 As you watch the Bill Nye video, complete the following: › Write a definition for “buoyancy” › Write 2 things you already knew about buoyancy › Write 2 interesting facts you learned about buoyancy Bill Nye - Buoyancy

 When an object is placed in a fluid, the fluid presses on the object in all directions.  The force that presses upwards is known as buoyancy.  Buoyancy is related to an object’s density.  Buoyancy determines whether an object sinks or floats.  Buoyancy – The upward force that a fluid exerts on an object.

1. Using a spring scale, weigh a lump of modelling clay (weight in air). 2. Submerge the clay into a container of water, and record its weight (weight in water) › What do you notice about the weight in air and weight in water? What might the different between these two values represent? What is the buoyant force acting on the clay? 3. Modify the shape of the lump of clay until it floats. Measure the weight in air. › What do you notice about the weight? 4. Add marbles, one at a time, until the clay shape is one marble away from sinking. Record the mass. StructureMass in AirMass in WaterDifference Ball Boat

 Questions to think about Can you think of a relationship between the volume (displacement) of the clay and buoyancy? 2. Can you think of a relationship between the density of the clay and buoyancy?  Hint: Think of the formula for calculating density: Density = Mass / Volume

 2 objects with the same mass can sink or float depending on different factors.  Think of the formula D = m/v. The greater the volume (displacement), the lower the density. An object with a low density will be more buoyant (higher buoyant force).  By increasing the ship’s volume with air masses and shape, you increase its volume and displacement.  Floating objects have equal buoyant force and force of gravity. Cardboard Boat Man Cardboard Boat Man Titanic & Buoyancy Titanic & Buoyancy

 Explanation through a Hollywood Short starring Brad Pitt, Harrison Ford and Christian Bale: › The Archimedes and Eureka Story The Archimedes and Eureka Story  Archimedes Principle: “ Any object, wholly or partially immersed in a fluid, is pushed up by a force equal to the weight of the fluid displaced by the object.”  Try acting out the development of this principle through role play.

 All fluids, whether liquids or gases, exert an upward buoyant force on objects.  The buoyant force that water exerts on an object is equal to the weight of the water the object displaces.  Substances and objects that are... › less dense than the fluid exhibit positive buoyancy (they float). › More dense than the fluid exhibit negative buoyancy (they sink). › Equal in density to the fluid exhibit neutral buoyancy (remain suspended in the fluid).

 Density & Buoyancy Review: › Density & Buoyancy Video Density & Buoyancy Video  Review the challenge and materials needed: › Penny Boat Challenge Penny Boat Challenge

Sebs Volume: 9ml Density: 0.26g/ml # of Pennies: 0 Group 1 Volume: 210ml Density: 0.012g/ml # of Pennies: 55 Group 2 Volume: 182ml Density: 0.014g/ml # of Pennies: 54 Group 3 Volume: 310ml Density: 0.008g/ml # of Pennies: 122 Group 4 Volume: 237ml Density: 0.012g/ml # of Pennies: 93 Group 5 Volume: 120ml Density: 0.023g/ml # of Pennies: 53 Group 6 Volume: 200ml Density: 0.015g/ml # of Pennies: 53 Group 7 Volume: 230ml Density: 0.011g/ml # of Pennies: 76 Group 8 Volume: 50ml Density: 0.14g/ml # of Pennies: 48

Sebs Volume: 9ml Density: 0.26g/ml # of Pennies: 0 Group 1 Volume: 100ml Density: 0.035g/ml # of Pennies: 17 Group 2 Volume: 357ml Density: 0.008g/ml # of Pennies: 97 Group 3 Volume: 26ml Density: 0.45g/ml # of Pennies: 9 Group 4 Volume: 170ml Density: 0.017g/ml # of Pennies: 53 Group 5 Volume: 416ml Density: 0.007g/ml # of Pennies: 96 Group 6 Volume: 369ml Density: 0.007g/ml # of Pennies: 99 Group 7 Volume: 135ml Density: 0.02g/ml # of Pennies: 37 Group 8 Volume: 172ml Density: 0.01g/ml # of Pennies: 50

 Read over lab assignment: › Bubbling Lava Lamp Lab Bubbling Lava Lamp Lab  Introductory Video: › Steve Spangler Science: Steve Spangler Science: Bubbling Lava Lamp  Come prepared: › Clean plastic bottle or jar with its cap (tight lid is important!) › Bottle of vegetable oil (cheaper the better) › Observation table › Hypothesis for each of the 3 phases (part of your observation table)

Experiment Phase HypothesisObservations Pouring water and oil into the container? Dropping the tablet into the mixture? Tipping the bottle back and forth?