We learned that the image of a candle flame appears upside down on a wall when a cardboard with a hole is placed between the candle and the wall. The image gets sharper, when the hole gets smaller. We discovered this when Mr. Finley showed us a demonstration in the classroom. The reason for this is because the light rays travel in a straight path. The top light ray goes downward and the bottom one goes upward. Shown in diagram.
It is important to know this to provide an explanation for when images in real life appear upside down. Many things use this principle such as eyes, projectors, cameras, etc.
Later in the week, Mr. Finley gave us a quiz to see how much we understood about the light unit.
Our new topic is reflection. We learned that when the light rays from a laser hit a mirror, a small amount of light bounced everywhere, including our eyes and the rest (reflective ray) went in the opposite direction of the incident ray. To demonstrate this, we projected a laser pointer at a mirror and we observed what happened. See diagram explaining reflection below.
It is important to know this because it provides an explanation of why you see an exact "duplicate" in a mirror. Reflection is used when ballet dancers are rehearsing their movements and as safety devices such as rear and side view mirrors.
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