Year 4: Electricity
Electricity
Curriculum Requirement
- Identify common appliances that run on electricity
- Construct a simple series electrical circuit, identifying and naming its basic parts, including cells, wires, bulbs, switches and buzzers
- Identify whether or not a lamp will light in a simple series circuit, based on whether or not the lamp is part of a complete loop with a battery
- Recognise that a switch opens and closes a circuit and associate this with whether or not a lamp lights in a simple series circuit
- Recognise some common conductors and insulators, and associate metals with being good conductors.
Pupils should construct simple series circuits, trying different components, for example, bulbs, buzzers and motors, and including switches, and use their circuits to create simple devices. Pupils should draw the circuit as a pictorial representation, not necessarily using conventional circuit symbols at this stage; these will be introduced in year 6.
Note: Pupils might use the terms current and voltage, but these should not be introduced or defined formally at this stage. Pupils should be taught about precautions for working safely with electricity.
Pupils might work scientifically by: observing patterns, for example, that bulbs get brighter if more cells are added, that metals tend to be conductors of electricity, and that some materials can and some cannot be used to connect across a gap in a circuit.
National Curriculum in England: primary curriculum, Section: "Electricity", p. 164.
What is Electricity?
Electricity is a type of energy that makes things work. Look around your classroom or home. How many things are plugged into a socket or use batteries? These are all common appliances that run on electricity, like your telly, a tablet, a kettle, or the lights!
Building a Circuit
Think of electricity as a racing car. It needs a complete track to drive around. If there is a break in the track, the car stops. An electrical circuit is just like that! It's a complete, unbroken path that electricity can flow around.
The Parts of a Circuit
The Cell
This is what we often call a battery. It's the power source. It pushes the electricity around the circuit.
Its job is to:
Store chemical energy and turn it into electrical energy.
💡 Fun Facts
- A single battery is actually called a 'cell'. When you have two or more cells together, it's called a 'battery'.
- Every cell has two ends: a positive (+) and a negative (-). The electricity flows from the negative end to the positive end.
- The first proper battery was invented in 1800 by an Italian scientist named Alessandro Volta.
Nature's Battery: The Electric Eel
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A cell stores energy and releases it as electricity. Nature has its own version!
Nature's Equivalent:
The Electric Eel has special organs in its body that act like thousands of tiny batteries stacked together. It can release a powerful electric shock to stun its prey or defend itself.
💡 Fun Facts
- An electric eel's shock can be over 600 volts, which is more than twice as powerful as the electricity in our homes!
- Your own body is also electric! Your brain sends tiny electrical signals along your nerves to make your muscles move, and your heart beats using a tiny electrical pulse.
The Wires
Power cables are like the track for the electricity to travel along. We connect things that need power to electricity via power cables.
Their job is to:
Connect all the parts of the circuit together.
💡 Fun Facts
- Wires are usually made of metal (like copper) on the inside because metal is a great 'conductor' of electricity.
- The outside of a wire is coated in plastic, which is an 'insulator'. This stops the electricity from escaping and keeps us safe.
- The thicker a wire is, the more power it can carry.
- Electricity moves through the wires incredibly fast, at almost the speed of light!
Nature's Wires: The Nervous System
Wires carry electrical messages around a circuit. Your body uses 'nerves' to carry electrical signals around your body. Your body has an incredible network of nerves going all over the body.
Nature's Equivalent:
Your nervous system is a huge network of 'wires' called nerves. Your brain sends electrical signals down these nerves to tell your hand to move or your legs to run, just like a wire carrying electricity to a motor.
💡 Fun Facts
- Copper, the metal used in our wires, is also used by some animals! A horseshoe crab's blood is blue because it uses copper (not iron, like us) to carry oxygen.
- The copper in wires comes from rocks in the ground, a natural material formed over millions of years.
The Bulb (or Lamp)
This is the part that does a job, like light up! You could also use a buzzer to make a noise or a motor to make something spin.
