Grade 9 Science
What is the difference between a theory and a law??
Descriptions of events or patterns Does not involve an explanation
Explanations of observations supported by evidence Often change over time
believed matter to be composed of: ◦ earth, ◦ air, ◦ fire, ◦ and water All matter is made of tiny particles called atoms
State the 4 points of Daltons Atomic Theory: 1 2 3 4 Use page 26 of the text
Atoms composed of small particles Atoms contain negatively charged particles called electrons Raisin bun model
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)
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
Page 33 #1,3,5,6,11