Let's make a glass ball microscope.
Microscope making is one of the experiments that children brighten the eyes. In the worst case, you can make it without a glass ball. Introduced in Experiment 3. Please try it.
Material: Glass ball 3mm & 1mm (monotaro), PS sheet 2mm thick (Daiso), plastic sheet (side dish lid), thin plastic sheet, crack pin, cellophane tape, scissors, cutter
Make the PS sheet 10 x 2.5 cm in size. Make two holes smaller than the glass ball and place the glass ball on it. The perforated plastic prevents the glass balls from falling.
At this time, cut a thin plastic sheet as shown in the photo above. Focus can be adjusted by changing the distance between the lens and the sample at the bent part in the middle. Please use a thin plastic because it will move.
Make a horizontally long hole so that the plastic sheet can be moved sideways, and fix it. Draw a line in the visible range with either of the two lenses. Place the sample there. The sample is attached to the lens side with cellophane tape.
View from the PS side toward bright windows, fluorescent lights, PC screens, etc. To see the slide, lay the plastic sheet sideways and place the slide cover glass side on the lens side. After that, look at the lighting in the same way. If your desk is illuminated, try reflecting it in a mirror. How good the light is taken in by this microscope makes a big difference in how it looks.
Adjust the distance between the sample and the lens to focus. A 3mm lens has a magnification of 100x, and a 1mm lens has a magnification of about 300x. A virtual image is created if the sample is inside the focal length (the calculation formula is below). At this time, if an image is formed at a clear viewing distance of about 25 cm from the eyes, it will be clearly visible. Fluorescent lamps are good for lighting. The LED should cover visible light, but it seems that the image does not look good.
How to project an image on your smartphone
Use a large lens. Place the sample in focus and fix it with cellophane tape. Place it on the lens of your smartphone. When the lenses overlap, you will see a white circle on the screen. I can see it in this state, but there is not enough light. Shine the light from above.
Experiment 1: If there is a glass beads
Material: Glass beads 3mm, PET bottle, plastic (side dish lid)
When using a PET bottle, be sure to cut off the water leakage prevention part inside the cap. If you use it as it is, the lens will not be able to shorten the distance to the sample and it will not be in focus. The focal length that is in focus is written at the bottom.
Make a hole in the cap and place a glass ball of 3 mm on it. It will be fixed with cellophane tape from above. Originally, it is fixed with adhesive, but since the focal length of the glass ball 3 mm is long, the cellophane tape does not block the view.
Cut a plastic sheet (a side dish lid is OK) according to your mouth and fix it with cellophane tape.
Place the sample you want to see and attach it with cellophane tape. Cover with a lid and look at the bright side. Turn the lid to adjust the focus. If you can't see it very well, try shining light from below.
The magnification is 250 mm for a person's clear vision ÷ 2.25 mm for a lens focal length = 111 times.
you need : Glass beads 1mm, PET bottles, plastic
Cut off the upper part of the PET bottle from the shoulder. Carefully remove the protrusion on the inside of the lid. If it remains attached, it will not be in focus. Make a hole in the center of the lid and glue the beads. Be careful not to block the view of the beads!
As shown in the figure above, cut a plastic plate (such as a side dish lid) according to the size of the mouth and fix it to the mouth. Paste the material to be observed with cellophane tape. Look at the bright side from the lid as shown in the photo on the left. Depending on the size of the beads, 1 mm beads will be about 333 times larger.
About the magnification of a monocular microscope: It is determined by the ratio of the focal length of a glass ball to the clear vision distance of a human being.
The focal length of the glass ball can be calculated by the following formula. If R1 = R2 = r on a perfect sphere, then the formula on the right below is obtained.
If the radius r of the glass ball is r = 0.5 mm and the refractive index n = 1.5 of the glass is substituted into this equation, f = 0.75 mm.
What happens to the magnification of this glass ball with a diameter of 1 mm is that the human clear vision distance (the shortest distance to focus without putting effort on the eyes) is 25 to 30 cm. Assuming that a virtual image of the lens is formed at the position of the clear vision distance, a small ☆ becomes a large ☆ 25 cm ahead as shown in the figure below. From the relationship of the ratio of triangles (a: b = c: d), the size of the image is 250 mm for clear vision ÷ 0.75 mm for focal length = 333 times.
If you want to make your own glass beads , the glass when exposed to the flame of the burner from an oblique stretched thin the glass rod will fall becomes a sphere. If you leave the ladle and receive it, it will cool as a ball.
Experiment 2: If you make from glass rod
you need : glass rods, burners, black underlays, glass slides, cellophane tape
As shown in the figure on the left, when a thin glass rod is heated, it becomes spherical due to the surface tension of the melted glass. It is the same reason as the sparkler is rounded. This spherical glass is used as a lens to make a microscope of about 200x.
Next, cut the black underlay into 2 x 5 cm pieces. Make a hole with a diameter of about 1 mm in the center.
Bend both sides about 1 cm
.. As shown in c on the left, place a 1 cm stick on the glass ball in the hole and fix the stick with cellophane tape.
Place it on the slide as shown on the left. To adjust the focus, adjust the distance between the glass ball and the cover glass of the slide by pressing the plastic plate. Be sure to point the slide toward the bright side
At first, it is difficult to focus, so I think it is better to look at the slides that you have seen.
Experiment 3: microscope to make using the water droplets
It is a microscope made when there are no glass beads and no burner. The method of making is exactly the same as that of a glass bead microscope. Remove the protrusion on the inside of the lid, attach the table on which the sample is placed to the mouth, and place the sample.
Instead of glass beads, place a drop of water in the hole on the inside or outside of the PET bottle lid that is easy to put on. It is a mechanism in which water droplets replace the lens. I do it when I support developing countries overseas. Somehow I can see the cell wall of the onion. Why don't you give it a try? The photo on the right is an onion. I can see the core, but if I'm not used to it, it's hard to focus.
