Focusing light
I can explain how light from an object can be focused by a converging lens to form an image.
Focusing light
I can explain how light from an object can be focused by a converging lens to form an image.
Lesson details
Key learning points
- Some of the light from objects can pass through a lens and become focused to form an image on a screen.
- Some light from every point on an object passes through every part of a lens.
- A convex lens refracts light rays so they travel more towards each other. A point where rays meet is called a focus.
- All the rays from one point on the object are focused to the same point, forming the corresponding part of the image.
- The shape of a converging lens refracts (bends) light more at the edges than near to the centre.
Common misconception
Each point of light on an image comes from just one ray of light from a corresponding point on an object.
Show how multiple rays of light from each point of an object pass through a lens and are focused at a single point in the image. Show how covering half of a lens does not cause half of the image to disappear.
Keywords
Lens - a piece of glass or other transparent material shaped to refract light towards or away from a focus
Image - a representation of an object
Focus - (1) a point where many rays of light from an object meet (2) the process of refracting light rays so they meet
Refraction - when light changes direction when it enters a new medium
Focal length - the distance from the centre of a lens to where the lens focuses a distant object
Equipment
convex lenses (magnifying glasses will do), plain A4 paper
Licence
This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).
Video
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