+ Properties of Liquids & Gases Explained by the particle model of matter.

+ Key Concepts Properties of fluids Mass, volume, density Viscosity and flow rate Buoyancy

+ Learning Objective: Define viscosity and describe how temperature effects it.

+ Remember… Liquids are fluids, but gasses are also fluids! Think of a fluid as any matter that has no fixed shape- it takes the shape of its container.

+ How quickly fluids flow…. Is a property called viscosity. What fluids didn’t flow the way they usually do?

+ Viscosity… Is determined by a fluids internal resistance or friction that keeps it from flowing.

+ Fluids with high viscosity… Do not flow as easily as fluids with low viscosity.

+ Temperature can have a big effect on viscosity.

+ The Ramp Test The ramp method of testing viscosity involves pouring a fluid down a ramp and timing how long it takes to get to the bottom. By pouring the same amount of another liquid and timing it, you can compare the viscosities of different fluids.

+ Temperature Test the same fluid at different temperatures: Room Temperature Warmed in Hot Water Cooled in an Ice Bath

+ How Fast Can It Go? You will use the ramp test to determine the effect of temperature on the viscosity of four fluids. Design a fair test that will allow you to collect evidence to demonstrate the effect of temperature on viscosity. Write a procedure and show it to me for approval. Then carry out your tests. When you have completed your tests, create a one-page summary poster of your results. Include one graphic illustrating your results.

+ Caution! Handle hot water carefully- ZERO fooling around. Materials and Equipment Shampoo Pancake Syrup Vegetable Oil Teflon-coated cookie sheet Thermometer Hot water Cold water Beakers Phone (to use as a stopwatch)

+ Experiments (1) Ask a cause-and effect- question: How does the concentration of laundry detergent in wash water affect the cleanliness of clothing?

+ (2) Restate the question in the form of a hypothesis: If the concentration of the detergent is high, then the clothing will become cleaner.

+ (3) Develop a procedure to test the hypothesis fairly. Some questions you should think about: Which manipulated variable do you want to investigate (what are you going to change? What are you going to keep constant?) How will you measure this variable? How will you keep all other variables constant (the same) so they won’t affect your results? In other words, how will you control your experiment so it is a fair test?

+ (3) Develop a procedure to test the hypothesis fairly. Some questions you should think about: What materials will you need for the experiment? How will you conduct the experiment safely? How will you record the data that you collect?

+ (4) Carry out the procedure and collect the data. Are you going to use a chart/table/sketches/notes? Or maybe a combination?

+ (5) Analyze and interpret the data. Look for patterns and relationships in your data.

+ (6) Form conclusions Does your data support your hypothesis? Experiments must be conducted over and over again to prove a hypothesis.

+ (7) Communicate the procedure and results of your experiment. Your poster! Summarize your first 6 steps (your experiment) Drawings? Charts? Graphs?