# Chapter 9 Science notes

```Chapter 9
Comparing Kinds of Matter
Lesson 1 Properties of Matter
• Mass-the amount of matter in an object; measured on a
pan balance; measured in kilograms or grams.
• Weight-how strongly gravity pulls on an object;
measured in pounds.
• Volume-measures how much space matter takes up; a
marble’s volume makes the water level rise when you
place it in a graduated cylinder.
Lesson 1 continued…
• Matter-anything that has mass and volume
• Density-the amount of mass for each mL (or cm&sup3;) of a
substance; as you add more marbles to a large box, you
are increasing the box’s density
Density=mass/volume
If a material is dense, matter is packed closely together.
Lesson 1 continued…
Buoyancy- the resistance to sinking
 Depends on density
 If you change the mass or volume of an object, you can change
whether or not it will float
 If you have a toy boat and keep adding mass to it, it will sink
Think of a buoy in the water!
Lesson 2 Elements
• Element-a material that cannot be broken down into anything
simpler by chemical reactions.
• 3 important properties of elements
1.
2.
3.
•
•
State of matter at room temperature
The way they combine with other elements
Whether they are metals, nonmetals, or metalloids
Most elements are solid at room temperature
Metals-elements that share common properties like shiny
luster, conductivity, and flexibility
Wood is not a good conductor of
electricity, but copper is!
See the shiny luster!
Lesson 2 continued
Look at the variety of colors!
Each color represents solids,
liquids, or gases (metals,
non-metals, or metalloids). To
See an up close version p. 494
in your textbook has a great example!
Lesson 2 continued…
• Atom- the smallest unit of an element that keeps
the properties of that element.
• Nucleus-the hard core/center of an atom; made
up of protons and neutrons.
Lesson 2 continued…
• Proton- a particle with one unit positive charge; the
number of protons in an atom is called the atomic
number and determines which element it is.
• Neutron- a particle with no electric charge; it is neutral
• Electron- smaller particle with one unit of negative
electric charge each; electrons move around in the space
outside the nucleus.
Lesson 2 continued…
• Molecule- particle with more than one atom joined
together.
• Elements are grouped together by their properties in the
periodic table
• On Earth, the most common elements by far are
hydrogen and helium
Helium
Lesson 3 Metals, Nonmetals, and
Metalloids
• Malleability- the ability to be bent, flattened, or
hammered without breaking
• Ductility- the ability to be pulled into thin wires without
breaking.
Gold is both malleable and ductile.
Copper is often drawn into wires for conducting
electricity.
Lesson 3 continued…
• Corrosion-when metals combine with nonmetals
from the environment.
Iron “corrodes” by
rusting, which causes the
corroded iron to flake
away.
Lesson 3 continued…
• One of the most resourceful metals we use today is
aluminum:
Often used in mirrors because it is inexpensive and can be
polished to be reflective.
Aluminum foil wrapped around food will trap heat inside
by reflecting it.
Can be used to conduct energy cheaply; it is used in
electrical wiring, water heaters, and radiators.
Easily coated with a thin layer of oxygen to help prevent
corrosion.
```