What are substances that transmit electric current called?

From the school physics course we know that electric current is the ordered movement of charged particles. In this case, at least two conditions must be met: the presence of free charge carriers and the presence of an electric field. Let us consider in more detail what substances conduct electric current, and what conditions must be created for this.

Common to all options is the mandatory presence of a field; only in this case is it possible to create a force that will be applied to the charge to move it from one electrode to another.

Project “Serial and parallel connection of batteries”

Volt is a standard unit of measurement for electrical voltage. Ampere is a standard unit of current measurement. Sequential - one after another, like links in a chain. Parallel - next to each other, like rails.

Electricity is the movement of electrons in a conductor, and voltage can be compared to the pressure of, for example, flowing water on a pipe. The current shows the number of electrons, something like the volume of water flowing out of a pipe. Batteries produce electricity through a chemical reaction. They can be connected in line to increase the voltage, or in parallel to increase the current. To increase both indicators, you can combine these types of compounds.

The series connection circuit involves connecting the plus of each battery to the minus of the next one. Two 6 volt 2 amp batteries connected in this way will produce 12 volts and 2 amps in the circuit.

The parallel connection scheme involves connecting pluses with pluses, and minuses with minuses. Two 6 volt 2 amp batteries connected in this way will produce 6 volts and 4 amps in the circuit.

A mixed connection allows you to combine both types of connection to obtain any desired voltage and current value. Thus, a voltage of 120 volts can be obtained by connecting 20 6-volt batteries in series. If a current of 50 amperes is required, and each battery provides 1 ampere, then the general connection diagram will look like 25 similar circuits connected in parallel.

One battery provides a small voltage and current. By connecting them in series, you can increase these indicators. Even a simple 9 volt battery is a collection of batteries. This project shows how combining batteries in different patterns can be used to achieve a wide variety of voltages and currents.

For children, this project can be very educational as it shows hands-on how electricity works. For example, four batteries can be used to produce 6 volts. Students can show their own electrical wiring diagrams.

The purpose is to demonstrate how multiple batteries can be used to increase the voltage and/or current in a circuit.

What we need:

• several batteries that will be connected in series and/or parallel;
• holders for them or wire and solder;
• a voltmeter that can also measure current;
• optional - disassembled battery.

Progress of the experiment:

1. Please note that every research paper on the topic of electricity requires compliance with safety precautions. There is a small risk of exceeding the permissible voltage/current level, which may lead to overheating of the entire structure. Soldering contacts makes the experiment more visual, but carries the risk of burns. When disassembling a dry battery, there is a risk of contact with the electrolyte.
2. Decide what you will use: a battery holder or solder.
3. Assemble a series circuit, measure voltage and current.
4. Assemble a parallel circuit, measure the voltage and current.
5. Create a circuit that combines both types of connections. Measure the same indicators.
6. Optionally, disassemble the battery and show its contents. Adult supervision is required as the electrolyte contained in it is caustic.

Conclusion:

What is electricity? What is a battery? What is a series circuit? What is a parallel connection diagram? Does a 9 volt battery contain one battery or several? Why? What is the difference between AC and DC?

Project "Resistance: Is copper the best conductor?"

Resistance is a set of obstacles to the flow of electrons. It is designated by the letter R. It depends on the length and thickness of the conductor, as well as on the material from which it is made, so the value may vary for different sections of it. It is measured in ohms (Ohm). The permanent property of a particular material to resist is called resistance, denoted by the Greek letter ρ (rho) and measured in ohm-meters (Ohm-m).

The formula for calculating the resistance of a given piece of wire looks like this:

R = ρL/S,

where R is the resistance in ohms, L is the length of the wire in meters, S is the cross-sectional area in square meters, and ρ is the resistivity of the conductor in ohm-meters.

Electrical conductivity is the reciprocal of resistivity. It shows how freely the material allows electricity to flow. It is designated G and measured in siemens (Cm). cm=ohm-1.

