Lesson: Hydrostatics

Overview of Lesson

This lesson introduces pressure and pressure measurement in the context of a fluid that is in hydrostatic equilibrium.

Benefits of this Lesson

  • Learn foundational concepts: pressure, hydrostatics, fluid particle, and head
  • Learn how to calculate gage, vaccuum, and absolute pressure
  • Learn how to calculate pressure variations in hydrostatic fluids
  • Learn how to solve manometer problems
  • Learn how to select and use pressure gages


1. Essential Concepts. Learners know these concepts:
* hydrostatic condition
* fluid particle
* pressure (subconcepts: gage pressure, vacuum pressure, absolute pressure, atmospheric pressure)
* head (subconcepts piezometric head, piezometric pressure)

2. Seminal Eqns.
* Learners can apply Eqs. (3.3a) and (3.3b) to relate pressure values
* Learners can derive the hydrostatic differential equation. Eq (3.4).
* Learners know:
* Hydrostatic Equation (Eq. 3.4)
* Manometer Equation. Eqns (3.18, 3.19)

3. Pressure Measurement Instruments. Learners know "how things work" for these devices:
* U-tube manometer
* Mercury barometer
* Bourdon tube gage
* piezometer

Plan (steps to reach the goals)

1. Goal Setting.
Recommend: Write down personal goals for this lesson. Ask yourself, what do I want? What are my motivations for studying engineering? Make your goals specific (i.e. measurable) and challenging. For more information, see "how to write goals."

2. Foundational concepts. (p. 33-37).
a. Learn the foundational concepts listed in the goals. I recommend that you build your own mreac sheets. Resources to help you include the examples of mreacs (see hyperlinks in goals).
b. Practice by doing problems such as 3.1 to 3.6. (posted solutions: 3.1, 3.5).

Classroom activities we may do include: Pressure in a basketball. Contact Patch.

3. Hydrostatic Differential Equation. (p. 37 to 38).
Learn how to derive the hydrostatic differential eqn from memory. I recommend that you create your own documentation and then practice presenting the derivation to people until you have it down solidly. Resources to help you include
- a webpage that explains How to learn a derivation
- a (Video plus handout) that shows how to do the derivation.

4. Hydrostatic Eqn. (p. 38 to 39)
a. Learn the hydrostatic equation. I recommend that you build your own netmad—see example.
b. Practice doing problems such as 3.7 to 3.27 (posted solns: 3.7, 3.9, 3.10, 3.11, 3.13, 3.18.) Resources to help you include:
- (Example 3.2 Video, handout)
- (Example 3.3 Video, handout)

5. Manometer Eqns. (p. 44 to 47).
a. Learn the manometer equations. I recommend that you build own summary notes (e.g. NETMAD). A resource to help you is the Manometer Equation handout.
b. Make sure you can do text problems such as 3.28 to 3.45 (posted solns: 3.29, 3.31, 3.40, 3.42). As always, I recommend that you do problems yourself and then correct in red pen.

6. Pressure Measuring Instruments. (p. 43 to 48).
a. Make sure that you can hit goal 3. I recommend that you construct "how things work" documentation. This link shows an example of this type of documentation: (example).

7. Lesson Review (Reflective Thinking)
a. Assess your learning using this form. Print1 and staple the form to front of your homework. Resource: (How to write an SII).
b. Assess this lesson using this (form).

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