VALID Science 8 cheat sheet

Science 8 - Core Reference

• Scientific method: observation → question → hypothesis → controlled experiment → data analysis → conclusion; a hypothesis must be testable and falsifiable.

• Independent variable is what the experimenter changes; dependent variable is what is measured; controlled variables are kept constant so results are attributable to the independent variable.

• A control group receives no treatment (or a placebo) and provides the baseline against which the experimental group is compared.

• Valid conclusions require repeated trials and large sample sizes; a single trial cannot establish a pattern or rule out chance.

• Metric units: length in meters (m), mass in kilograms (kg), volume in liters (L) or cubic centimeters (cm³), temperature in degrees Celsius (°C), force in newtons (N).

• Density = mass ÷ volume (D = m/V); water has a density of about 1 g/cm³, so objects denser than water sink and less dense objects float.

• Weight is the force of gravity on an object and is measured in newtons; mass is the amount of matter and stays constant regardless of location.

• SI prefixes: kilo- (×1000), centi- (÷100), milli- (÷1000); 1 L = 1000 mL, 1 m = 100 cm = 1000 mm, 1 kg = 1000 g.

• Valid evidence must be measurable, reproducible by others, and reported with units; anecdote, opinion, and a single observation are not sufficient scientific evidence.