[Music] Good day grade eight and welcome to tumamina teaching. My name is Lunell and I will guide you through this lesson of series and parallel circuits. This will be our fourth lesson of a series of five lessons in natural science term 3. We have a lot to do. So let's get started. Today we're exploring how electricity flows through different circuits. We're going to look at series and parallel circuits. These circuits are not just in your textbook, but it powers our lights. It's in TVs and even your cell phone charger. Before we dive into the content, let's remember a couple of things. A circuit is a complete path that allows electric current to flow. Just like water needs a pipe to flow, electricity needs a circuit. Can you remember some of the following keywords? Let's look at them together. The first keyword is power source which provides the energy like a cell or the batteries. The conductor is usually the metal wires that carry the current. The load is the part that uses the electricity like a bulb. And an open circuit is a gap in the path so the current cannot flow. Okay, grade eight, we're not there yet. Now it's your turn to work. Let's continue some revision and see if you can remember some key concepts. Are you ready? Let's go. What is a complete loop that allows the flow of an electric current? [Music] Yes, you are correct. It is a closed circuit. Next question. What is the flow of an electric charge through a circuit? Well done. You are correct. It is called a current. Now for our next question. What do we call the energy that pushes electric charges through a circuit? Great, you are correct. It is called voltage. Now for our last question. What slows down the flow of an electric current in a circuit? [Music] Good job. The final answer is called resistance. [Music] Now that we've refreshed our memories, let's look at how all these components come together in a circuit board. This is what you'll find in many electrical devices. A circuit board is a flat board that connects electrical components. Instead of wires running everywhere, the board has tracks that act like roads for the current to flow. A circuit board is made up of the following components. It has a holder for torch cells, metal pegs that are arranged for easy attachment of conducting strips. Conducting strips then connect the circuit components. Grade eight. It's important to know that some of these strips have holes for bulbs. Up to three torch cells can be placed in series in the holder. Crocodile clips can be used to connect cells to the wires in the circuit. The circuit board also holds components like resistors, LEDs, and capacitators. So, grade eight, we use circuit boards in our daily lives. We use it in TVs, microwaves, and many other electronic devices. [Music] Now that we know how circuits connect on a board, let's explore how they behave. First, we'll look at a series circuit. A series circuit has the following. One single path for the current to flow and the same current flows through all the components. The voltage is shared between the components. If one of the components break, the entire circuit will stop working. And lastly, the resistance increases as more components are added to the circuit. [Music] The other circuit is a parallel circuit. This setup gives each component its own branch like side roads of a main highway. A parallel circuit has more than one path for the current to flow and each component gets full voltage. If one bulb breaks, the others will stay on in one circuit. The current splits between the branches and the total resistance decreases as more branches are added to the circuit. For example, a home is wired in parallel. When your bedroom light goes off, the kitchen lights stay on. [Music] Great. Now, before we move on, we need to understand that in a circuit, there are metal resistors that give off high resistance and others that give off low resistance. Examples of metals that give high resistance are tungsten and nicro. And metals that give low resistance are like gold, copper, silver, and aluminium. Let's compare how currents, voltage, and resistance behave in both circuits. In a series circuit, the current is the same throughout. Whereas in a parallel circuit, it divides among the branches. [Music] When it comes to the voltage, it is shared between the components in a series circuit. But in a parallel circuit, it is full on each branch. [Music] Lastly, the resistance in a series circuit will increase with more components. And in a parallel circuit, the resistance will decrease with more branches. In a series, more components means more resistance and therefore dimmer bulbs. However, in a parallel, more paths means easier flow and as a result, brighter bulbs. [Music] Time to get hands on. Let's build both series and parallel circuits. I will hand over to my colleague, teacher Noel, who will show you how both circuits work. Over to you Noel. Welcome back to the lab. Today we're going to be looking at a simple series and a simple parallel electrical current. So at this moment we have a very basic series setup. So it's important to understand it goes from the batteries, the current flows through the two bulbs and then back to the batteries. So the current never splits. Um the same current goes through both of the bulbs. They're in the same branch. So, if I close the circuit, we're going to see that the two light bulbs, they burn, but they don't burn that brightly. Step two is going to be to build a parallel um circuit. And so, what I'm going to do, I'm just going to open the circuit so that the current is not flowing. And I'm going to take one of the bulbs and I'm going to put it in its own branch. So the two light bulbs are now in separate branches. So you can see here from the batteries the current is going to flow through uh the main circuit and then it's going to split into two separate branches. Here's one branch. Here's another branch. And then the branches come together again leading back to the battery. So, what you're going to see this time is that even though there are the same two light bulbs as which they were in the series um circuit because they're parallel, they are both burning quite brightly, much brighter than they burned while they were in series. Thank you, teacher Noel. That was very insightful. Let's do a reflection activity. I will give you some questions and you can answer them. Are you ready? Three, two, one, let's go. [Music] So, grade eights, how did you do? For question one, the bulbs were brighter in the parallel circuit. Why was that? Each bulb had its own branch and got the full voltage from the battery. In the series circuit, the voltage was shared between the two bulbs, so they were dimmer. [Music] So, how did you do with question two? Let's go over the answer. In the series circuit, there was only one path for the current to follow. Battery to bulb to bulb and back to the battery. In the parallel circuit, there were two separate paths, one to each bulb. The current splits between the branches. This tells us something important. The way we connect components affects how bright the bulb shines and how the electricity moves. Great work on noticing those differences. And just like that, we've reached the end of this lesson. Next time we'll dive into visible light, which is going to be very interesting. If you want to test your knowledge, follow the link in the description below and do the selfmarking quiz. See you next time. Bye. [Music]