Chapter 1-2 Measuring Matter

How do you find your weight on Earth? You use a scale Your body weight presses down on the springs inside the scale. The more you weigh, the more the springs compress, causing the pointer on the scale to turn farther, giving a higher reading. Weight would less on moon because the springs would not compress as much

Mass The mass of an object is the measurement of the amount of matter in the object. Mass does not change with location

Units of Mass Use metric or SI system (International System of Units) The SI unit of mass is the kilogram (kg). Measured with triple beam balance Ex: If you weigh 90 pounds on Earth, your mass is about 40 kilograms.

Weight Your weight is a measure of the force of gravity on you. All objects are attracted toward the center of the planet by the force of Earth’s gravity. You would weigh only about one-sixth of your weight when your are on the moon Earth. Measured in Newtons

Volume The amount of space that matter occupies is called its volume.

Calculating Volume of a Liquid Use graduated cylinder Measured in milliliters(mL) or liters (L) Ex: typical soda bottle is one liter Ex: One teaspoon of water is about 5 mL

Calculating Volume of a Solid Use cubic centimeters (cm 3 ) to measure solid objects Volume =Length x width x height

Volume of irregular object Use graduated cylinder to measure the volume of an irregular object by seeing how much the water level rises when the object is submerged.

Density Density relates the mass of a material in a given volume Often expressed as grams per cubic centimeter (g/cm 3 ) You can determine the density of a sample of matter by dividing its mass by its volume.

Sinking or floating? The density of water is 1 g/cm 3. Objects with densities greater than that of water will sink. Objects with lesser densities will float. Ex: the density of this wood is less than 1 g/cm 3, so it will float the density of the iron is greater than 1 g/cm 3, so it will sink

Using Density Can be used to identify an unknown substance. Ex: You can determine if a gold colored rock is gold by measuring the mass and volume of the rock to determine density.