Unit: Physical Science

1. Unit: Physical Science Chapter 11: Matter and its Properties

2. What is Matter?

3. Elements All things around us are made with just a few kinds of matter. Each kind of matter has its own set of properties. • There are over100 basic kinds of matter called elements. • Elements are the basic building block of matter. • They combine to make up all other kinds of matter. • They cannot be broken into smaller pieces with ordinary physical or chemical processes. More than 75% of the elements are called metals. Metals are shiny, bendable, and able to conduct heat energy and electricity well.

4. Periodic Table of Elements This contains all of the known elements. Elements can be combined to make other things For example, hydrogen and oxygen combine to make water.

5. Element properties • Each element has its own set of chemical and physical properties • Chemical properties describe how a material changes into other materials • Physical properties can be measured without changing the material • Examples: color, odor, mass, volume, Density, texture, Magnetism and hardness. • These properties do not change.

6. Weight vs. mass Weight Mass • Weight- a measure of the pull of gravity on an object • Weight changes when the pull of gravity changes. • The pull of gravity is not the same everywhere on earth. If you were on mt. Everest you would weight less than you do right now. Why is that? • You would weigh more in New Orleans than you do right now. Why is that? • Use a spring scale (the spring is pulled to measure the pull of gravity) • Mass- the amount of matter in an object • The amount of matter affects the weight of the object, but mass is not the same as weight. • Mass never changes. • use a balance or digital scale • The units are normally listed in grams, milligrams, or kilograms.

7. Volume • Volume- the amount of space that an object takes up. • Cubic units are used for volume. • Ways to find volume • If you are finding the volume of a box, you can multiply the length, width, and height of the box together to get the volume. • V=lxwxh • If you have an odd shape, you can measure the volume with a graduated cylinder. • Measure the amount of water in the cylinder at the start, drop the object in the water and measure the new level. Subtract the two amounts and you will have the volume of the object.

8. Density • Density- the measure of the amount of matter in a given volume. • The density of an object will never change • You find density by dividing the object’s mass by its volume. • What is the density of an object whose mass is 15g and has a volume of 5? • Equal volumes of any two different substances usually have different masses. • This means that the two substances have different densities.

9. Buoyancy • An object is buoyant if it floats. • Whether a certain material floats in a liquid depends on the densities of both the material and of the liquid • If the object’s density is less than the density of the liquid, it will float. • If the object’s density is more than the density of the liquid, it will sink. • What objects on the table will float in water? • Note: ocean water has dissolved salt and other materials, this makes ocean water more dense than fresh water.