The main point of this simulation is to show that light rays leaving an object travel in straight lines. The simulation has two light bulbs that can be turned on or off independently. The bulbs can be dragged around the screen to change their positions. The light from the bulbs either passes through a mask with a hole in it, or it is blocked by an object, as it travels to a screen on the right of the simulation. Investigate how the patterns of light and shadows change as you move the bulbs, the mask or object, and/or the screen, and as you change the size of the mask or object.

For Teachers

# Activities

1. Start with the mask and just one of the light sources. This illuminates part of the screen. Let's say you wanted to illuminate a larger part of the screen. Could you do this by moving the light source? If so, do you move the light source toward the screen or away from the screen? Could you, instead, illuminate more of the screen by moving the mask? If so, do you move the mask toward the source or away from the source? Could you, instead, illuminate more of the screen by moving the screen? If so, do you move the screen toward the mask and the source or away from the mask and source?
2. Before you turn on the second source, predict the color that will be produced in a region that is illuminated by both sources simultaneously. Turn on the second source (so both the red source and the blue source emit light), and check your prediction.
3. Using two sources and the mask, determine the conditions under which the sources light up distinct (non-overlapping) regions on the screen, and when they light up overlapping regions of the screen.
4. Now use just one source and an object, which casts a shadow on the screen. Let's say you wanted the shadow to cover a larger part of the screen. Could you do this by moving the light source? If so, do you move the light source toward the screen or away from the screen? Could you, instead, produce a larger shadow on the screen by moving the mask? If so, do you move the mask toward the source or away from the source? Could you, instead, produce a larger shadow on the screen by moving the screen? If so, do you move the screen toward the mask and the source or away from the mask and source?
5. How do your answers to activity 1 compare to your answers to activity 4? Explain what the connection is between the two activitoes.

### Translations

Code Language Translator Run

### Software Requirements

SoftwareRequirements

 Android iOS Windows MacOS with best with Chrome Chrome Chrome Chrome support full-screen? Yes. Chrome/Opera No. Firefox/ Samsung Internet Not yet Yes Yes cannot work on some mobile browser that don't understand JavaScript such as..... cannot work on Internet Explorer 9 and below

### Credits

Andrew Duffy; lookang (This email address is being protected from spambots. You need JavaScript enabled to view it.); Tina Tan

### Pre-requisites/ Prior Knowledge

Pupils should be able/already known how to:

• Define what is meant by a light source.
• Give examples of light sources in their everyday lives.

### Sample Learning Goals

At the end of the lesson, pupils will be able to:

• Determine how light travels.
• Draw the path of light from a light source to our eyes.

### For Teachers

1. Recognise that an object can be seen when it reflects light or when it is a source of light.

2. Recognise that a shadow is formed when light is completely or partially blocked by an object

## Illuminating the Mysteries: A Primary School JavaScript Model Simulation Virtual Lab for Light and Shadows

 Light travel in straight line with dotted white lineswriteupdirect link

## Introduction:

The study of light and shadows is a captivating yet complex topic that forms the basis of our understanding of the world around us. To introduce primary school students to the fascinating concepts of light behavior, shadow formation, and the interaction of light with objects, we have developed a JavaScript Model Simulation Virtual Lab, original source code by Professor Andrew Duffy and further developed by lookang to suit Singapore syllabus . This virtual lab goes beyond the traditional single light source setup by incorporating three sources of light, a slit or object, providing an 2D and interactive learning experience. In this blog post, we will explore the features and benefits of our Light and Shadow Primary School JavaScript Model Simulation Virtual Lab.

## Exploring Light and Shadow Dynamics:

Understanding the behavior of light and shadows is crucial for comprehending a wide range of scientific phenomena. By engaging with the virtual lab, students can delve into the intricate interplay between light sources, objects, and the resulting shadows. This knowledge serves as a foundation for grasping concepts such as reflection, refraction, and the formation of colorful shadows.

## Features of the JavaScript Model Simulation Virtual Lab:

1. Multiple Light Sources: Our virtual lab incorporates three independent sources of light. Students can manipulate the position, intensity, and color of each light source, allowing them to observe the combined effects on shadow formation and object illumination.
2. Slit Interaction: The lab includes a customizable slit through which light passes. Students can modify the size and orientation of the slit to explore how these variables affect the characteristics of the projected light and shadows.
3. Object Interaction: Students can select different objects and place them in the path of the light sources. They can manipulate the object's size, shape, and position, observing the resulting shadows and their interaction with other objects and light sources.
4. Real-Time Simulation: The virtual lab provides a real-time simulation of the light sources, slit, objects, and resulting shadows. As students make changes, they can observe the immediate impact on the scene, promoting a deeper understanding of cause and effect relationships.
5. Experimentation and Data Analysis: The lab encourages students to experiment with different configurations of light sources, slits, and objects. They can collect data, measure and compare shadow sizes and shapes, and draw conclusions about how these variables influence the properties of light and shadows.