Its job is to:
Change electrical energy into another type of energy, like light, sound, or movement.
💡 Fun Facts
- Inside a bulb is a tiny, thin wire called a 'filament'. When electricity flows through it, it gets so hot that it glows, giving us light.
- Early light bulbs didn't last very long. Modern LED bulbs can last for 25,000 hours or more!
- Thomas Edison is famous for inventing the light bulb, but a British man named Joseph Swan made a very similar one at the same time!
Nature's Bulb: The Firefly
A bulb turns electrical energy into light. Some creatures can make their own light using chemistry!
Nature's Equivalent:
A firefly or glow-worm uses a special chemical reaction inside its body to produce light. This is called 'bioluminescence' (which means 'living light'). They use it to talk to each other and attract a mate.
💡 Fun Facts
- Fireflies are super efficient! Unlike a light bulb, which wastes lots of energy as heat, a firefly's light is 'cold light' and wastes almost no energy.
- For a 'buzzer' equivalent, a rattlesnake has a special rattle on its tail, which it shakes to create a loud buzzing sound to warn off predators.
The Switch
This is like a drawbridge for your circuit.
Its job is to:
Open or close the circuit to turn it on or off.
💡 Fun Facts
- When the switch is 'closed' (or on), the bridge is down, and the electricity can flow across, completing the circuit.
- When the switch is 'open' (or off), the bridge is up, creating a gap. The electricity cannot jump the gap, so the circuit is broken and the bulb turns off.
- Your light switch on the wall is just a bigger, safer version of the switches we use in class.
Nature's Switch: The Venus Flytrap
A switch 'closes' a circuit when something makes contact with it. Plants can have switches too!
Nature's Equivalent:
A Venus Flytrap has trigger hairs inside its 'mouth'. When an insect lands and touches two hairs, it's like flicking a switch. The 'switch' is closed, a tiny electrical signal is sent, and the trap snaps shut!
💡 Fun Facts
- Your brain is the master switch for your whole body. It decides when to 'close the circuit' to send an electrical signal to your muscles.
- When you sleep, your brain 'opens' many of these circuits so your body can rest.
Conductors and Insulators
Some materials let electricity pass through them easily, while others stop it completely.
Conductors vs. Insulators
Conductors
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A conductor is a material that lets electricity flow through it really easily. Think of it as a perfect, wide-open motorway for the electrical energy to race along. It's the 'track' that electricity loves to travel on.
We use conductors, like the metal in your wires and the paperclip, to build a complete, unbroken path from the battery to the bulb so it can light up!
Examples:
Almost all metals are good conductors. This includes copper (in wires), steel (in paperclips), and silver and gold. The water in our bodies also conducts electricity.
💡 Fun Facts
- All materials have tiny particles in them called electrons. Metals are good conductors because their electrons are free to move around and carry the electrical charge from one place to another.
- Lightning is a giant spark of electricity in nature. It looks for the easiest path to the ground, which is why it often hits tall, wet trees or metal poles—they are good conductors.
- Our blood is a good conductor because it contains iron, a metal.
Insulators
An insulator is a material that stops or blocks electricity from flowing through it.
Examples:
Plastic, rubber, wood, and glass are all good insulators.
💡 Fun Facts
- Insulators are used to keep us safe. The plastic coating on wires and the plastic case on a plug stop you from getting an electric shock.
- Nature's Insulator: The wires in your body (your nerves) have their own insulator! They are coated in a fatty layer called a 'myelin sheath', which works just like the plastic on a wire, keeping the electrical signal trapped inside.
- The plastic used for wires is made from oil. This oil is a fossil fuel, which was formed from the bodies of tiny sea creatures like plankton that lived and died millions of years ago!
Why Birds Can Sit on Power Lines
Have you ever looked up and seen birds sitting on a big electrical wire and wondered why they don't get a shock?
It's because they are not part of a circuit!
Electricity needs a complete loop to flow. As long as the bird is only touching one wire, the electricity is happy to just stay in the wire and flow right past its feet. It doesn't want to go into the bird because there's nowhere to go.
