Performance Task Development Worksheet Class:Physics Unit:Scientific Inquiry Task Title:Surface Tension Thinking about the Standard: This task focuses on Scientific Inquiry, but also contains issues concerning problem solving and communication skills. S21: Identify testable questions and form hypotheses based on observations. S22: Design and conduct experiments to answer questions and verify hypotheses. S23: Analyze data collected from an investigation, draw conclusions and explain results. S24: Communicate and defend findings using scientific arguments. (M14,M15,M16,M17,L8, & L10) Thinking about the Context: Thinking about the Performance: standard Contextual applications using surface tension. Unique properties of water. Water Skiing Diving Surface Tension and Soap bubbles Teeter totters Demonstrate the ability to build device to adjust and test in order to look at a variety of variables. By adjusting the different variables (one at a time), the student will be able to demonstrate gains in understanding of surface tension and the forces involved in the behavior of the device itself. Data will be recorded in Tabular form product context performance Thinking about the Product: Thinking about the Scoring Criteria: Students will write a lab report “using as much math as possible”. Students will need to decide what information is important to include in the lab report itself, along with how best to organize the information in the report. Report should demonstrate conceptual understanding of the problem, show a variety of ways to solve problems, explain solutions to problems and explain thinking in written form. Content: Conceptual understanding of the problem. Processes & Strategies: Different ways to solve the problem. Interpret Results: Explain why solutions make sense. Communicates Effectively: Explain thinking in writing. (Scale of 1-6 on all 4 categories): 24 point total.

Surface Tension The cohesive forces between liquid molecules are responsible for the phenomenon known as surface tension. The molecules at the surface do not have other like molecules on all sides of them and consequently they cohere more strongly to those directly associated with them on the surface. This forms a surface "film" which makes it more difficult to move an object through the surface than to move it when it is completely submersed. Surface tension is typically measured in dynes/cm, the force in dynes required to break a film of length 1 cm. Equivalently, it can be stated as surface energy in ergs per square centimeter. Water at 20°C has a surface tension of 72.8 dynes/cm compared to 22.3 for ethyl alcohol and 465 for mercury.  

Surface Tension in contact with air - σ 10-2 (N/m) Surface Tension of Water in Contact with Air - SI units  Surface Tension of Water in Contact with Air - SI units  Temperature - t  (oC) Surface Tension in contact with air - σ   10-2 (N/m) 7.56 5 7.49 10 7.42 20 7.28 30 7.12 40 6.96 50 6.79 60 6.62 70 6.44 80 6.26 90 6.08 100 5.89 Temperature - t  (oC) Surface Tension in contact with air - σ   10-2 (N/m) 7.56 5 7.49 10 7.42 20 7.28 30 7.12 40 6.96 50 6.79 60 6.62 70 6.44 80 6.26 90 6.08 100 5.89 Temperature - t  (oC) Surface Tension in contact with air - σ   10-2 (N/m) 7.56 5 7.49 10 7.42 20 7.28 30 7.12 40 6.96 50 6.79 60 6.62 70 6.44 80 6.26 90 6.08 100 5.89

                                                   

R.P.Feynman The Character of the Physical Law [ There is a]   rhythm and pattern between the phenomena of nature which is not apparent to the eye, but only to the eye of analysis; and it is these rhythms and patterns which we call Physical Laws.                    R.P.Feynman           The Character of the Physical Law

Basic Skills of Scientific Inquiry ·        Observing ·        Classifying and sequencing ·        Communicating ·        Measuring ·        Predicting ·        Hypothesizing ·        Inferring ·        Defining, controlling, and manipulating variable in experimentation ·        Designing, constructing and interpreting models ·        Interpreting, analyzing and evaluating data

Linman's Thinking...

Scientific Inquiry: It is all about ATTITUDE !!! Reading Writing Listening Talking Feeling Theory Relative Structuring Using Principles Interpreting Hypothesizing Predicting Using Numbers Testing Comparing Using Verified Facts Classifying Using Variables Interacting Manipulating Variables Abstracting Generalizing Making Orderly Relations Recording Inferring Using Observed Facts Using Intuition Comparing Testing ID of Variables Guessing Questioning Finding Discrepancies Observing Perceiving Relevance Using numbers Problem Focus Experience Scientific Inquiry: It is all about ATTITUDE !!!

Let’s get some SKILLS out of the way……. And now Let’s get some SKILLS out of the way…….

Topics Simple Algebra/Dimensional Analysis Scientific Notation Precision vs. Accuracy The Myth Behind Significant Figures Math of Significant Figures Trigonometry Is your brain full yet????

Practice, Practice, Practice Algebra and Trig problems Precise and Accurate Sig Figs Over the next 48 hours see how much you can get done…..all of it????? Practice makes perfect.