Forces: Students observe that forces such as push and pull enable objects to move or stop and that friction affects the motion of an object. Physical Science Transfer and Transformation of Energy: Students observe that energy is needed to do work and that there are two types of energy: potential and kinetic. The Designed World: Students observe that tools extend the ability of people (to make things, to move things, to shape materials) and that manufacturing requires a series of steps and, depending on the task, careful choice of materials (based on their characteristics). Suggested Materials For this particular task students will need only the preassessment prompt and pencils. Possible Solutions A correct solution includes a reasonable idea about how to lift the object, a detailed drawing of the idea (with labels if appropriate) and an explanation. Task-Specific Assessment Notes Novice A drawing of the idea is included, but there is not enough detail to indicate how the object will be lifted. An explanation is started but is not adequately developed to describe how this idea will make lifting the object easier. Prior knowledge about simple machines appears to be very limited. There is some evidence that the student understands that a magnet could provide the force to lift the desk. 5 of 10

6 Apprentice A clear drawing of the idea is included, and there is some detail to indicate how the object will be listed. An explanation is included but does not completely describe how the desk can be lifted with the piece of wood. The drawing indicates that a rock is used as a fulcrum, but this important aspect is not included in the explanation. Prior knowledge (of levers) and some conceptual understanding of simple machines is evident, but the student appears to have had limited experience with them. Practitioner A detailed drawing of the idea is included. The picture clearly shows how the object can be lifted. An explanation is included that completely describes how the desk can be lifted. Prior knowledge about simple machines (pulleys) is evident. Expert A detailed and labeled drawing of the idea is included. The picture clearly shows how the object can be lifted up the stairs. An explanation is included that completely describes how the wagon can be lifted up the stairs and why this makes lifting easier (the board is flat). Prior knowledge about simple machines (inclined planes) is evident. 6 of 10

7 Novice 7 of 10

8 Apprentice 8 of 10

9 Practitioner 9 of 10

10 Expert 10 of 10