Midterm Exam Study Guide - Science

Midterm Exam - Study Guide

• This guide covers lessons included in the midterm exam, including the scientific method, matter, changes of state, properties of matter, atoms, the periodic table, ions, electric charge, electric current, and electric circuits.

Lesson 1: Scientific Method

• Definition: A process used to find answers to questions about the world.
• Steps:
  • Identify the problem
  • Form a hypothesis (educated guess)
  • Design an experiment
  • Conduct the experiment
  • Analyze the data
  • Communicate the results
• Variables:
  • Independent variable: What is changed in the experiment.
  • Dependent variable: What is measured in the experiment.
  • Controlled variable: What remains constant.
• Control group: The group that does not receive treatment.
• Experimental group: The group that receives treatment.

Lesson 2: Matter

• Definition: Anything that has mass and takes up space.
• States of Matter: Solid, Liquid, Gas.
• Properties of Solids, Liquids, and Gases:
  • Solids: Particles tightly packed, fixed shape, definite volume, cannot be compressed.
  • Liquids: Particles further apart, indefinite shape, fixed volume, can be compressed.
  • Gases: Particles very far apart, indefinite shape, indefinite volume, easily compressed.

Lesson 3: Changing States of Matter

• Changing states requires energy.
• Processes: Melting, freezing, vaporization, condensation, sublimation, and deposition.
• Melting: Solid to liquid (heat added)
• Freezing: Liquid to solid (heat released)
• Vaporization: Liquid to gas (heat added)
• Condensation: Gas to liquid (heat released)
• Sublimation: Solid to gas (heat added)
• Deposition: Gas to solid (heat released)

Lesson 4: Physical and Chemical Properties of Matter

• Physical properties: Properties that can be observed or measured without changing the identity of the substance. (e.g., color, density, melting point).
• Chemical properties: Properties that describe how a substance reacts with other substances to form new substances (e.g., flammability, reactivity).
• Physical changes: Changes that affect physical properties but do not change the substance's identity (e.g., cutting, melting).
• Chemical changes: Changes that result in the formation of new substances (e.g., burning, rusting).

Lesson 5: Atoms

• Definition: The smallest unit of an element that retains its chemical properties.
• Subatomic Particles: Protons (positive charge), neutrons (neutral charge), and electrons (negative charge).
• Atomic number: Number of protons in an atom.
• Mass number: Number of protons plus neutrons in an atom.

Lesson 6: The Periodic Table: Metals & Non-Metals

• Organization: Elements are arranged by increasing atomic number (number of protons), reflecting recurring chemical properties.
• Periods: Horizontal rows on the periodic table.
• Groups: Vertical columns on the periodic table.
• Metals: Found on the left side of the periodic table, typically shiny, malleable, ductile, good conductors of heat and electricity.
• Nonmetals: Found on the right side of the periodic table, often brittle, poor conductors of heat and electricity.
• Metalloids: Have properties of both metals and nonmetals, found along the dividing line (zigzag line) on the periodic table.

Lesson 7: Ions

• Definition: An atom that has gained or lost one or more electrons, resulting in a net electric charge.
• Cations: Positively charged ions (formed by losing electrons).
• Anions: Negatively charged ions (formed by gaining electrons).
• Calculating total charge: In a neutral atom, the number of protons equals the number of electrons (total charge = 0).

Lesson 8: Electric Charge and Static Electricity

• Electric force: Force between charged objects.
• Types of charges: Positive and negative.
• Charging methods: Friction, conduction, and induction.
• Static electricity: The buildup of electric charge on an object.
• Static discharge: The release of static electricity.

Lesson 9: Electric Current

• Definition: The rate of flow of electric charges.
• Unit: Ampere (amp).
• Conductors: Materials that allow electric current to flow easily.
• Insulators: Materials that do not allow electric current to flow easily.
• Factors affecting current: Voltage, resistance.

Lesson 10: Electric Circuits

• Definition: A closed path through which electric charges can flow.
• Components: Energy source (battery), conductors (wires), load (device that uses electricity), switch(controls the circuit).
• Types of circuits: Series and parallel.
• Series circuits: A single path for electricity to flow through.
• Parallel circuits: Multiple paths for electricity to flow through (voltage is the same for each load).
• Safety Devices: Fuses, circuit breakers.
• Short circuits: Abnormal connections causing circuit damage, often due to overheating or fire. I