Scientific Method
A hypothesis is best described as:
B. A possible answer to a scientific question.
What is the center of an atom called?
Nucleus
What is a pure substance made of one type of atom called?
Element
What are the three states of water?
Solid, liquid, and gas
What is condensation?
Condensation is the process by which water vapor (a gas) cools and changes into liquid water.
The process of using observations and evidence to draw conclusions is called:
A. Inference
What is the smallest particle of an element?
Atom
What does the subscript 2 in H₂O represent?
There are two hydrogen atoms in a water molecule
What property allows insects to walk on water?
Surface tension
It is a force that acts on molecules at the surface of a liquid.
What is Transpiration?
Transpiration is the process by which plants release water vapor into the air through tiny openings in their leaves called stomata.
What is a scientific theory?
A well-supported explanation of a natural phenomenon.
What determines an atom's atomic number?
Atomic number
Which is a compound: O₂, CO₂, Au, or He?
Carbon dioxide (CO₂)
What is the difference between cohesion and adhesion?
Cohesion: Attraction between water molecules.
Adhesion: Attraction between water molecules and other substances.
What three parts of Earth are involved in the water cycle?
The atmosphere, land, and water.
Which is NOT a crucial step in planning an experiment?
A. Identifying variables.
B. Developing a control group.
C. Analyzing data.
D. Creating a hypothesis.
C. Analyzing data.
What role do electrons play in chemical bonding?
Electrons, especially valence electrons, are transferred or shared to form chemical bonds
What happens to atoms during a chemical reaction?
A rearrangement of atoms
Why does water expand when it freezes?
Water expands when it freezes because hydrogen bonds arrange water molecules into an open crystal structure that takes up more space than liquid water.
How does a hydropower Plant work?
Potential energy → Kinetic energy → Mechanical energy → Electrical energy
Potential energy: Water stored at a height.
Kinetic energy: Water moving through the pipes.
Mechanical energy: The rotating turbine.
Electrical energy: Electricity produced by the generator.
A scientist wants to investigate how sunlight affects plant growth. Identify the independent and dependent variables.
Independent variable: The amount of sunlight the plant receives.
Dependent variable: The plant's growth.
Why is understanding atomic structure important?
Understanding atomic structure helps us explain the properties of matter, how elements interact, and how chemical bonds and reactions occur.
Explain photosynthesis as a chemical reaction.
Photosynthesis uses light energy to convert carbon dioxide and water into glucose and oxygen.
How does water regulate Earth's temperature?
Water absorbs and releases heat slowly because of its high specific heat. This helps moderate Earth's temperatures and keeps nearby coastal areas from experiencing extreme temperature changes.
Describe the water cycle and explain how its processes work together.
Evaporation: The Sun heats liquid water in oceans, lakes, and rivers, turning it into water vapor.
Transpiration: Plants release water vapor into the atmosphere through their leaves.
Condensation: Water vapor cools and changes into tiny liquid droplets, forming clouds.
Precipitation: Water falls from clouds as rain, snow, sleet, or hail.