G= σ S/L,

where σ is specific conductivity.

Specific conductivity is inversely proportional to resistivity ρ.

σ = 1/ρ.

In this experiment, you will be able to calculate the resistance and conductivity of the materials being tested using Ohm's law, which defines voltage as the product of current and resistance. An ammeter will help you measure the current, and a voltmeter will help you measure the voltage.

V=IR,

where V is the voltage in volts, I is the current in amperes, and R is the resistance in ohms.

The goal is to find out the resistance of various materials, as well as calculate their conductivity.

What we need:

• 9 volt battery;
• 30 cm of thin and thick copper wire without insulation;
• 30 cm of thin and thick iron wire without insulation (with the same diameters);
• wires made of other materials;
• wire cutters;
• ammeter;
• voltmeter;
• ruler.

Progress of the experiment:

Observe safety precautions when working with electricity.

1. Connect the plus of the ammeter to the minus of the 9 volt battery.
2. Connect the negative of the ammeter to the end of one of the wires.
3. Connect its other end to the positive of the 9 volt battery.
4. Use a voltmeter to find out the voltage across sections of wire of different lengths (start with 2 cm, then measure for 3 cm, 4 cm and so on). Make sure that the plus of the voltmeter touches the beginning of the wire.
5. Record the current (from the ammeter) and voltage (from the voltmeter) for each length.
6. Use Ohm's Law to determine resistance and understand how length, thickness, and material affect it.
7. Display the results using a graph. Plot the length of the wire in meters on the x-axis, and the resistance in ohms on the y-axis.
8. Calculate resistance using the formula: R = ρL/S,
   Here R is the resistance in ohms,
9. ρ – resistivity in ohm-meters,
10. L – wire length in meters,
11. S is its cross-sectional area in square meters.
12. Use the conductor resistivity ρ to calculate the conductivity σ and conductivity G.

Conclusion:

Which material is more resistant? Conductivity? Formulate a hypothesis about the dependence of resistance on temperature.

The thinner the wire, the lower its resistance. Copper has a lower resistance, so it is considered a more suitable conductor of electricity compared to iron. Why? The longer the wire, the higher the resistance. Since it is a characteristic of the material through which electrons flow, it makes sense that the more material involved (in length), the greater the resistance. Resistance is a constant value for a specific material, so the resistance directly depends on the cross-section. In the graph of this dependence, the slope of the curve demonstrates resistance.

So, is copper a better conductor of electricity than iron? Yes, because electricity can flow through it with less resistance. This is a permanent property of copper.

Calculate the resistance of a certain section of wire using Ohm's law, since the elements of the circuit are connected in series, and the current strength is the same in any section.

Project “Plasma Ball! What is it and how does it work"

Experiments with electricity are always very exciting for children. Through this project, students will gain basic information about the plasma phenomenon and the application of the coil. Plasma is formed when gas atoms are heated to very high temperatures. As a result, the atoms have so much energy that when they collide, electrons are knocked out. Plasma itself consists of many electrons and ions.

The plasma ball is a device invented by Nikola Tesla in 1894, and it gained popularity in the 1980s. Essentially, it is a glass ball with an electrode in the center, filled with a mixture of inert gases. The principle of its operation is similar to the principle of operation of the Tesla coil. It contains a coil through which a very high frequency current is passed - the electrons in the coil oscillate very quickly and the surrounding atoms begin to lose their electrons, resulting in the formation of a plasma. Since some of the air has been pumped out of the balloon, it is very easy to create electrical sparks. Plasma is essentially a partially ionized gas whose ability to carry a negative charge makes it very sensitive to electromagnetic fields. Because of these unique properties, plasma is considered the fourth state of matter.

This experiment also allows children to become familiar with the basics of science—control, distinguishing between dependent and independent variables, collecting and presenting data, and making judgments about the validity and reliability of their findings. They act as scientists and learn to act like scientists.

