SNC1W · Unit 1 test review

STEM Skills & Investigations: Test Review

Everything for the Unit 1 test on one page: the key facts from all 6 lessons, the mistakes that cost the most marks, and a practice test that points you back to the lessons you need.

Key facts

Questions, Hypotheses and Fair Tests

Independent variable: the one thing you change. Dependent variable: what you measure. Controlled variables: everything kept the same.
A hypothesis is a testable possible answer with a reason, often written "If … then … because …".
A control group leaves out the independent variable (or keeps it normal) so you have something to compare against.
Repeated trials and larger samples make results more reliable; average the trials.
Qualitative observations use words; quantitative observations use numbers with units.
Data support or do not support a hypothesis; one experiment does not prove it.

Measurement, Data Tables and Graphs

Prefixes: kilo (k) = 1000, centi (c) = 0.01, milli (m) = 0.001, micro (µ) = 0.000 001 of the base unit.
$1 mL = 1 cm^{3}$ , and $1000 mL = 1 L$ .
Read scales to the smallest marking plus one estimated digit; record all digits on a digital display.
Accuracy = closeness to the accepted value; precision = closeness of repeated measurements to each other.
$percent error = \frac{∣ measured - accepted ∣}{accepted} \times 100%$
Graphs: independent variable on the x-axis, dependent on the y-axis, units on both axes, a title, and a line of best fit for trends.

Research and Scientific Literacy

Judge a source by its author, date, evidence, purpose (bias) and whether it was peer reviewed or agrees with other reliable sources.
A scientific argument has a claim (the answer), evidence (the data) and reasoning (the science idea linking them).
Correlation (changing together) does not show causation (one causes the other); a third factor may cause both.
Peer review means other experts check a study before it is published; it catches many, but not all, errors.
AI tools can be powerful and wrong; check their output against reliable sources.
Two-Eyed Seeing (Elder Albert Marshall) brings together Indigenous and Western ways of knowing.

The Engineering Design Process

Engineering design cycle: define → research → brainstorm → choose and plan → build a prototype → test → evaluate and improve (repeat) → communicate.
Criteria are what the design must do (measurable goals); constraints are the limits (materials, cost, time, size, safety).
A prototype is a first working model built to be tested and improved.
Each round of testing and improving is an iteration; change one thing at a time.
Decision matrix: score × weight for each criterion, then add; the highest total wins.

Coding to Model Science

A variable stores a value; the = sign assigns a value to it.
A for loop repeats the indented lines; range(1, 6) gives 1, 2, 3, 4, 5 (it stops before the second number).
Growing by r% each step means multiplying by $1 + \frac{r}{100}$ each step (10% growth: multiply by 1.1).
Mean = sum of the values ÷ number of values; in Python, sum(values) / len(values).
A model is a simplified version of reality; check it against real data and improve it.

Lab Safety and WHMIS

WHMIS = Workplace Hazardous Materials Information System; updated in 2015 to match the international GHS.
WHMIS has three parts: labels, Safety Data Sheets (SDS) and worker education and training.
Supplier labels show the product identifier, supplier, pictograms, a signal word ("Danger" or "Warning"), hazard and precautionary statements, in English and French.
A workplace label is needed when a product is moved to another container that will be kept (not used right away); it gives the product identifier, safe handling information and a reference to the SDS.
An SDS has 16 sections, including hazards, first aid, spill clean-up, handling and PPE.
Chemical splash in the eye: rinse at the eyewash for at least 15 minutes and get help.

