Points Rationale 4 Student’s response is acceptable and demonstrates understanding that a prototype is a working model used to test a design concept by making actual observations and necessary adjustments 3 Student’s response has at least one flaw in understanding that a prototype is a working model used to test a design concept by making actual observations and necessary adjustments 2 Student’s response has more than one flaw in understanding that a prototype is a working model used to test a design concept by making actual observations and necessary adjustments 1 Student’s response is lacking in understanding that a prototype is a working model used to test a design concept by making actual observations and necessary adjustments 0 Student does not attempt to answer PTS: 4 7. ANS: Answers will vary, sample response: ADVANTAGES: models provide a visual representation of a conceptual design; models can be built first, tested and modified before building the real thing; models can be more cost-effective; models could be a time-saver in the long run. DISADVANTAGES: some real problems may not manifest themselves in models that do show up in the real thing; models must be constructed carefully to be a realistic representation of the real thing; models are predictions and estimations, some people may not find them believable. Points Rationale 4 Student’s response lists 2 acceptable advantages and 2 acceptable disadvantages 3 Student’s response is missing an advantage or disadvantage AND/OR lists an unacceptable advantage or disadvantage 2 Student’s response lists only advantages or disadvantages and are unacceptable 0 Student does not attempt to answer PTS: 4 8. ANS: Answers will vary, sample response: An accelerometer is a measuring tool that allows you to measure how much something is speeding up or slowing down. It can even tell if you have tilted or turned something, like your iPad or Wii controller. Points Rationale
Accelerometers Objective: • To measure the acceleration environments created by different motions. Science Standards: Physical Science - position and motion of objects Unifying Concepts and Processes Change, Constancy, & Measurement Science and Technology - abilities of technological design Science Process Skills: Communicating Measuring Collecting Data Mathematics Standards: Communication Number & Number Relationships Measurement Computation & Estimation Activity Management: This activity provides students with the plans for making a one-axis accelerometer that can be used to measure acceleration in different environments ranging from +3 g to -3 g. The device consists of a triangular shaped poster board box they construct with a lead fishing sinker suspended in its middle with a single strand of a rubber band. Before using the device, students must calibrate it for the range of accelerations it can measure. The pattern for making the accelerometer box is included in this guide. It must be doubled in size. It is recommended that -3 -2 -1 0 1 2 3 Students construct a device that can measure acceleration environments from +3 to -3 9. Lightweight poster board (any color) 3 "drilled egg" lead fishing sinkers, 1 size Masking tape Rubber band, #19 size 4 paper clips Scissors Straightedge Ballpoint pen Pattern Hot glue (low temperature) several patterns be available for the students to To save on materials, students can work in teams to make a single accelerometer. Old file folders can be substituted for the poster board. The student reader can be used at any time during the activity.
Accelerometer Test Answer the following as you test your accelerometer using complete sentences. Accelerometer Team Names: ___________________________ ___________________________ ___________________________ ___________________________ Test your accelerometer by jumping in the air with it a few times. What happens to the position of the sinker? Answers will vary. They should include a discussion as to how the sinker moves appears to move down as they jump up, stops moving at the top of their jump and moves down when they land. What “g” forces did you encounter in your jumps? Answers will vary. Where else might you encounter g forces like these? Answers will vary. Suitable responses will include such things as roller coasters and traveling over a hill in a car. Explain how your accelerometer measures different accelerations. Because of inertia, the sinker will try to stay where it is and this will stretch the rubber band. Eventually the rubber band will be able to move the sinker. The rubber band obeys Hooke’s Law which states the restorative force is proportional to the amount of stretch. By measuring how much the rubber band has to stretch before it moves the sinker you can determine your acceleration. Small accelerations will not stretch the rubber band as much as large accelerations.
blocks of texts. Performance Effectively delivers to the audience by making eye contact with audience and adds to text on slide. Uses voice variation; interesting and vivid to hear. Makes eye contact with the audience, but does not add to information provided on slide. Speaks clearly and confidently. Makes very little eye contact and read off of slide. Uses incomplete sentences. Little or no attempt is made to stay on the topic. Does not consider audience. Difficult to understand. Teamwork Presentation shows that each person delivered key information and evidence of rehearsal is evident Presentation shows that 75% of the team delivered key information and evidence of rehearsal is evident Presentation shows that 50% of the team delivered key information and evidence of rehearsal is evident Presentation shows that 25% of the team delivered key information and evidence of rehearsal is evident Prototype Meets Constraint The prototype measures 10x5 cm as a The prototype does not meet the
specified constraint. constraint of 10x5 cm. Function The prototype does measure accelerations performing with 100% consistency. The prototype measures accelerations consistently 80% of the time. The prototype measures consistently <80% of the time. The prototype does NOT measure accelerations Sensitivity The team presents evidence that supports the fact that their prototype is more sensitive than the large- scale model. The team has not evidence that supports the fact that their prototype is more sensitive than the large-scale model Engineering Design Process (EDP) The team’s prototype is clearly the result of the teams successful application of the EDP The team’s prototype is clearly NOT the result of the teams application of the EDP