Scientific Investigation Lecture Notes

Science is the study of the world around us, helping us understand the "how" and "why" behind everything we see, hear, and experience in nature.
Without science, human understanding would rely primarily on guesses, myths, or traditions to explain natural phenomena.
A Scientific Investigation is a systematic process used by scientists to explore and understand the natural world. This approach involves asking questions, gathering evidence, and drawing conclusions based on observations and experiments.
The Scientific Method is a specific, step-by-step process used to solve problems.

Problem: Miguel noticed that his phone battery often drained quickly, especially when playing mobile games.
Question: "Does playing mobile games drain my phone battery faster than watching videos?"
Prediction/Hypothesis: Playing mobile games would use more battery than watching videos.
Materials: Smartphone, charger, stopwatch, and notebook.
Testing Procedure:
- The phone was charged to $100\%$ .
- The phone was used for $30\,\text{minutes}$ while playing a game.
- Remaining battery percentage was recorded.
- The test was repeated under the same conditions while watching videos.
Data Analysis: Comparing results from several trials showed that playing mobile games consumed more battery than watching videos.
Conclusion: Under the tested conditions, gaming drained the phone battery faster than watching videos.

This step requires defining the specific problem you want to solve or the factual information you want to know.
The problem is typically stated in the form of a question.
Example Scenario 1: A phone battery is low, but the phone will not charge when plugged into an outlet. Problem question: "Why won’t the phone charge?"
Example Scenario 2: Two slices of bread are left out; one is covered in plastic wrap and the other is uncovered. After $3\,\text{days}$ , the uncovered slice has mold while the covered one is fine. Potential questions include:
- "Why did the uncovered bread grow mold faster?"
- "How does plastic wrap affect mold growth on bread?"
- "Does covering bread slow down the mold growth?"
Trial Task: For butter placed in direct sunlight versus butter in a refrigerator for $10\,\text{minutes}$ , a question might be asked regarding why the sun-exposed butter softened faster.

This involves gathering basic information or making initial observations about the problem before conducting an experiment.
The goal is to understand the situation better by analyzing facts and looking for trends and patterns.
Example (Phone Charging Issue):
- Observe the phone screen: Does the charging icon appear? Is the phone completely dead or still on?
- Check hardware: Is the cable frayed, bent, or damaged? Does the charger feel hot or smell burnt? Is it plugged in properly?
- Environmental Check: Does the outlet work with other appliances? Does the charger work on a different phone, or does a different charger work on the original phone?

A hypothesis is an educated guess or a testable prediction about the outcome of an experiment based on existing knowledge or observations.
The Hypothesis Format: "If ___, then ___, because…"
- If: Describes the change or condition being tested (the independent variable).
- Then: Predicts the result or outcome (the dependent variable).
- Because: Explains the logic or reason behind the guess.
Example (Phone Charging): "If the charger is broken, then the phone will not charge when plugged into it, because a damaged charger cannot deliver electrical power to the phone’s battery."
Example (Butter Melting): "If butter is placed in direct sunlight, then it will melt faster than butter kept in the refrigerator, because sunlight provides heat that increases the butter’s temperature."

Independent Variable: The value or factor that is changed or manipulated on purpose. It is the "cause" and is controlled by the investigator.
Dependent Variable: The factor that changes in response to the independent variable. It is the "effect" and is the factor on which data is collected.
Variables in Specific Experiments:
- Water Temperature and Sugar Solubility: The independent variable is the water temperature ( $\text{hot, warm, cold}$ ). The dependent variable is the time it takes for sugar to dissolve (measured in $\text{seconds}$ ).
- Plant Growth and Water: The independent variable is the amount of water given each day. The dependent variable is the height of the plant.
- Soil Type and Growth: The independent variable is the type of soil ( $\text{sandy, clay, garden soil}$ ). The dependent variable is the height of the plant after $2\,\text{weeks}$ .

This step involves listing every tool, piece of equipment, and item needed to perform the experiment safely and correctly.
Proper planning ensures all necessary items, such as specific soil types or measuring devices for sugar dissolution, are available before starting.

Method and Procedure: This is the design of a step-by-step plan outlining how the experiment will be conducted.
Test the Hypothesis: This involves performing the experiment using the selected materials and following the procedure to see if the hypothesis is correct.
Purpose: Testing gathers real evidence to support or reject the hypothesis and determines if the independent variable truly affects the dependent variable.

Experimental data either supports or opposes the hypothesis and is usually presented in tables.
Qualitative Data: Information describing qualities or characteristics. Examples include "The water is cloudy," "The butter feels soft," or "The plant is green."
Quantitative Data: Information involving numbers and measurements. Examples include "The ice melted in $3\,\text{minutes}$ " or "The temperature is $25\,^{\circ}\text{C}$ ."

The conclusion is the final step explaining findings based on collected data and what was learned from the experiment.
Components of a Good Conclusion:
- Restate the hypothesis.
- Explain what the results showed.
- State whether the hypothesis was supported or not supported.
- Identify any problems encountered or new questions that arose.
Example (Plant Experiment): "The plant in garden soil grew the tallest. This supports my hypothesis that garden soil helps plants grow better. The sandy soil plant grew less, likely because it holds less water."
Significance: Conclusions demonstrate understanding, help others interpret results, and often lead to new questions or future investigations.