Or

Author:
Jack Bauer

1.Of the objects below, circle the ones you think would float in water. If you cannot circle them on your computer, simply type the names here:

2.Why do some objects float, while others sink

Gizmo Warm-up

The Density Laboratory Gizmo™ allows you to measure a variety of objects, then drop them in water (or other liquid) to see if they sink or float.

1. An object’s mass is the amount of matter it contains. The mass of an object can be measured with a calibrated scale like the one shown in the Gizmo. Drag the first object onto the Scale. (This is object 1.)

What is the mass of object 1?

2.An object’s volume is the amount of space it takes up. The volume of an irregular object can be measured by how much water it displaces in a graduated cylinder. Place object 1 into the Graduated Cylinder.

What is the volume of object 1?

3.Drag object 1 into the Beaker of Liquid. Does it sink or float?

Question: How can you predict whether an object will float or sink?

1.Observe: Experiment with the different objects in the Gizmo. Try to determine what the floating objects have in common and what the sinking objects have in common.

2.Form hypothesis: Compare the floating objects, then do the same for the sinking objects.

A.What do the floating objects have in common?

A.What do the sinking objects have in common?

3.Collect data: Measure the mass and volume of objects 1 through 12, and record whether they float or sink in the table below. Leave the last column blank for now.

4.Analyze: Look carefully for patterns in your data.

A.Does mass alone determine whether an object will float or sink?

B.Does volume alone determine whether an object will float or sink?

C.Compare the mass and volume of each object. What is true of the mass and volume of all the floating objects?

D.What is true of the mass and volume of all the sinking objects?

5.Calculate: The density of an object is its mass per unit of volume. Dense objects feel very heavy for their size, while objects with low density feel very light for their size.

To calculate an object’s density, divide its mass by its volume. If mass is measured in grams and volume in cubic centimeters, the unit of density is grams per cubic centimeter (g/cm3).

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