1. Grade 9 Science

2. What is the difference between a theory and a law??

3.  Descriptions of events or patterns  Does not involve an explanation

4. Explanations of observations supported by evidence Often change over time

6.  believed matter to be composed of: ◦ earth, ◦ air, ◦ fire, ◦ and water  All matter is made of tiny particles called atoms

8. State the 4 points of Daltons Atomic Theory:  1  2  3  4  Use page 26 of the text

10.  Atoms composed of small particles  Atoms contain negatively charged particles called electrons  Raisin bun model

13.  Probed inside the atom  Exposed gold to a stream of heavy positively charged particles  Realized large space within atoms  Discovered the nucleus of the atom  Established that the nucleus had 2 types of particles: proton (+) and neutron (0)

15.  Studied the area around the nucleus  Area around nucleus contained electrons (-)  Studied light emitted by gas  Proposed electrons surround nucleus in specific energy levels  Electrons contain specific amounts of energy

19.  Page 33  #1,3,5,6,11