Six questions unlock almost every Science item. Run them in order before you look at the options.
Ask | What you are identifying |
|---|
What is being studied? | The topic and the research question |
What evidence is provided? | The table, graph, passage or diagram you must use |
What is being changed? | The independent variable |
What is being measured? | The dependent variable |
What stays the same? | The controlled variables |
What conclusion does the evidence support? | What the data shows — not what you expect |
That last row is the one that decides marks. Choose what the data demonstrates, not what feels scientifically true.
A researcher tests whether pectinase increases juice production from apples. Beaker A gets pectinase. Beaker B gets distilled water. Both receive 50 g of chopped apple. Both sit undisturbed for 30 minutes. The researcher then measures the juice produced.
What is the dependent variable? The amount of juice produced. The researcher changes the treatment and measures the juice, so juice volume is the outcome. The 50 g of apple and the 30 minutes are controlled variables, and Beaker B is the control group.
Almost every experimental question rests on these five terms. Learn them as a set, because items usually ask you to tell one from another.
Term | What it means | Example |
|---|
Independent variable | What the researcher deliberately changes | Amount of fertiliser given to a plant |
Dependent variable | The outcome the researcher measures | Plant height after four weeks |
Controlled variables | Conditions held constant | Plant species, soil, sunlight, water, temperature |
Control group | The group with no experimental treatment | Plants given no fertiliser |
Hypothesis | A testable prediction | More fertiliser will increase plant height |
The common trap: a hypothesis is not correct simply because an experiment supports it. Evidence either supports a prediction or fails to. Answers phrased as "the experiment proves" are almost always wrong on the GED, because a single experiment proves nothing.
The second trap is a design flaw. If three fertiliser concentrations are tested but each group also gets a different amount of water, no growth difference can be blamed on fertiliser. Two things changed at once. A question asking how to improve the design wants you to hold water constant.
Graph questions look hard because they mix science with number work. They get easier if you check the structure before you read the trend.
Read the title. What relationship is being measured?
Check the x-axis. What variable runs horizontally?
Check the y-axis. What variable runs vertically?
Check the units. Minutes, grams, metres, degrees, litres?
Check the scale. Does one interval mean 1, 5, 10 or 100?
Identify the trend. Does the measured variable rise, fall or stay flat?
Compare specific values. Do not judge by how tall a point looks.
Steps 4 and 5 catch more errors than the rest combined. A misread scale produces a confidently wrong answer, because the shape of the line still looks right.
A researcher records bacterial growth at five temperatures:
Temperature | Bacterial growth |
|---|
10°C | 12 colonies |
20°C | 27 colonies |
30°C | 45 colonies |
40°C | 31 colonies |
50°C | 8 colonies |
Growth rises from 10°C to 30°C, then falls. Greatest growth is at 30°C, with 45 colonies.
If a follow-up asks which conclusion the data supports, the safe answer describes the observed relationship and nothing more. "Bacterial growth increases with temperature" is wrong here, because growth collapses after 30°C.
Probability = favourable outcomes ÷ total possible outcomes.
Suppose a population has 80 organisms and a genetic trait appears in 20 of them. The probability of randomly selecting an organism with the trait is 20 ÷ 80 = 0.25, or 25%.
Do not confuse probability with certainty. A 25% probability does not mean exactly one in every four future observations will carry the trait. Options phrased as guarantees are wrong, and this is the same reasoning tested in free GED science practice test items where observed results differ from predicted ones.
Genetics is where probability turns up most often. A Punnett square predicts 25% recessive offspring, but a real cross producing 19 recessive out of 96 gives 19.8%. That gap does not disprove the model. Chance variation in a finite sample explains it, and the item is testing whether you know that.
Life science is about 40% of the test. These are the items worth having on one page.
