Pressure In Liquid

Subject: Class: Date: Time: No. of students: Learning Area : Learning Objective:

Physics Form 4UM 1 June 2009 10.00 am – 10.30 pm (30 minutes) 37 students Forces and Pressure Understanding Pressure in Liquids

Learning Outcomes: At the end of the lesson, a student is able to: A

Master content knowledge a. State that depth is directly proportional to pressure in a liquid b. Sate that density is directly proportional to pressure in a liquid c. Construct the formula P=hρg from both the relationships (a) and (b) above, where P is pressure in liquid, h is depth, ρ is density of liquid and g is the acceleration due to gravity and the equation P=F/A where F is force and A is contact area. d. Solve 2 numerical problems involving the equation P=hρg

B

Master Scientific Skills/TSTS a. Design and carry out an experiment in groups to find the relationship between pressure in liquid, depth and density of liquid given a mineral bottle, tray and oil,

C

Demonstrate Scientific Attitudes and Noble Values a. Actively participate in carrying out the experiment based on agreed upon procedures as a team. b. Appreciate the value of time by carrying out the experiment briskly and being on task all the time.

Scientific Concepts: Pressure in liquids a. acts in all direction b. increases with depth c. increases with density Materials, equipments and resource materials: Mineral water bottles – 4 units Oil – 1 bottle Tray – 2 units Plastic bag – 4 units Notes on PowerPoint slides Consideration of Safety Precautions: None

Prior Knowledge: Students have already learned the operational definition of pressure, P=F/A, and have applied it in solving problems involving pressure exerted by solids on a surface.

Teaching and Learning Activities Phase

Content

Introduction/ Eliciting Ideas (5 minutes)

Definition of pressure, P=F/A Direction of pressure in liquids and factors that might affect pressure in liquids Students experience whilst swimming (if any)

Structuring/ Pressure in Restructuring liquids of Ideas a. a. acts in all (15 minutes) direction b. is directly proportional to depth c. is directly proportional to density d. can be written as P=hρg

Teacher Activities

Student Activities

Notes

Make connection to students’ prior knowledge on pressure by asking questions Elicit students’ ideas about whether there is pressure in liquids, factors that might affect pressure in liquids and how these factors affect the pressure.

Students respond to teacher’s questions

Show a plastic bag full of water and ask students to predict which way the water will squirt out when holes are poked.

Students make prediction, inference, observation and conclusion

Strategy/Technique: Interactive demonstration by teacher

Students make hypotheses, give suggestions on the design of an experiment and state all the variables involved.

An inquiry activity in groups.

Strategy/Technique: Whole class Q&A

Ask two central guiding questions: How does pressure in liquid relate to depth? How does pressure in liquid relate to density? Ask students for their hypotheses, the design of an experiment to investigate the relationship, and the variables involved. Debriefing Guide students to construct the equation P=hρg from the two

Then students carry out the

relationships

activity to answer the central guiding questions. Students make conclusion and construct P=hρg

Application of Ideas (5 minutes)

1. The density of Show problems on fresh water is less slides than that of sea (refer to Appendix 1) water, the lower fresh water pressure is caused by its density 2. Two problem involving the use of P=hρg

Reflection/ Pressure in Closure liquids (5 minutes)e. a. acts in all direction b. is directly proportional to depth c. is directly proportional to density d. can be written as P=hρg

Let students conclude by stating the main ideas and relating to students initial ideas Show summary of main ideas on slides Give reading assignment on gas pressure for next lesson Written problem solving using P=hρg in exercise book

Students solve problems in groups

Strategy/Techniques Group discussion followed by group presentation

Students Resources: PP slides present their solutions

Students conclude the lesson by verbally stating the main ideas and relating to their initial ideas

Strategy/Techniques: Whole class Q&A Resources: PP slides