Black in the Spotlight

Overview

How does light interact with matter? In this fun hands-on lesson, you students explore how different materials transmit, absorb and/or reflect light. They create their own experiments to demonstrate these phenomena and use a phones' built-in light sensor and Google's Science Journal app to add quantitative data to their arguments.

NGSS Alignment

This lesson helps students prepare for these Next Generation Science Standards Performance Expectations:

• MS-PS4-2. Develop and use a model to describe that waves are reflected, absorbed, or transmitted through various materials.

This lesson focuses on these aspects of NGSS Three Dimensional Learning:

Science & Engineering Practices	Disciplinary Core Ideas	Crosscutting Concepts
Developing and Using Models. Develop and use a model to describe phenomena. Planning and Carrying Out Investigations. Plan an investigation individually and collaboratively, and in the design: identify independent and dependent variables and controls, what tools are needed to do the gathering, how measurements will be recorded, and how many data are needed to support a claim. Engaging in Argument from Evidence. Construct, use, and present oral and written arguments supported by empirical evidence and scientific reasoning to support or refute an explanation or a model for a phenomenon.	PS4.B: Electromagnetic Radiation. When light shines on an object, it is reflected, absorbed, or transmitted through the object, depending on the object's material and the frequency (color) of the light.	Structure and Function. Structures can be designed to serve particular functions by taking into account properties of different materials, and how materials can be shaped and used. Cause and Effect. Cause and effect relationships may be used to predict phenomena in natural systems.

Materials

For the class:

• Laser pointer, class I or II. The Laser Safety Guide provides information on laser classification and how to use a laser safely.
• White paper
• Mirror
• Smartphone or tablet with Google's Science Journal app (for demonstration)
• Optional: scissors
• Optional: tape
• Optional: sheets of cardboard

For each team of 2 to 4 students:

• Flashlight
• Smartphone or tablet with Google's Science Journal app, available for free on Google Play for Android devices (version 4.4 or newer) or from the App Store for iOS devices (iOS 9.3 or newer).
  Note: This project was tested with the Android version of Science Journal in which light intensity is measured using the ambient light sensor and given in lux. The iOS version uses the phone's camera to measure brightness resulting in data expressed in EV (Exposure Value). Lux values and Exposure Values are not the same. Whereas Exposure Value is a base-2 logarithmic scale, the lux scale is linear. This might affect your data and result in different values and graphs when you are using an iOS version of the app—both versions will work for this project though. The graph examples given in the procedure show light intensity in lux.

For each pair of teams:

Cardboard box filled with:

• Sheet of aluminum foil or baking pan
• Small mirror
• Sunglasses
• Flat pieces of plastic: transparent, translucent but not transparent, one white and one black. Examples: a translucent folder divider, a white lid of a yogurt container, a black plastic food container (like a to-go box) with a clear plastic lid
• Sheets of paper: white(1) and black(3)
• A sheet of tissue paper (white or black) or tracing paper
• Optional: Ruler