HOW USE MAGNIFIER TO MAKE CAMERAS AND PROJECTORS?
First, cameras and projectors
Digital cameras used to be very hot. Since cameras in mobile phones have become better and better, digital cameras have rarely been used. Because the mobile phone is carried around, it is like a key and cannot be forgotten at home. If you do not take it with you for a while, you feel that something is missing. Walk to see the phone, watch the phone on the subway, see the phone on the bus. Why do you say this? That's because it's too boring. Who do I talk to in a strange place?
The projector is generally used when the PPT is placed in a meeting, because the display is too small and many people cannot see it. It can display larger fonts on a computer and has a magnifying effect.
Today, using a magnifying glass to do two experiments, cameras and projectors, simple and fun. This is an experiment I used to play as a kid. When I was a child, I had one feature: When I saw a fun experiment on a book, I would do it myself, so I accumulated a lot of experiments. It was not like the freedom of information now spread so quickly. And now I can freely show my fun experiments.
Second, experimental materials
A candle and a lighter
A magnifying glass
One A4 white paper
Third, the experimental steps
Light the candle and place the candle on something higher. I put it on the candy box. My candle is too low. If you have a long candle, you can fix it directly on the table.
Then fold the paper in half and place it on the mask box. Make sure that the vertical side is vertical and flat. Of course, you can use white paperboard to ride on one thing. This is more casual.
Pull on the curtains, then place the magnifying glass between the candle and the white paper, near some white paper. By the way, white paper and candles must be about 1.2 meters apart. The distance is too short to be successful. I tried it.
Move the magnifier slowly away from the white paper and you will see an inverted clear candle image
You can clearly see a small inverted candle, blow the candle, and the inverted image is also moving. This is the imaging principle of the camera and can be played more. The following experiment to do the projector is also very simple, change the position on the line.
This time, a magnifying glass is near the candle. Then slowly move the magnifier away from the candle and carefully watch the image on the white paper.
Wow, a big inverted candle is a lot bigger than the candle. If you move the white paper away, you will see bigger candles!
Fourth, the experimental principle
The magnifier is a special glass. Observe carefully that it is thickest in the middle and thin around. Physically, it has a focus. The distance between the focus and the magnifier is called the focal length.
In camera experiments, when adjusting the distance between the magnifying glass and white paper. There is always a position where the white paper is in focus and this is a clear inverted image. Why does the camera see an upright image? At that time, because there was a mirror inside the camera, we turned the inverted image into a standing image. The basic principle is the same, so how many focal lengths the single-lens camera often say is what the focal length of the lens magnifier is. Different focal lengths, the shooting distance is not the same. Macro close-up shots of close-ups, such as flowers and plants, and small animals. The wide-angle lens captures long-distance scenery and has a telescope function.
The principle in the projector is similar. When the candle is in focus, the magnifying glass projects the candle and is clear. The farther the white paper is, the more it has a magnifying effect. The same principle as the actual projector. Why do we see projector images standing upright? That's because there is also a mirror in it, which turns the inverted one into an erect one.
In fact, the best thing is to use a magnifying glass to burn the leaves under the sunlight. Just like the principle of the camera, only the sun is too far away from us. Even if it is imaged, it is still a small dot. When you play this experiment, remember to wear sunglasses, otherwise you will hurt your eyes. The focused sunlight is not only very hot, but also very bright. Protecting yourself is very important!
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