Monday, March 20th Entry Task No new entry task brochure today. Schedule: 12.1 & 12.2 Quiz Pressure notes Objective: I can describe how pressure depends on force and area Homework: 12.3 RSG Please have on desk: ISN open to Friction graphic organizer and activity Last week’s entry tasks

Pressure depends on area The amount of pressure we feel depends on how much force is applied over how much area P = F/A

Pressure acts in all fluids Liquids and gases exert pressure in all directions on the things around them. Why don’t we notice that the air around us is pressing on us? Free template from www.brainybetty.com

Pressure acts in all fluids For every action force, there is an equal and opposite reaction force. Air pushes on us, we push on air with an equal, but opposite force. (Newton was brilliant!)

Pressure acts in all fluids Ears hurt when pressure outside is greater than pressure inside. Ears hurt when pressure inside is greater than pressure outside 1/28/2018 Free template from www.brainybetty.com

Pressure acts in all fluids Air Pressure decreases as you climb higher in the atmosphere As you climb less air is above you. Less Force = Less Pressure

Pressure acts in all fluids Water Pressure increases as you dive deeper More water is above you, so it exerts a greater Force on a given Area. More Force = More Pressure

What is the purpose of wearing snow shoes?

Possible Answer The lady wants to spread her force out over a larger area of the snow so she stays on top of it. If she did not have snowshoes, she might “sink” into the snow. If her force is spread out, there is not enough pressure on any one spot to “sink” .

Why doesn’t the person on the bed of nails get pierced by them?

Possible answer The force of the nails on the person’s body is spread out over the area of his entire body. No one nail has enough pressure to pierce the skin.

Tuesday, March 21st Entry Task Explain why your ears hurt when you dive deep into a swimming pool. Schedule: Bill Nye Pressure Pressure Math Objective: I can calculate pressure, force, or area when provided 2 of the quantities using the formula P = F/A Homework: Complete the pressure math worksheet

Wednesday, March 22nd Entry Task A box with weight of 25 N is placed on a brick with an area of 0.12 m2. How much pressure does the box exert on the brick? Schedule: 12.3 quiz Gravity, friction, and pressure review Objective: I will review 12.1, 12.2, and 12.3 Homework: Finish review if not completed in class Please have on desk: ISN open to pressure math worksheet

Thursday, March 23rd Entry Task Draw a picture of a balloon and draw arrows to show the pressure on it. Schedule: Buoyancy notes Objective: I can explain how fluids exert forces Homework: Output page (questions 1-6, page 407) IQIA!!! What happens when you don’t understand buoyancy? Please have on desk: ISN open to yesterday’s review

Fluids exert an upward force on objects Fluids (liquids and gases) push in all direction on things in them…including pushing them up. Free template from www.brainybetty.com

Fluids exert an upward force on objects The upward force of fluids is called Buoyant Force Gravity and Buoyant Force oppose each other

Fluids exert an upward force on objects If gravity is much stronger than buoyant force, the object will _________. If buoyant force is much stronger than gravity the object will __________ If the 2 forces are equal, the object will ___________________________. sink float Neither sink nor float, but stay in one spot

Fluids exert an upward force on objects Density and buoyant force are related. The more dense the fluid, the greater buoyant force it has. Salt water is more dense than fresh water More dense = more buoyant force = easier to float

Fluids exert an upward force on objects Density and buoyant force are related. The more dense the object in the fluid, the less buoyant force affects it. More dense stuff sinks, less dense stuff floats

Air has buoyant force too Air has buoyant force too. The buoyant force of colder, more dense air is able to push the warmer, less dense air in the balloon upwards.

Fluids exert an upward force on objects Buoyant force changes weight Buoyant force opposes gravity so the object will weigh less with additional buoyant force Astronauts train in water to get used working in space

Buoyancy and The Titanic The 2 forces that are balanced in floating ships are Gravity and Buoyant force. The overall density of the Titanic was less than the density of water because it was filled with air. After it hit the iceberg, the density of the Titanic increased because the air compartments in the front of the ship filled with water.

To summarize: buoyant force is the upward force on objects in a fluid is why ice floats in water is why objects seem lighter in water buoyant forces on an object are equal to the weight of the water that is displaced by the object if an object is more dense than the fluid then it will sink. if an object is less dense than the fluid then it will float.

Motion of fluid affects pressure Bernoulli’s principle An increase in the speed of the motion of a fluid decreases the pressure within the fluid The faster a fluid moves, the less pressure it exerts on the surfaces of openings it flows over. Chimney, air plane, race car and prairie dog examples

Forces transmitted through fluids Pascal’s Principle When an outside pressure is applied at any point to a fluid in a container, that pressure is transmitted throughout the fluid with equal strength. Examples: pressing on a tube of toothpaste, hydraulics

Friday, March 24th Schedule: Buoyancy activity Objective: Entry Task Why does toothpaste come out of the tube when you squeeze it? Schedule: Buoyancy activity Objective: I will obtain and graph buoyancy data for different objects and fluids Homework Complete buoyancy activity Please have on desk: Journal open to buoyancy notes