DepEd MELC reviewer for Grade 7 Science, Quarter 1. Master the concepts, tables, and common-mistake warnings below.
The Scientific Method
Steps: observe → question → hypothesis → experiment → analyze → conclude. Identify variables: independent (changed), dependent (measured), controlled (kept constant).
Classifying Matter
| Type | Description | Example |
|---|---|---|
| Element | One kind of atom | Oxygen, Gold |
| Compound | Atoms chemically combined | Water (H₂O), Salt |
| Mixture | Physically combined, separable | Air, Halo-halo |
| Solution | Homogeneous mixture | Salt water |
A compound can only be separated chemically; a mixture can be separated physically (filtering, evaporation).
Acids, Bases, and Solutions
Acids taste sour (pH < 7), bases taste bitter and feel slippery (pH > 7), neutral = 7. Concentration describes how much solute is dissolved.
pH 7 is NEUTRAL (pure water). Lower pH = more acidic; higher pH = more basic.
Identifying Variables
In "Does more sunlight make plants grow taller?":
| Variable | Example |
|---|---|
| Independent | amount of sunlight |
| Dependent | plant height |
| Controlled | water, soil, pot size |
Before your test, make sure you can confidently do each of the following:
- Explain and apply The Scientific Method.
- Explain and apply Classifying Matter.
- Explain and apply Acids, Bases, and Solutions.
- Explain and apply Identifying Variables.
Re-read any section above where you hesitate, then try the worked example again without looking.