Science End-Term Review Weeks 1-10

Science End-Term Review

• The review covers weeks 1-10 of science.
• Topics include The Scientific Method & Fair Testing, Atoms and Elements 1 & 2, Introduction to Respiration, Plants: Germination and Growth, Plants: Transpiration and Transport of Nutrients, and Acids and Alkalis.
• Personal protective equipment (PPE) is a critical aspect of lab safety.
• PPE includes safety goggles, mask, earplugs/hearing protection, safety gloves, closed-toe shoes, hair net/helmet, and lab coat.

Lab Safety

• Highly Flammable substances easily catch fire, shown by a diamond-shaped symbol with a flame.
• Corrosive substances attack and destroy living tissues, signified by a diamond-shaped symbol with a beaker and damage symbol.
• Toxic substances cause death by ingestion, inhalation, or absorption through skin, symbolized by a diamond-shaped symbol with a skull and crossbones.

The Scientific Method

• The scientific method solves problems and questions.
• The steps involve observation, hypothesis, prediction, experiment, and data analysis.

Fair Testing

• Fair testing involves changing only one variable while keeping all other variables consistent.
• Three types of variables in fair testing are: independent, dependent, and control.
• In a fair test, the dependent variable depends on the independent variable. One independent variable is changed at a time, while the others are controlled.

Atoms and Elements

• An element is a substance made of only one type of atom.
• Examples include carbon, copper, and helium.
• A compound is a substance formed when two or more chemical elements are chemically bonded together.
• Elements within compounds are always in fixed ratios.
• Compounds can only be broken down into their constituent elements using chemical reactions.
• Examples of compounds are H₂O (water), CH₄ (methane), NaCl (salt), and C₆H₁₂O₆ (glucose/sugar).
• Metals are typically on the left side of the periodic table.
• Non-metals are usually found on the right side of the periodic table.
• Metalloids are positioned between the metals and non-metals.

Common Elements

• Atomic symbols and atomic weights (or masses) are relevant for identifying elements.
• Specific data is included for Helium, Hydrogen, Potassium, Chlorine, Magnesium, Aluminum, Gold, Argon.

The Periodic Table

• The periodic table is organized by horizontal rows (periods) and vertical columns (groups).
• Periods have the same number of electron shells.
• Groups share similar chemical and physical properties, dictated by the number of valence electrons.

Shell Models

• The number of shells and valence electrons determine the group and period of an element in the periodic table.
• Elements in the same group exhibit similar chemical properties.
• Magnesium has 3 electron shells and 2 valence electrons. Hydrogen (H), Fluorine (F), and Argon (Ar) have 1 electron shell, 2 electron shells, and 3 electron shells, respectively, illustrating how to determine the period and group.

Physical Properties

• Physical properties are observable characteristics of substances without changing their chemistry.
• Examples include color, freezing/boiling points, density, and smell.

Chemical Properties

• Chemical properties describe how a substance changes in composition or structure when interacting with other substances.
• Examples include flammability, chemical stability, reactivity, and toxicity.

Introduction to Respiration

• Breathing in (inhalation) involves intercostal muscles contracting to expand the chest wall, and the diaphragm contracting and moving down, causing the lungs to increase in size, drawing air in.
• Breathing out (exhalation) involves intercostal muscles relaxing to decrease the chest size, the diaphragm relaxing and bulging up, causing the lungs to decrease in size, expelling air.

Plants: Germination and Growth

• Germination factors include water needed to activate enzymes that use oxygen and stored food for making energy through respiration. Oxygen is critical for seeds to start making energy. The optimal temperature for germination varies among plants. Seeds need a certain level of soil warmth.
• Six Key Steps of Germination and Growth (includes images):
  1. Seed absorbs water from soil.
  2. Embryo breaks through seed coat.
  3. Embryo sends root down into soil.
  4. Shoot grows up above soil.
  5. Seedling begins to grow leaves.
  6. Seedling grows into mature plant.

Plants: Transpiration and Transport of Nutrients

• The xylem transports water and minerals in one direction.
• The phloem transports glucose in either direction.
• Water moves up a plant via osmosis and capillary action (adhesion and cohesion).

Plant Nutrients

• Plants require essential minerals for chemical reactions to survive.
• Several essential minerals are depicted in an image.
• Nitrogen (N), phosphorus (P), potassium (K), and magnesium (Mg) are critical for healthy plant growth and development. Specific functions of each are shown.

Fertilizers

• Fertilizers contain nutrients aiding plant growth.
• They increase crop yield by providing essential minerals.

Water and Mineral Transport

• Three steps of water/mineral movement up a plant are: Osmosis, Capillary Action (adhesion/cohesion), and Transpiration
• Step 1 (Osmosis): Water and dissolved nutrients enter the root hairs and grow into plant roots from the soil.
• Step 2 (Capillary Action): Adhesion (water sticking to other materials, like xylem vessels); cohesion (water molecules sticking to other water molecules). Water is drawn up through the plant's xylem vessels by capillary action.
• Step 3 (Transpiration): Water evaporates from leaf pores (stomata), creating a pressure pull that draws more water up the plant.

Acids & Alkalis

• The pH scale measures acidity and alkalinity, ranging from 0-14, with 7 being neutral.
• The pH scale ranges from 0 to 14, with 0 being most acidic, 14 being most alkaline, and 7 being neutral.
• Various substances (e.g., battery acid, lemon juice, milk, blood, baking soda, and drain cleaner) are listed with their corresponding pH values.

This quiz covers key topics from the first ten weeks of science, including the Scientific Method, Atoms and Elements, Respiration, and plant growth processes. Important safety practices in the lab, particularly regarding personal protective equipment and the handling of hazardous substances, are also highlighted. Prepare for your end-term examination with this comprehensive review.