Obstacles Block the Path of Light
Obstacles Block the Path of Light is a Grade 4 science skill from Amplify Science (California), Chapter 2 on how light enables vision. Since light travels in straight lines, any object placed between a light source and the eye interrupts the light path, blocking visibility and demonstrating why shadows form.
Key Concepts
Because light travels in straight lines, it can be easily blocked. An object that stands between the light source and the eye acts as an obstacle.
If an obstacle interrupts the path of light —either preventing light from hitting the object or preventing reflected light from reaching the eye—the object becomes invisible to the observer. An object's visibility is entirely dependent on an clear, uninterrupted line of sight.
Common Questions
How do obstacles affect the path of light?
Light travels in straight lines and cannot bend around objects. An obstacle placed between the light source and the eye blocks the path, making the object or area behind it invisible.
Why do shadows form?
Shadows form because objects block straight-traveling light. The area behind an obstacle receives no light, creating a dark region called a shadow.
What does it mean that light travels in straight lines?
It means light moves directly from the source outward and cannot curve. This property is why blocking the path with any solid object prevents light from passing through.
Where is this concept taught in Amplify Science Grade 4?
It is in Chapter 2: How does light allow a Tokay gecko to see its prey? in Amplify Science (California), Grade 4.