Inverse Square Law Lab

Purpose

To examine how the energy received (brightness) from a light source varies with distance.

Background

The brightness of an area can be measured with a light meter app such as the Android App or Apple App. Phones and tablets include front facing light meters so that they can adjust the screen brightness according to light conditions. This hardware can be exploited for carrying out this scientific investigation.

Task

Design and conduct a lab exploration that finds a relationship between brightness and distance from a light source. Your final lab write-up should include the following sections:

Grading Rubric

Section

Poor

Fair

Excellent

Intro:

Problem

Hypothesis

___/5pts

1 or more aspects is absent:__________

Hypothesis is not testable or linked to problem.

Problem statement is present, hypothesis is testable and linked to the problem.

Problem statement is clearly written, hypothesis is testable and linked to problem.

Procedure:

­­____/10pts

Many materials missing, procedure unclear or not in proper format, does not necessarily test hypothesis.

Most materials listed, procedure written clearly enough for someone familiar with experiment to follow in proper format and is designed to test hypothesis.

All needed materials listed, procedure is written clearly enough for anyone to follow in proper format (step by step instruction) and is designed to test hypothesis.

Data:

_____/5pts

Data is difficult to find and not clearly labeled. Precision and units not done properly.

Data is easy to find and clearly labeled but not necessarily to proper precision and some units missing.

Data is easy to find, clearly labeled to proper degree of precision and with units.

Analysis:

____/5pts

 Graph is not correctly formatted or axes are not labeled.

 Graph is correctly formatted with axes labeled.

 All graphs are correctly formatted, with axes labeled.

Conclusion:

____/5pts

Conclusion does not follow data, hypothesis is not mentioned, student does not demonstrate understanding of required concept.

Conclusion is directly linked to data and analysis there-of, though some outside information is mentioned. Student relates to the original hypothesis and it is clear they understand how required concept relates.

Conclusion is directly linked to data and analysis there-of and draws on nothing else. Student relates to the original hypothesis and it is clear they understand how required concept relates.

Evaluation:

______/5pts

Evaluation is missing needed aspects, and much of it is nonspecific.

Evaluation misses one aspect given under exemplary description. Some suggestions are not specific, such as – I could have measured better.

Evaluation clearly articulates problems with the experiment along with possible solutions and suggestion for further study. Everything mentioned is specific to the experiment at hand.

PHYSICS by MN Partnership for Collaborative Curriculum is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.