NOS
Put these steps of the scientific method in order.
Hypothesis, Observation, Analyze Data, Conclusion, Experiment
Observation → Hypothesis → Experiment → Analyze Data → Conclusion
What is an independent variable?
The variable that is changed by the experimenter.
What is the SI unit for length?
Meter
What is accuracy?
How close a measurement is to the true value.
A student concludes that fertilizer increases plant growth after one trial. What is wrong with this conclusion?
One trial is not enough evidence; multiple trials are needed to ensure reliability and rule out random error.
Why is it important to test a hypothesis with an experiment?
It allows scientists to gather evidence to support or reject the hypothesis using data rather than opinion.
What is a dependent variable?
The variable that is measured or observed.
What tool is used to measure mass?
Balance
What is precision?
How consistent repeated measurements are.
An experiment shows a pattern, but another scientist cannot repeat the results. What does this suggest?
The results are not reproducible, so they may not be reliable or valid.
What is the difference between qualitative and quantitative data? Give one example of each.
Qualitative = descriptive (color of a leaf). Quantitative = numerical (leaf is 5 cm long).
What are constant variables?
Factors kept the same throughout an experiment.
What does “kilo-” mean?
1000
Why are significant figures important?
They show the precision of measurements.
A researcher only records data that supports their hypothesis and ignores other results. What problem is this?
Bias; it can lead to incorrect conclusions.
Why do larger sample sizes increase reliability?
They reduce the impact of random errors and make results more consistent.
What is the difference between a control group and an experimental group?
Control = no change; Experimental = receives the change being tested.
Convert 1 meter to centimeters.
100 cm
How many significant figures are in 0.00450?
3
In an experiment testing how temperature affects dissolving speed, a student also changes the type of liquid used. Why is this a problem?
More than one variable is changed, so you cannot determine which caused the effect.
A student changes the amount of sunlight plants receive. Identify the independent and dependent variables.
Independent = sunlight amount; Dependent = plant growth.
What does it mean if results are reproducible?
Other scientists can repeat the experiment and get similar results.
Convert 2.5 km to meters.
2500 m
Calculate: 0.5 × 0.011 (correct sig figs).
0.006
Two groups perform the same experiment with different results. What should happen next?
Repeat experiments, compare methods, and analyze sources of error.