3/3 & 3/4 - 8th Grade Agenda Learning Objective: Learn about Density Collect HW: Reading & Notetaking p.192 – 194 Textbook Reading p. 425 - 429 HW: Reading & Notetaking p.195 – 196
Daily Reflection Prompt: Write 3 questions that you have about “density”.
What is Density?
Comparing Densities
Why do objects float? Because the pressure at the bottom of a submerged object is greater than the pressure at the top
Why does objects feel lighter in water than in air? Buoyancy Force
Submarine
Why do some objects float while others sink?
Archimedes 287-212 BC King Hieron suspected that the gold crown that he received from his gold smith was not of pure gold He asked Archimedes to investigate and prove his findings
How did Archimedes solved the problem? He knew Gold and Silver weighed different amounts If he knew the volume of the crown then he can compare it’s weight against the weight of equal amount of gold and silver How can you find a volume of crown?
How did Archimedes solved the problem? While taking a bath, he realized that the water that ran over equaled in volume the submerged part of his body He now knew the volume of the crown and by weighing it he proved that it was not made of pure gold.
Archimedes’ Principle
Pascal’s Principle When force is applied to a confined fluid, the change in pressure is transmitted equally to all parts of the fluid
Hydraulic Device
Hydraulic Brakes