Where marks get lost

Changing two things at once, such as using more salt and a smaller ice cube. If the result changes, you cannot tell which change caused it. (Questions, Hypotheses and Fair Tests)
Mixing up the control group with controlled variables. The control group is one trial for comparison (no salt); controlled variables are conditions kept the same in every trial. (Questions, Hypotheses and Fair Tests)
Writing "the hypothesis was proven". Data support or do not support a hypothesis; they do not prove it. (Questions, Hypotheses and Fair Tests)
Giving "human error" as a source of error. Name the specific problem, like "the stopwatch was started late", and how to fix it. (Questions, Hypotheses and Fair Tests)
Running only one trial. A single result can be thrown off by one mistake; repeat each test and average. (Questions, Hypotheses and Fair Tests)
Putting the dependent variable on the x-axis. The variable you changed (independent) goes across the bottom; what you measured goes up the side. (Measurement, Data Tables and Graphs)
Connecting the dots point to point instead of drawing one smooth line of best fit that follows the overall trend. (Measurement, Data Tables and Graphs)
Mixing up accuracy and precision. Readings can agree closely with each other (precise) and still all be far from the true value (not accurate). (Measurement, Data Tables and Graphs)
Dividing by the measured value in percent error. Always divide by the accepted value. (Measurement, Data Tables and Graphs)
Multiplying when converting to a bigger unit. Kilograms are bigger than grams, so 3500 g becomes 3.5 kg, not 3 500 000 kg. (Measurement, Data Tables and Graphs)
Trusting a source because it looks professional or appears first in a search. Check the author, date, evidence and purpose every time. (Research and Scientific Literacy)
Treating a correlation as proof of cause. Two things that rise together may both be caused by a third factor. (Research and Scientific Literacy)
Writing a claim with no data, or listing data with no reasoning. A strong argument needs claim, evidence and reasoning together. (Research and Scientific Literacy)
Assuming an answer from an AI chatbot is correct. AI tools can state wrong facts confidently; check them against reliable sources. (Research and Scientific Literacy)
Rejecting all findings because one study was wrong. Science corrects itself by repeating and reviewing studies; look at what many reliable studies agree on. (Research and Scientific Literacy)
Mixing up criteria and constraints. "Must hold 2 kg" is a criterion (a goal); "use only 50 sticks" is a constraint (a limit). (The Engineering Design Process)
Building the first idea without brainstorming alternatives or checking it against the criteria. (The Engineering Design Process)
Changing several things between tests, so you cannot tell which change helped or hurt. (The Engineering Design Process)
Thinking a prototype that fails means the project failed. Failures show where to improve; that is the point of testing. (The Engineering Design Process)
Forgetting to multiply by the weights in a decision matrix, which treats a minor criterion like looks as equally important as strength. (The Engineering Design Process)
Reading = as "equals". In Python, = assigns: count = count * 2 means "replace count with double its old value". (Coding to Model Science)
Thinking range(1, 5) includes 5. It stops before the second number, so it gives 1, 2, 3, 4 (four passes). (Coding to Model Science)
Indenting a line that should run once (such as the final print) so it runs on every pass of the loop. (Coding to Model Science)
Modelling 10% growth by multiplying by 0.1 or adding 10. Growing by 10% means multiplying by 1.1. (Coding to Model Science)
Trusting a model's output without comparing it with real measurements. (Coding to Model Science)
Confusing the flame (the product itself burns) with the flame over circle (an oxidizer that makes other things burn more fiercely). (Lab Safety and WHMIS)
Thinking the exclamation mark means the most dangerous hazard. It marks less serious effects like irritation; the skull and crossbones marks serious poisoning. (Lab Safety and WHMIS)
Pouring a chemical into an unlabelled container. Any product moved to a container that will be kept needs a workplace label. (Lab Safety and WHMIS)
Sniffing a chemical directly or adding water to concentrated acid. Waft vapours toward you, and always add acid to water. (Lab Safety and WHMIS)
Rinsing an eye splash for only a few seconds. Rinse for at least 15 minutes and report it. (Lab Safety and WHMIS)

Practice test

24 questions from across the unit. Each one shows the lesson it comes from.

Questions, Hypotheses and Fair Tests
1
A student tests how the height a ball is dropped from affects how high it bounces. What is the independent variable?
Questions, Hypotheses and Fair Tests
2
A paper helicopter took 2.4 s, 2.6 s, 2.3 s and 2.5 s to fall in four trials. What is the average fall time, in seconds, to two decimal places?
s
Questions, Hypotheses and Fair Tests
3
Match each term to its meaning.
Independent variable
Dependent variable
Controlled variable
Hypothesis
Repeated trials
Questions, Hypotheses and Fair Tests
4
Which is the most useful source of error to write in a lab report about melting ice cubes?
Measurement, Data Tables and Graphs
5
What does the prefix micro (µ) mean?
Measurement, Data Tables and Graphs
6
A student measures the acceleration due to gravity as 9.60 m/s². The accepted value is 9.81 m/s². What is the percent error, to one decimal place?
%
Measurement, Data Tables and Graphs
7
A ruler is marked in millimetres. Which is the best way to record the length of a pencil that ends between the 14.2 cm and 14.3 cm marks?
Measurement, Data Tables and Graphs
8
A small stone has a mass of 27.0 g and a volume of 10.0 cm³. What is its density, in g/cm³?
g/cm³
Research and Scientific Literacy
9
Which source is most reliable for finding out how road salt affects Ontario streams?
Research and Scientific Literacy
10
Match each part of a scientific argument to an example about plant growth.
Claim
Evidence
Reasoning
Research and Scientific Literacy
11
Put these research steps in order.
1. 1Share your findings with citations
2. 2Combine what reliable sources say into an answer
3. 3Judge each source's reliability
4. 4Write a focused research question
5. 5Search for sources
Research and Scientific Literacy
12
Match each Canadian scientist or engineer to a contribution.
Frederick Banting
Donna Strickland
Elsie MacGill
Arthur McDonald
The Engineering Design Process
13
In a challenge to build a tower from spaghetti and marshmallows, which is a constraint?
The Engineering Design Process
14
What is the name for a first working model of a design that is built so it can be tested?
The Engineering Design Process
15
Match each term to its example from a bridge-building challenge.
Criterion
Constraint
Prototype
Iteration
Trade-off
The Engineering Design Process
16
Which of these careers is a skilled trade learned mainly through apprenticeship?
Coding to Model Science
17
What does this program print?count = 50 for day in range(1, 4): count = count * 2 print(count)
Coding to Model Science
18
What does this program print? Give the number as Python shows it.tea = 80.0 room = 20.0 tea = tea - 0.1 * (tea - room) print(tea)
Coding to Model Science
19
A student wants a population model to print 5 years, but it prints only years 1 to 4. The loop line is for year in range(1, 5):. What is the fix?
Coding to Model Science
20
Match each coding term to its meaning.
Variable
Loop
List
Comment
Output
Lab Safety and WHMIS
21
What does the flame over circle pictogram mean?
Lab Safety and WHMIS
22
Which signal word on a WHMIS supplier label means the more severe hazard?
Lab Safety and WHMIS
23
A classmate gets a splash of a chemical in one eye. What should happen first?
Lab Safety and WHMIS
24
Which pictogram has a round border instead of a diamond?

Endless drill

Fresh numbers every time, for the calculation questions in this unit.

Endless drillnew numbers every time

Generating a problem…