Year 10 Science · Unit 2 · Lesson 14
Apply Worksheet
Learning Goals
Compare two
Complete the table to compare a valid investigation and a reliable investigation in the context of a reaction rate experiment.
| Feature | Valid investigation | Reliable investigation |
|---|---|---|
| What it means | ||
| How to achieve it in a rate experiment | ||
| Threat to this quality (give an example) | ||
| How to fix / check this quality | ||
| Can you have one without the other? |
Find the flaws
A student's reaction rate experiment
A Year 10 student investigated how concentration of HCl affects the rate of reaction with marble chips. Here is what they did: they tested four concentrations (0.5, 1.0, 1.5, 2.0 mol/L), but only ran ONE trial per concentration. They collected CO₂ in an open measuring cylinder without a lid or syringe, timing by counting seconds in their head. When drawing the graph, they connected the four data points with a bar graph instead of a line graph, since "the concentrations are numbers."
1. Identify the FOUR data quality problems in this experiment. For each one, name the problem (one sentence).
2. For each problem you identified, suggest a specific improvement. Which problem do you think is most serious? Justify your answer.
1. Write a CER (Claim–Evidence–Reasoning) conclusion for a reaction rate experiment where the data showed that doubling the HCl concentration doubled the initial rate of CO₂ production. Use specific values in your evidence.
Wrap Up
In one sentence, what was the main idea of this lesson?