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Discover the fundamentals of mass, volume, and density through hands-on experiments with balloons, liquids, and solids. Learn how to calculate density, identify substances, and understand buoyancy principles. Explore Archimedes' Principle and real-life applications.
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Matter is anything that has mass and volume.1. Mass is the amount of matter an object has.2.Volumeis the amount of space an object takes up. • Question: Will an inflated balloon weigh more, less, or the same as the same balloon deflated? • Make a hypothesis, then test it. • Obtain the mass of a balloon, then inflate it, and then obtain the new mass.
Amount of matter Use a balance Kg Doesn’t change with location Pull of gravity Use a scale Newton Does change with location Mass vs. Weight
Which has more mass?A) 1 kilogram of feathersB) 1 kilogram of bricks They are the same! 1 kg = 1 kg
Which takes up more space?A) 1 kilogram of feathersB) 1 kilogram of bricks The Feathers
Measure matter by finding the density! Which has the greater density?A) steel bar B) steel paper clip The density of steel is the same! Size doesn’t matter!
Density of Steel steel bar
Units for Density Metric Units: Solid: g/cm3 Liquid: g/mL Density of water is 1g/mL(at 4º C) Memorize This!
Which one floats? Why? • Density of Water: 1.00 g/mL • Density of Ice: 0.92 g/mL Ice! Because it is less dense.
Which of the following will float on water?Why is it good to know the density? Density helps you identify a substance All those less than 1.0 g/mL
Predict the correct “floating order” of the substances as they would appear in the “Density Column”.
Calculating Density • Obtain mass using a balance. • Obtain volume by any of these methods. • Ruler: Volume = L x W x H • Graduated cylinder: water displacement D = m/vm = D x vv = m/D m “Magic Triangle” D v
Is the bar really gold or fool’s gold?Find the density of the bar if the mass is 1891.4 g and the dimensions are 3.5 cm by 3.5 cm by 8.0 cm. • Gold has a density of 19.3 g/cm3 V = L x W x H D = m/v 1891.4 g / 98 cm3 = 19.3 g/cm3 Yes it’s gold! m D v
Is this liquid water, alcohol, or kerosene? Find the density of the liquid if the mass is 16.98 g? Water 1.0 g/mLAlcohol 0.79 g/mLKerosene 0.82 g/mL • Read the volume D = m/v 16.98 g / 21.5 mL = 0.79 g/mL It is alcohol! m D v
Is the “Silver Surfer” really made of silver? We obtained a sample with a mass of 262.5 g. Platinum 21.5 g/cm3Silver 10.5 g/cm3Tin 7.3 g/cm3 Find the volume by water displacement. D = m/v = 262.5 g / 25 cm3 = 10.5 g/cm3 It is Silver! m d v
What is the volume in mL of this syrup if it has a density of 0.63 g/mL and a mass of 78 g? v = m/D = 78g ÷ 0.63 g/mL = 123.8 mL m D v
What is the mass in grams of this lead pipe if it has a density of 11.4 g/cm3 and a volume of 55 cm3? m = D x v = 11.4 g/cm3 x 55 cm3 = 627 g m D v
Buoyancy is the tendency for a less dense substance to float in a more dense substance. Boats are made so that they have a lower density than water. video
Buoyant Force The upward force exerted on an object immersed in a fluid is called the “buoyant force”. Click on picture for demo.
Draw a vector to show the buoyant force (up) and the weight force (down). Weight Force (Gravity) Which liquid exerts a greater buoyant force on the block? Blue or Clear? Buoyant Force Blue (greater)
Sink Weight Force > Buoyant Force Density of object > density of fluid Float Weight Force < Buoyant Force Density of object < density of fluid When will an object sink or float? (greater than) (less than)
Archimedes Principle • The buoyant force exerted on an object in a fluid is equalto the weight of the fluid displaced by the object. It explains: • the buoyancy of ships • therise of a balloon in the air • the loss of weight of objects underwater. Sink of Float buoyancy.html 2 N 2 N
Archimedes’ Principle Practice: • Rock weighs 2.25 N • In water, the rock weighs 1.8 N • The water displaced by the rock: • 2.25N – 1.8 N = 0.45 N. • So, the buoyant force exerted on the rock is 0.45 N. 0.45 N
Do all fluids exert the same buoyant force on an object? NO 0.45 N 0.53 N 2.25 N Which liquid exerts a greater buoyant force? Mercury
Buoyancy and GasesWhy do hot air balloons float? • A balloon will float when the weight of the balloon is less than the weight of the volume of air displaced. • Air in the balloon is heated to make it less dense than the surrounding air.
The beach ball and the basketball each contain the same amount of air. • Which has the greater amount of pressure and why? The basketball has greater pressure than the beach ball because it has less volume causing the air particles to have less space.
