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Inclined Plane - Pull Weight

Name of Corresponding Unit Plan: Inclined Plane - Uses

Grade Level: 4-8

VT Grade Expectations
VT S:5 Students demonstrate their ability to REPRESENT DATA by displaying and labeling data for separate trials/observations.
VT S:6 Students demonstrate their ability to ANALYZE DATA by interpreting patterns or trends in data.
VT S:7 Students demonstrate their ability to EXPLAIN DATA by providing a reasonable explanation that accurately reflects data.
VT S:21 Students demonstrate their understanding of Force by investigating variables that change an object's speed, direction, or both, and identifying and describing the forces that cause the change in motion.

NY Standards
NY Standard 1: Mathematical Analysis
Key Idea 1: M1.1 Use algebraic and geometric representations to describe and compare data.
Key Idea 2: M2.1 Use deductive reasoning to construct and evaluate conjectures and arguments.
NY Standard 1: Scientific Inquiry
Key Idea 1: Clarify ideas through reasoning, research, and discussion
Key Idea 3: S3.1 Use various means of representing and organizing observations

Content Areas: Science

Recommended Length/Duration: 30-50 minutes

Learning Goals: Students will measure the affect different inclined planes have on lifting a Load.

Description/Sequence:

  1. Remind students that whenever a machine decreases one thing, it must increase another.
  2. Demonstrate how to set up an inclined plane at different angles. Each time the Load should be raised the same height; only the length and angle of the ramp will change. As the angle of the plane becomes more acute, it will become longer.
  3. Use the spring scale to weigh the Load. Demonstrate how the pull weight should be read as the Load is moving along the ramp.
  4. Review the worksheet with students and the data they will need to collect.
  5. In small groups or as a learning center, have students set up each inclined plane system measuring the height and length of the plane.
  6. Students will measure the pull weight on the spring scale as they pull the Resistance up the ramp. They should repeat the process several times and take the measurement that appears most constant.
  7. Students can calculate the Mechanical Advantage of the inclined plane by dividing the Resistance Weight by the Effort Weight. Repeat for each inclined plane system.
  8. When everyone has completed the activity, discuss their findings. Guiding questions may include:
    • Which system had the highest/lowest mechanical advantage?
    • Did there seem to be a best angle for lifting?
    • What are the advantages and disadvantages of each ramp?
    • Is there a way to determine mechanical advantage without actually measuring the pull weight?
  9. Student data may vary, but should support the fact that Ideal Mechanical Advantage can be determined by dividing the Effort Distance by the Resistance Distance. Generally, the more acute the ramp angle, the greater the mechanical advantage. However, friction will make the Actual Mechanical Advantage a bit less than the Ideal Mechanical Advantage.

Assessments Assessment can be informal based on participation and general understanding, or more formal in terms of accuracy of measurements and calculations.

Materials/Resources:
Inclined Plane - Pull Uses Worksheet (pdf)
Rigid ramps about 15 cm wide and 100 cm long, Resistance (block of wood, science weight, heavy toy car), spring scale, meter stick or tape measure

Special Considerations: It is best to try and use easy numbers to calculate. A resistance weight of 1 kg is hefty enough to provide some resistance, but a nice round number for calculations.