BuoyancyBuoyancyChapter 1: Lesson 2Chapter 1: Lesson 2

AimAim

Why did the Titanic Sink?Why did the Titanic Sink?

ObjectivesObjectives• Students will be able to define Students will be able to define

buoyancy.buoyancy.

• Students will be able to explain Students will be able to explain why some objects sink while why some objects sink while others float.others float.

• Students will be able to explain Students will be able to explain what happened to the Titanic what happened to the Titanic when it hit the iceberg.when it hit the iceberg.

BuoyancyBuoyancyWhy do some objects float, while other Why do some objects float, while other

objects sink?objects sink?

A coin sinks because it weighs more A coin sinks because it weighs more than the water it displaces.than the water it displaces.

The aluminum ball floats because it The aluminum ball floats because it contains air within its folds.contains air within its folds.

Air weighs less than water, so the ball Air weighs less than water, so the ball weighs less than the water it weighs less than the water it displaces.displaces.

BuoyancyBuoyancy• Archimedes was an ancient Greek Archimedes was an ancient Greek

scientist who discovered that scientist who discovered that floating objects are supported by an floating objects are supported by an upward force called upward force called buoyancybuoyancy. ( P.S.- . ( P.S.- he discovered this while taking a he discovered this while taking a bath, and decided to run through the bath, and decided to run through the streets shouting out “Eureka, streets shouting out “Eureka, Eureka!”)Eureka!”)

• Buoyant force is equal to the weight Buoyant force is equal to the weight of the liquid that the force displaces.of the liquid that the force displaces.

• The theory concerning buoyancy is The theory concerning buoyancy is called Archimedes Principle.called Archimedes Principle.

Why did the Why did the Titanic Sink?Titanic Sink?

• After it hit the iceberg, water began to After it hit the iceberg, water began to fill the air filled compartments on the fill the air filled compartments on the ship.ship.

• The added weight of the water, The added weight of the water, combined with the weight of the ship combined with the weight of the ship became greater than the buoyant force became greater than the buoyant force supporting the ship.supporting the ship.

• We all know what happened after that!We all know what happened after that!

Let’s go to the Video!Let’s go to the Video!

QuickTime™ and aSorenson Video 3 decompressorare needed to see this picture.

HWHW1.1. Answer chapter review Answer chapter review

questions on pages 9-12 questions on pages 9-12 on page 24.on page 24.

2.2. Read pages 7-10 (top of Read pages 7-10 (top of page).page).

3.3. Answer section review Answer section review questions 1-3 on page 10.questions 1-3 on page 10.