Wave in the house

This time we will make a mobile that demonstrates wave motion. It is very easy to prepare and can be created in one evening. The prizes will be: a working device, the opportunity to observe wave motion, conduct a series of related experiments and have fun.

A-priory manual halyardy is a mess that moves in space and changes in time. When mechanical waves propagate, the elements of the medium are ejected from the equilibrium position, and due to the elastic properties of the medium, the deformation covers more and more of its sections. The energy of wave motion is transferred in the form of a limited motion of the particles of the medium (kinetic energy) and in the form of deformation of the elements of the medium (potential energy).

Waves can be classified in different ways - for example, by the shape of their forehead, we can distinguish between flat, spherical and round waves.

The simplest example of wave motion is the waves that propagate in a circle on the surface of the water when a stone is thrown. We've all seen it, but let's look at рисунок. Observing the behavior of sticks or leaves floating on the water surface, it is easy to establish that the real movement of water molecules consists in their rise and fall in one place, and the wave itself, transmitting these vibrations, propagates over the water surface.

1. Finished model showing the wave phenomenon

2. Materials for assembling the model

3. Mark the hole locations with a ruler and pencil

4. Punch and hammer or cutting tools.

5. Choosing a drill according to the diameter of the screw

6. The skewer stick is easy to cut with pliers.

The medium does not move along with the propagating wave, but only its particles oscillate around the equilibrium positions, and the essence of the wave motion is to transfer them to subsequent layers of the medium.

The same thing happens when fans on the field demonstrate the so-called. mexican wave, getting up from chairs and sitting back down. Although they do not change places, you can see how the wave passes through the stands.

Here, one could smoothly move from sports to mathematics and plane wave equations, but we'll build a model to represent this and have some fun. This is the best place to start your adventure with science.

In this case, I suggest looking for materials and tools, and then immediately proceed to assemble the model. You don't have to work very hard to get the materials because they will probably end up in your home workshop (2).

Materials: board size 500 × 100 mm, 40 identical M4 nuts, two M6 bolts with nuts, twine or twine, several skewers.

Tools: pencil, ruler, pencil, perforator, hammer, screwdriver or drill, 5 mm drill, hot glue in a portion gun, pliers.

basis

It is a board with dimensions of 500 × 100 mm. At both ends, 20mm from the shorter edges, drill holes for M5 screws (6) with a 7mm bit. These bolts will be the supports for the string. First, however, we outline the places for the holes - draw them with a pencil (3), and then mark (4).

This is an important step that will make it much easier to accurately drill holes. Although it is easier to drill into wood than into sheet metal, the habit of punching holes will come in handy when doing DIY work. The holes will be used to attach the carriage bolts (5).

M6 screws, screwed into a board with a hole with a diameter of 5 mm, will even press their own thread into the wood. It is good to help yourself with their placement with a screwdriver. The screws must fit snugly into the hole. If it turns out that we drilled the holes too loosely, use hot glue.

7. Drill holes for screws

8. Insert the screws into the holes with a screwdriver.

9. Pull the thread well, then cut off the ends;

10. A cardboard template will help you determine equal lengths

11. Nuts and evenly cut sticks

Strings

We fasten the rope near their head. In the end, the string forms two lines, like strings well stretched and side by side. However, not too much. Finally, fix the ends of the rope with hot glue and cut off any unnecessary long ends (9). We will glue weights to these threads.

Chenzharki

They are made from the same and sword sticks. Each stick must be cut into pieces of 80 mm (6). We need 20 episodes. Using hot glue, glue a nut (11, 12) to each end of the stick. We cover the end of the stick with glue and insert it into the cap lying on the side. This will make your work easier and prevent your fingers from getting burned.

installation

Use a marker and ruler to mark equal sections on strings that are stretched like strings. Here you can use a pre-prepared cardboard template, which will allow us to correctly determine the length of the sections (10). It can be assumed that the distance between the weights should be 20 mm.

cover the places marked on the string fed from the whore gun. You can connect the strings with your fingers, smear them with glue and then release. The strings will return to their places, the glue will separate into each string separately, and we will put a weight on this place.

Place and glue the weights one by one (14). While the glue has not cooled down, we have time to fix it. Remember that the weights should be the same distance apart and remain perpendicular to the stretched strings.

Now our model is ready to go.

FUN TIME

Here are a few options you can try using our wave motion monitor.

Lightly tap the weight with your finger at the end. We observe a passing wave (15). It's not over because the traffic is back. We repeat our experience, this time hitting the middle. There is a difference? We can watch the wave of moving loads end and then return. Here's how it works.

The thread can stretch a lot over time. Then the model stops working. There is only one thing left: to pull the rope back.

Once we have enjoyed the wave motion alone and with friends, I suggest taking the model to the school physics lab. In addition, we also need to absorb a few more messages.

First, mechanical waves cannot propagate in a vacuum. diverge in centers of elasticity.

wave radius is the direction of wave propagation. The wave front is the collection of points that the wave reaches. wave surface is a set of points having the same phase of oscillation.

Mechanical waves (due to the situation) I divide into: linear (one-dimensional) - for example, on a rubber hose, surface (two-dimensional) - for example, on the water, spatial (three-dimensional) - for example, sound in the air.

Armed with this knowledge, we would surely impress a physics teacher if he wanted to make sure that the model was not just for raising grades. In any case, our curiosity and passion for experimentation will surely be rewarded.