This Concept Builder is designed to target student understanding of Pascal's Principle and the operation of a hydraulic lift. Three activities are provided, each of which approaches the topic from a slightly different angle. The opening activity - Paragraph Completion - focuses on the textbook-style description of Pascal's Principle and its application to a hydraulic lift. It forms a good confidence booster. Success is nearly guaranteed to the patient student. There is no limit on the number of allowed tries and feedback is immediate once the Check Answer button is tapped. Students are told the number of correct answers but not which answers are correct.

The second and third activities focus on the mathematical relationships associated with a hydraulic lift. Each question provides a simple diagram with two unequal-area pistons. The areas of the two pistons is given; values are selected such that the ratio of one area to the other area can be determined via head math (for most students). A force is exerted downward on the piston of smaller area. In the second activity (The Hydraulic Lift). students must determine the force exerted upward on the larger piston. In the third activity (Thinking Proportionally), students must determine how many times greater (or smaller) that the force on, the pressure at, and the displacement of the second piston is relative to the first piston. In both the second and third activities, answers are selected by tapping on a button to toggle through a collection of possible numerical answers.

Questions are very suitable for all levels. Even the numerical questions use "kind" numbers. For those teachers seeking more difficult problems, they can be found in the Fluids chapter of our Calculator Pad section.

This Concept Builder consists of 25 different questions that are organized into 9 different Question Groups. The questions and question groups are organized into three different activities. The activities are differentiated as follows:

• Paragraph Completion  Question Group 1: Students complete a paragraph with 8 blanks using a word/phrase bank in order to communicate an understanding of Pascal's Principle and its applications to a hydraulic lift.
• The Hydraulic Lift  Question Groups 2-5: If given the areas of the two pistons of a hydraulic lift, students must determine the output force at one end when given the input force.
• Thinking Proportionally Question Groups 6-9: Students use Pascal’s Principal and proportional reasoning to predict the relative force on, pressure at, and displacement of a piston of a hydraulic lift when given the areas of the two pistons.

Teachers are encouraged to view the questions in order to judge which activity is most appropriate for their classes. We recommend doing all three activities. Before using the Concept Builder with classes, we recommend that teachers attempt each of the activities in order to determine which are most appropriate for your classes and what pre-requisite understanding a student must have in order to complete it. Alternatively, the Questions are provided in a separate file for preview purposes (accessible by Task Tracker teachers only). 

In order to complete an activity, a student must correctly analyze each question in that activity. If a student's analysis is incorrect, then the student will have to correctly analyze the same or very similar question twice in order to successfully complete the activity. This approach provides the student extra practice on questions for which they exhibited difficulty. As a student progresses through an activity, a system of stars and other indicators are used to indicate progress on the level (displayed for Task Tracker users). A star is an indicator of correctly analyzing the question. Once a star is earned, that question is removed from the queue of questions to be analyzed. Each situation is color-coded with either a yellow or a red box. A red box indicates that the student has incorrectly analyzed the question and will have to correctly analyze it twice before earning a star. A yellow box is an indicator that the question must be correctly analyzed one time in order to earn a star. Once every question in an activity has been analyzed, the student earns a Trophy which is displayed on the Main Menu. 

The most valuable (and most overlooked) aspect of this Concept Builder is the Help Me! feature. Each Question Group is accompanied by a Help page that discusses the specifics of the question. This Help feature transforms the activity from a question-answering activity into a concept-building activity. The student who takes the time to use the Help pages can be transformed from a guesser to a learner and from an unsure student to a confident student. The "meat and potatoes" of the Help pages are in the sections titled "How to Think About This Situation:" Students need to be encouraged by teachers to use the Help Me! button and to read this section of the page. A student that takes time to reflect upon how they are answering the question and how an expert would think about the situation can transform their naivete into expertise. 

 

 

We do not have a lot of resources on the topic of Fluids at The Physics Classroom website. What we do have is listed below. We hope to be adding more in the future.