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Overview

Practice: Designing an Investigation

January 15, 2025
2 min read

Scenario: The Dissolving Sugar Mystery

To practice the skills learned in the “Puri” experiment, let’s apply the scientific method to a common kitchen observation.

Observation: You notice that sugar seems to disappear faster in hot tea than in cold lemonade.

Step 1: Formulate a Question

Q: Does the temperature of water affect how fast sugar dissolves?

Step 2: Identify Variables

Variable TypeWhat is it in this experiment?
Independent Variable
(What we change)
The temperature of the water (Hot vs. Cold).
Dependent Variable
(What we measure)
The time taken for the sugar to completely dissolve (in seconds).
Control Variables
(What we keep same)
1. Amount of water (e.g., 100ml).
2. Amount of sugar (e.g., 1 teaspoon).
3. Type of sugar (Granulated).
4. Stirring speed (e.g., stir 5 times).

Step 3: Experimental Setup (Diagram)

Experiment B: Hot Water

Glass 2: 100ml Hot Water

Add 5g Sugar

Stir

Measure Time T2

Experiment A: Cold Water

Glass 1: 100ml Cold Water

Add 5g Sugar

Stir

Measure Time T1

Step 4: Hypothesize

Based on the particle theory (which you will learn later in this book), we hypothesize that higher temperature makes particles move faster, so sugar should dissolve faster in hot water.

Step 5: Data Table Template

Create a table like this in your notebook when you do the experiment:

TrialTemperature (C^\circ C)Time to Dissolve (seconds)Observations
1Cold (10C10^\circ C)Water stayed clear longer
2Hot (80C80^\circ C)Sugar disappeared quickly
Note

Conclusion: If Thot<TcoldT_{hot} < T_{cold}, then our hypothesis is correct: Temperature increases the rate of dissolving.