Table of Contents
Activity 11.3- Measuring Distance with a Chessboard and Mirror
Objective- To explore how the distance of an object from a mirror relates to the distance of its image from the mirror.
Materials Needed-
- A chessboard or any grid-lined board.
- A small object like a chess piece or a toy.
- A plane mirror (a flat mirror without curvature).
- A ruler or measuring tape (optional but helpful).
Procedure-
- Set Up the Chessboard- Place the chessboard on a table. This board will help you measure distance accurately because of its grid lines.
- Place the Object- Put the object (like a chess piece) on one of the squares of the chessboard.
- Position the Mirror- Place the plane mirror upright at one end of the chessboard, facing the object.
- Observe and Measure- Look at the object’s image in the mirror. Use the grid lines on the chessboard to measure the distance from the object to the mirror and from the mirror to the image.
- Experiment with Distances- Move the object to different squares and repeat the observation and measurement. Notice the relationship between the distances.
Also Check – Class 7 Science -Chapter 15 – Light- Complete Notes
Also Check – Chapter 11- A Detailed Guide to the Light Activities for Class 7 Students
Core Concepts Explained-
- Plane Mirror and Image Formation- A plane mirror reflects light from objects in front of it, creating an image of these objects.
- Distance Relationship- The distance of the object from the mirror is the same as the distance of the image from the mirror. This is a key principle in the behavior of plane mirrors.
- Virtual Images- The images formed by plane mirrors are virtual, meaning they appear to be behind the mirror and cannot be projected onto a screen.
Possible Questions and Answers-
Why is the distance to the image the same as the distance from the object?
- This is because of how light reflects off a plane mirror. The light rays travel the same distance to the mirror and back, making the object’s distance and its image’s distance equal.
Can this principle be applied to all mirrors?
- This specific principle applies to plane mirrors. Curved mirrors, like concave or convex mirrors, have different rules for image formation.
What if the mirror is moved closer or further away?
- If you move the mirror, you’ll need to measure the distances again. The principle still applies- the distance from the object to the mirror will equal the distance from the mirror to the image.
Why can’t I see the image on the chessboard?
- The image is virtual, so it cannot be projected onto a physical surface like the chessboard. It’s an optical effect created by the reflection of light.