The goal is to determine what a plasma ball is and how it works.

What we need:

• plasma ball (sold in toy stores);
• fluorescent lamp (sold at hardware stores);
• wooden (or non-metallic) stool or chair;
• a few coins and a multimeter.

Progress of the experiment:

1. Copy the table on the next page so you can quickly record your observations.
2. First, place your hand on the plasma ball. Write down what happened.
3. Now bring a fluorescent lamp to it. Write down what happened.
4. Ask your partner to help. Stand on a chair and place your hand on the ball. Do not touch the ends of the fluorescent lamp, but ask your partner to hand you the lamp. What happened? Record your observations.
5. Get off the chair. Stand on the floor and repeat step 5. What happened? Write it down!
6. Place the coin on top of the plasma ball. Now gently touch the coin with another coin. Don't touch it with your finger! You will be electrocuted!
7. Now measure the potential around the ball by placing one contact on its glass surface and the other nearby. Prepare an electric field diagram by measuring the entire space around it. Complete the diagram.
8. Write a report. Include all your observations and a diagram. Don't forget to include a list of references and basic information you obtained during your research. Did you like the project? What did you like? Are there any further steps you would like to take to learn more about the plasma ball and plasma itself?

Observation table

Figure: name the connections

Conclusion:

What is electricity? What is plasma? What are ions? What are noble gases? What is a Tesla Coil? How does it work? What are the safety precautions when working with a plasma ball? How is electricity generated and transmitted in it? Does the electric field look like the field next to a point charge? Can you find the equipotential lines? Can you calculate how much potential energy is needed to light a fluorescent lamp?

Dielectrics

There are no free charge carriers in dielectrics. The flow of electric current in such substances is impossible under standard external conditions. The most popular materials that do not conduct electricity are mica, ceramics, rubber and rubbers.

They can also include air and certain types of gases, but for them, the degree of pollution will be decisive. If there are a sufficient number of free ions, they lose their dielectric properties. Thus, one cannot blindly assume that any substance is an absolute dielectric and does not conduct electricity. Under certain circumstances, most substances known to be dielectrics can acquire the properties of semiconductors.

For example, iron oxide, which under normal conditions prevents the flow of electric current, becomes conductive when the pressure and temperature increase, while its internal structure is not disturbed.

To summarize, we note that the qualitative difference between substances that transmit or prevent the flow of electric current is their conducting state. For metals it is constant, and for dielectrics and semiconductors it is an excited phase. Conductivity is quantified in terms of electrical resistivity.

Project “Do Energy Drinks Contain Electrical Energy?”

To combat fatigue, many people drink energy drinks every day. This makes you feel energized. However, when you decide to drink another can of this drink, remember that it contains enough electrical energy to charge the battery. When electrons are transferred between two electrodes, they create an electric current.

The goal is to learn about different energy drinks and how much energy they contain.

What we need:

• energy drinks from different brands;
• water;
• jar;
• copper wire without insulation;
• zinc nail;
• voltmeter;
• sandpaper;
• notebook.

Progress of the experiment:

1. Make a table and list the ingredients contained in each drink. Point out significant differences.
2. Fill the jar with water and then attach one end of the wire to the voltmeter and the other to the nail.
3. Place the wire and nail into the jar. Make sure they are not touching.
4. Record the voltmeter readings. This will measure the amount of electricity in the drink.
5. Pour out the water, clean the can and lightly clean the nail and wire using sandpaper.
6. Repeat steps 2-4, conduct similar experiments with each energy drink. Record your observations.
7. Analyze the data. Which energy drink showed the highest electrical charge? Have you been able to identify the ingredient that provides the highest charge? Can this ingredient have a negative effect on humans?

Conclusion:

Can energy drinks power batteries and provide different levels of electrical charge? What ingredients in energy drinks cause differences in electricity levels?