Structure | Role |
|---|
Nucleus | Contains genetic material and regulates cell activities |
Cell membrane | Controls what moves into and out of the cell |
Mitochondria | Main site of cellular energy production |
Ribosomes | Build proteins |
Chloroplasts | Carry out photosynthesis in plant cells |
DNA carries genetic information.
Genes are sections of DNA.
Alleles are different versions of a gene.
Dominant and recessive inheritance affect observable traits.
Homozygous means two matching alleles.
Heterozygous means two different alleles.
That gives 25% AA, 50% Aa and 25% aa. If A is dominant, the phenotype ratio is 75% dominant to 25% recessive. Keep the two ratios separate — the genotype split is 25/50/25 and the phenotype split is 75/25. Questions frequently ask for one and offer the other.
Producers → consumers → decomposers. Energy moves through a food web and is lost at each step; matter cycles rather than flowing one way. A fall in one population can affect several others, and questions usually ask you to trace that knock-on effect.
Also about 40% of the test, and the area people most often under-prepare.
Know the difference between an element, a compound, a mixture, an atom and a molecule. In a chemical reaction, reactants become products and atoms are rearranged rather than destroyed.
In 2H₂ + O₂ → 2H₂O, two hydrogen molecules react with one oxygen molecule to make two water molecules. Count atoms on both sides: four hydrogen and two oxygen either way. When a question asks what an equation supports, count rather than eyeball.
Know kinetic, potential, thermal and chemical energy, and that energy transfers or transforms between them rather than appearing or vanishing.
Speed = distance ÷ time. A vehicle covering 180 kilometres in 3 hours travels 180 ÷ 3 = 60 km/h.
Density = mass ÷ volume. A sample with a mass of 240 g and a volume of 80 mL has a density of 240 ÷ 80 = 3 g/mL. Check units before calculating — grams with millilitres, or grams with cubic centimetres, but never a mix.
The GED often gives you a table instead of naming the formula. Identify the quantities first, then decide the relationship.
This domain is about 20% of the test, so it earns roughly half the study time of the other two.
Topic | What to know |
|---|
Earth’s systems | Atmosphere, hydrosphere, geosphere, biosphere, and how they interact |
Weather and climate | Weather is short-term conditions; climate is the long-term pattern |
Water cycle | Evaporation → condensation → precipitation → collection |
Natural resources | Renewable versus non-renewable, and how human activity affects Earth systems |
Space | Solar system, stars, galaxies, and Earth–Moon–Sun relationships |
Official GED Science materials name electricity, motion, atoms, genetics, cells, weather patterns, natural resources and the solar system among the content students may meet. The official subject pages set out the current format.
You do not need a long formula list. GED Testing Service states that you are given the information needed to answer questions correctly rather than being expected to memorise formulas. That single fact should reshape how you revise.
What gets tested is recognition. A scenario describes a sample and its measurements without ever labeling one "mass" and another "volume". Knowing the formula is worth nothing until you can identify which number goes where. So practice reading scenarios and naming the quantities, rather than reciting relationships you already know.
The Assessment Guide for Educators confirms the reporting categories that carry your score: analyzing arguments and evidence at 30%, applying scientific processes at 40%, and reasoning quantitatively while interpreting data at 30%. None of those reward memorised facts on their own.
One caveat worth keeping. Not needing to memorise formulas is not the same as not needing to know any science. You still have to recognize what a food web or a chemical equation is before you can reason about one.
Print it and keep it beside your practice questions rather than reading it as an article. A cheat sheet works as a review layer over material you already understand, not as a replacement for learning it.
If a line here does not make sense when you read it, treat that as a signal to study the topic properly. That is the honest limit of any one-page reference, and the reason people who rely on cheat sheets alone tend to plateau. Pair it with timed practice from the free printable GED worksheets and the chart-reading strategy in how to pass the GED science test.
One last habit. After every practice set, check this page and mark which lines you actually used. The ones you reach for repeatedly belong on your printed copy. The ones you never touch are either already automatic or not worth the space.
