Physics in the second year of junior high school: what to do and how to do it

Regarding light, make a prism or underwater periscope.

Method 1 Materials: 3 pieces of transparent glass with a length of 10 cm and a width of 4 cm, and 2 pieces of equilateral triangular glass with a side length of 4 cm. Glass glue, water.

Production steps: Glue 3 rectangular glass sheets and 1 equilateral triangular glass sheet with glass glue into a triangular prism container (see Figure 1), pay attention to glue firmly and seal, wait for drying, fill the container with water, and seal the lid with glass glue to dry. to get a simple prism.

Method 2 Materials: 1 can, glass glue.

Production steps: cut and fold the can into a triangular prism container, and use glass glue to seal the container, add water to the container, and then use transparent tape to seal the opening slightly. Place the container in the refrigerator upright, freeze it and remove it.

Soak in hot water for a while, open the lid and remove the ice. You will be given an "ice cube prism". The canning container can be reused to make ice cubes.

Method 3 Materials: 1 washbasin, 1 glass mirror, clean water (tap water). White walls (or white paper).

Experimental steps: Add a small half basin of water to the washbasin, facing the sun, put a mirror into the water and also face the sun, let the sunlight find the mirror in the water and then reflect it on the white wall through the mirror, and at the same time refract the water surface from the water. , adjust the angle of the basin and mirror, and you will see a beautiful rainbow on the white wall.

Anyway, the third one has been done evenly, and it's very beautiful.

About the underwater periscope puppet elementary school nature class has been done, two fast small mirrors, two toothpaste boxes, ok·

As for the sound, it is okay to tie a few rubber bands on a template and make a dongdong similar to a guqin, or to make a drum on an iron box with a piece of toughness and dongdong.

Physically make light or sound?

Is that what it means?

Odd. What is physical production?

Please explain.

We first prepare the ingredients, empty drink bottles, foam fruit nets, and a glass marble, etc., and then we can get started.

We cut out the top half of the prepared empty bottle, divide the cut part into 8 parts, cut it to the neck of the bottle with scissors, and cut each part into the same large petals.

Then we put the foam mesh cover on the outside of the bottle, then we fasten it with a rubber band, and then we put another foam mesh on the glass marble and plug the bottle mouth, plug it tightly and expose about a centimeter.

We cut half of the table tennis ball, then cover half of the ball at the mouth of the bottle, and then trim the four sides into a whisker, the mouth of the bottle is fixed with a rubber band, and it is finished after beautifying it.

Summary 1 11To prepare the ingredients, cut out the top half of the empty bottle and divide the cut part into 8 parts.

2.The foam mesh sleeve is placed on the outside of the bottle and is secured with a rubber band, and the other foam mesh is placed on the glass marble sheet.

3.For half of the table tennis ball, cover half of the ball at the mouth of the bottle, then trim the four sides into a whisker shape and fix it.

Just do it according to what you have learned, and it doesn't have to be too complicated, such as the following picture:

Make a periscope.

To make a periscope, you only need two small square mirrors of the same size and a piece of cardboard. If your small mirror is ten centimeters long and seven centimeters wide, then you should prepare a piece of cardboard with a width of 4 7 = 28 centimeters. The length of the cardboard can be decided for yourself according to the conditions.

The cardboard is longer, and the periscope can be made taller.

Three parallel lines were drawn on the cardboard, each with a distance of seven centimeters, as shown in the diagram. Cut off the blacked-out parts. Use a knife to make a mark along the dotted line (be careful not to cut through).

Then, fold it around the table to make a rectangular box and glue it with kraft paper.

Glue the small mirror with white tape as shown in the picture below (so that the angle between the small mirror and the long carton is equal to 45°). Two small mirrors are aligned in parallel. In this way, a periscope was made.

1. Fruit battery.

2. Fire alarm.

3. Periscope.

1. Fruit battery.

A fruit battery is a trolley battery that inserts a chemically different metal into the fruit, so that a galvanic cell can be formed due to the acidic electrolyte in the fruit.

The principle of power generation of fruit batteries is that the activity of two metal sheets is different in the experiment, and the more active metal sheet reacts with the acidic species in the fruit to form hydrogen ions, and the whole system needs to be stable due to the electric charge generated (or an electric field is generated, and the electric field causes the following results. So in the case of a galvanic cell, the electrons keep the system stable from the loop, so theoretically the magnitude of the current is directly related to the concentration of fruit acid, (if it is to be expressed as a functional relationship, then this function is actually related to the ionic strength and is also a quantitative relationship, and the ion concentration is a qualitative relationship.) In this case, if the length of the circuit changes, it will inevitably cause the circuit to change, so it will also cause the voltage to change.

2. Fire alarm.

Materials: Neon bubble (that is, the glass bubble of the fluorescent lamp Chukri) in the starter, wire, battery, alarm (small bulb can be used, ** Kari's sound generating device) two wooden boards.

Production: Two wooden boards are nailed into a " " shape, and the neon bubbles are fixed on the vertical board (representing the wall); The other end of the board is connected to the circuit to connect the components in series.

Experiment: Bake neon bubbles with a lighter, and the circuit will be connected, and the light will turn on or the sound generating device will sound. It plays the role of reporting fires.

You can beautify your work according to your imagination and materials.

3. Periscope.

Buy two small mirrors. Make two right-angled elbow cylinders out of cardboard, slightly larger in diameter than a small mirror. Open a 45-degree oblique opening at the two right angles of the paper tube, insert the two small mirrors into the oblique mouth opposite each other, glue them with paper strips, and put the two right-angle cylinders together, that is, a simple periscope.