This experiment demonstrates the principle of refraction using a convex lens. A convex lens converges light rays passing through it, forming a real, inverted image on the opposite side.
By adjusting the distances between the candle, lens, and screen, you can observe changes in the image, illustrating how lenses are used in various optical devices like cameras, magnifying glasses, and the human eye.
By following these steps, you can effectively create a working model to demonstrate light refraction using a convex lens, candle, and cardboard.
Materials Needed:
- Convex lens
- Candle
- Cardboard
- Matches or a lighter (to light the candle)
- Ruler
- Scissors or a craft knife
- Marker
- Tape or glue
- A piece of white paper or a white screen (optional, for better visualization of the image)
Step by Step Video Instructions:
- Prepare the Cardboard Base:
- Cut a large, flat piece of cardboard to serve as the base of your experiment setup. This will hold the candle, lens, and screen (if used) in place.
- Set Up the Candle:
- Position the candle on one end of the cardboard base. Secure it with a bit of melted wax or glue to keep it stable and upright.
- Prepare the Lens Holder:
- Cut a small rectangular piece of cardboard to create a holder for the convex lens.
- Cut a hole in the center of this piece slightly smaller than the diameter of the lens, so the lens can fit snugly.
- Insert the lens into the hole. You can secure it with tape or glue if necessary.
- Set Up the Lens:
- Place the lens holder on the cardboard base, a specific distance from the candle (start with about 15 cm). You can adjust this distance later to find the focal point.
- Prepare the Screen:
- If you’re using a piece of white paper or a small white cardboard as a screen, place it on the opposite side of the lens from the candle. This screen will help you see the refracted image formed by the lens.
- Ensure the screen is aligned with the lens and the candle.
- Align the Setup:
- Ensure that the candle, lens, and screen are all aligned in a straight line. This alignment is crucial for observing the refraction and image formation.
- Conduct the Experiment:
- Light the candle and observe the light passing through the convex lens.
- Move the screen closer to or farther from the lens until you see a clear, inverted image of the candle flame on the screen.
- Measure the distance between the lens and the screen to understand the focal length of the lens.
- Observe the Refraction:
- Notice how the light rays from the candle flame converge after passing through the convex lens and form an image on the screen.
- Explain the phenomenon: The convex lens bends (refracts) the light rays such that they converge at a point (the focal point) to form a real, inverted image of the candle flame.