Density

Objectives

• Students will have a basic understanding of density as it relates to floating or sinking.
• Students will explore the basics concepts of density and not actually calculate the density of the objects.

Kit Contents

• Red Program Folder

• Books (in kit)
  • Riley, Peter Floating and Sinking

• Equipment (in kit)
  • 1 Clear Plastic Box (pond)
  • 25 Chart Cards
  • 1 Laminated Sink or Float Chart
  • 1 Plastic Container with Lid
  • 1 Gold Key
  • 1 Large Button
  • 1 Small Button
  • 1 Package of Pebbles
  • 1 Tube
  • 1 Turtle
  • 1 Duckling
  • 1 Octopus
  • 1 Goldfish
  • 10 Frogs
  • 1 Shark
  • 1 Pink Murex Shell
  • 5 Sailboats
  • 1 Marble
  • 3 Cubes (Wood, Sponge, Metal)
  • 1 Airplane
  • 1 Pumice Stone
  • 1 Calcite Stone
  • 10 Pigs
  • 1 Log
  • 1 Cork

Lesson

• Introduction
  • Density is the mass or amount of matter in a substance.
  • Two objects can weigh the same, but have different densities. A pound of feathers weighs the same as a pound of bricks, but the bricks are much denser and take up less space, although both weigh the same.

• Program
  • The kit contains a variety of objects, some which sink and others, which float.
  • Have your student feel the objects and tell you some of the differences between the various objects.
  • Have students make a prediction as to which will float or sink in water. ( Be careful not to add commentary to what your student says. Even in the high school, it is not uncommon for students to believe that because color effects whether an object will sink or float.)
  • Fill the tub with water and have your student test the objects. Record which ones were able to float and which objects sank.
  • Work with your student to revise his/her ideas as to why an object floated or sank. Then using this new hypothesis collect other objects from around the house, which meet the specifications in the hypothesis and test it.
  • Take a container and fill it with 5 marbles. See how fast it sinks. Now take the same container and fill it with 10 marbles. Does it sink faster? With 15 marbles? Each time the container increases in density (more marbles) it sinks faster.
  • Conclusions
    • Density is a ratio of the object's mass compared to its volume – the quantity of the substance packed into a given space. Water has a density of one, meaning that its mass and volume are equal to each other. If an object's mass is greater than its volume, the density will be more than one and the object will sink. If an object's mass is less than its volume, the density will be less than one and it will float.

 

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