## Features

 Light travel in straight line with dotted white lineswriteupdirect link

 Light travel in straight line with dotted white lineswriteupdirect link

 Decrease distance of source from object, increases shadow size formed writeupdirect link
 Decrease distance of source from object, increases shadow size formed writeupdirect link

 Less distinct edges of shadow occurs when light source is near objectwriteupdirect link

 Less distinct edges of shadow occurs when light source is near objectwriteupdirect link

 What is wrong? pedagogical tool to identify wrongly modelled lighted parts when there is no lightwriteupdirect link

 What is wrong? pedagogical tool to identify wrongly modelled lighted parts when there is no lightwriteupdirect link

## Benefits of the Virtual Lab:

1. Interactive Learning: The JavaScript Model Simulation Virtual Lab engages students in active learning by allowing them to manipulate various parameters and observe the immediate effects. This hands-on approach stimulates curiosity, critical thinking, and a deeper understanding of light and shadow dynamics.
2. Visual Representation: The virtual lab provides vivid visual representations of light sources, slits, objects, and shadows. These visuals aid in conceptualizing abstract ideas and enhance students' ability to visualize the complex interactions of light.
3. Flexibility and Accessibility: The web-based nature of the virtual lab makes it easily accessible to primary school students across different devices. It eliminates the need for costly equipment and minimizes safety concerns associated with traditional experiments, enabling students to explore light and shadows anytime, anywhere.
4. Cross-Curricular Connections: The virtual lab facilitates interdisciplinary learning by connecting concepts from science, mathematics, and art. Students can explore the mathematical properties of light, create art with shadows, and develop critical thinking skills that extend beyond the boundaries of science.

## Conclusion:

The Light and Shadow Primary School JavaScript Model Simulation Virtual Lab offers an immersive and interactive learning experience for primary school students. By incorporating multiple light sources, a customizable slit, and object interaction, this virtual lab enables students to explore the intricate dynamics of light and shadows in a captivating manner. Through experimentation, data analysis, and visual representation, students can develop a strong foundation in the fundamental principles of light behavior. By fostering curiosity and critical thinking, this virtual lab paves the way for a deeper understanding of the natural world and nurtures a lifelong love for scientific exploration.

### Hands-on

Teacher will guide the pupils through the next part of the experiment.

Each group will be given:-

1. a torchlight
2. blank white paper
3. measuring cylinder

Using the materials given and imagine that the torch is our primary light source, which is the Sun, investigate if the different position of the Sun in the sky at different times of the day have any effect on the shadow formed by an object.

What do you notice about the shadow as you move the torch following the path of the Sun?

Is the length of the shadow the same throughout the day?

### Connected to Real Life

1. Long shadows are cast in the morning and evening when the sun is low in the sky.

2. Shadows are shortest at noon when the sun is directly overhead.

3. Shadows always point in the opposite direction from the sun.

### Video

Science - Light and Shadow - Basic - English bBodhaguru

Gruppe Pilobolus Amazing Shadow Dance by

Guiding Questions:

Show YouTube videos on shadow puppetry. Begin by investigating and asking the following questions: What is a shadow puppet? How are they put together? How do they move?  Where have you seen shadows? Can you make shadows creatures with your own hands?

### Research

http://www.lajpe.org/dec15/08_1019_Bulbul.pdf
first study is published in LAJPE: http://www.lajpe.org/dec15/08_1019_Bulbul.pdf
Dr. M. Şahin BÜLBÜL
http://www.fizikli.com/editor

### Version:

1. http://weelookang.blogspot.sg/2013/08/light-and-shadow-model.html an initial draft simulation for research by This email address is being protected from spambots. You need JavaScript enabled to view it.
2. http://weelookang.blogspot.sg/2013/08/refraction-model.html an initial remix based on Andrew Duffy's work
3. http://www.compadre.org/osp/items/detail.cfm?ID=9983 an original simulation by Andrew Duffy
4. https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejs_light_and_shadowwee.jar my dropbox copy of simulation by Andrew duffy and lookang
5. http://iwant2study.org/lookangejss/04waves_13light/ejs/ejs_light_and_shadowwee.jar server copy of simulation by Andrew duffy and lookang