Scientific Method and Experiment Design

Scientific Method

• Scientists use a series of steps called the scientific method to ensure their work is reliable.
• Steps include: asking a question, researching, making a prediction, experimenting, collecting results, and sharing results (or repeating if the prediction was incorrect).

Designing Experiments

• Experiments follow the scientific method.
• Experiments require a clear question, a hypothesis (a statement about what's expected based on prior knowledge), constants (factors kept the same), an independent variable (the factor changed), and a dependent variable (the outcome measured).
• The conclusion states whether the hypothesis was supported by the results.

Interpreting Data

• Scientific evidence is the data gathered during an experiment.
• To interpret data, check if it answers the question and supports or refutes the hypothesis.

Types of Variables and Controls

• Experiments involve variables, which can be changed.
• Three main types of variables: independent variable (changed by the scientist), dependent variable (measured as a result), and controlled variables (kept the same).
• Controls in an experiment help assess the validity of the results.

Timelines

• Timelines display events in order.
• To understand a timeline: read the title, look for the time periods (days, months, years, decades, centuries), and note the events and their sequence.

Engineering Design Process

• Engineers use a design process to solve problems.
• Steps of the engineering design process: ask, research, imagine, select and plan, create, test and evaluate, and improve.
• These steps can be repeated multiple times until a satisfactory design is reached.

Atoms and Matter

• Atoms are the basic building blocks of matter.
• An atom has a nucleus (containing protons and neutrons) and electrons orbiting the nucleus.
• Atoms bond to form molecules, which can be solids, liquids, or gases.

Electrons and Electrical Current

• Electrons are negatively charged particles, in constant motion within atoms
• Electrons generate electrical current.
• Atoms bond through the interactions of their electrons.
• Atoms of different materials have different numbers of electrons.

Valence Electrons

• Valence electrons are the electrons in an atom's outermost shell.
• These electrons determine how atoms bond to form new substances.
• Scientists use the periodic table to determine the number of valence electrons.
• Atoms strive to have eight valence electrons.

Molecules

• A molecule is a group of two or more atoms bonded together.
• The types and number of atoms determine the size and shape of a molecule.

Elements, Compounds and Mixtures

• Elements are composed of one type of atom and cannot be broken down further.
• Compounds are made from two or more different types of elements chemically bound together.
• Molecules are groups of atoms chemically bound together that can form compounds.
• Mixtures are composed of two or more compounds and/or elements that do not form chemical bonds.