💡 Fun Facts
- The bird is safe because it's not touching the ground (or another wire) at the same time.
- If the bird was very big and touched two wires at once, or touched the wire and a metal pole at the same time, it would make a circuit. ZAP!
- This is why it is SO dangerous to touch a fallen power line—you are standing on the ground, so you would complete the circuit!
Examples of how Nature uses Electricity
The Bee's Electric-KISS!
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Have you ever rubbed a balloon on your jumper and made your hair stand on end? That's static electricity. Bees use this to get pollen!
Nature's Example:
As a bee flies through the air, its furry body rubs against tiny air particles, building up a positive static charge. Flowers on the ground have a weak negative charge. When the positively charged bee gets close to the flower, the lighter pollen (which is also negatively charged) is pulled towards the bee. It jumps from the flower onto the bee's furry body, sticking to it like a magnet!
💡 Fun Facts
- A flower's electrical charge changes for a short time after a bee has visited. Other bees can sense this change and know not to waste time visiting an empty flower!
- A spider's web also uses the static electricity in the air to help it attract and catch tiny insects and bits of pollen.
- The "crack" you sometimes hear when you pull off a jumper in the dark is a tiny spark of static electricity, just like a mini-lightning bolt.
Nature's Quick Circuit: The Reflex!
Your body has special, super-fast electrical circuits called reflexes. These are automatic actions your body does without you even having to think!
Nature's Examples:
- Protection: If you touch a hot stove, the nerves in your skin send an electrical 'danger!' signal. This signal goes to your spinal cord (the big bunch of nerves running up the length of your back), which sends a signal straight back to your muscles, making you pull your hand away before your brain even feels the pain!
- Instinct: If you put your finger in a baby's palm, their hand will grab it tightly all by itself. This is the palmar grasp reflex, an automatic action they are born with.
💡 Fun Facts
- Reflexes for Protection: Blinking is a protective reflex. Your eye's nerves sense dust or fast movement and send an instant electrical signal to your eyelid to 'close the switch' and protect your eye.
- Reflexes for Survival: You have reflexes for basic survival. Coughing to clear your throat, swallowing your food, and a baby knowing how to suckle for milk are all automatic reflexes. Your body is using electricity to send messages around your body so it can react as quickly as possible.
- Reflexes that Bypass the Brain: The 'knee-jerk' reflex (when a doctor taps your knee) is a signal that goes from your knee to your spinal cord and straight back to your leg muscle, skipping your brain completely!
Nature's Faulty Wires: The Sun Sneeze!
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Do you ever sneeze when you suddenly look at a bright light? This is called the 'photic sneeze reflex'. It's like having 'leaky' insulation on your body's wires.
Nature's Example:
The 'wire' from your eye (the optic nerve) sends a big electrical signal to your brain when it sees bright light. This nerve runs very close to the 'wire' that controls your nose (the trigeminal nerve). In some people, the insulation around these nerves is a bit leaky, and the big 'light' signal sparks across and hits the 'sneeze' nerve by accident, making you go... ACHOO!
💡 Fun Facts
- This only happens to about 1 in 4 people.
- It's sometimes nicknamed 'ACHOO Syndrome', which stands for 'Autosomal Compelling Helio-Ophthalmic Outburst'!
- This shows how important insulation (called a myelin sheath) is for keeping our body's electrical signals on the right path.
Nature's Biggest Spark: Lightning!
A lightning bolt is a giant spark of static electricity.
Nature's Example:
Inside a storm cloud, tiny ice and water particles rub together, building up a huge static charge (like rubbing a giant balloon!). The bottom of the cloud becomes negatively charged, and the ground below becomes positively charged. The air acts as an insulator, but the charge gets so big that it 'jumps' the gap... ZAP!
💡 Fun Facts
- A single lightning bolt can be 100 million volts! (A cell is only 1.5 volts).
- The air around a lightning bolt gets five times hotter than the surface of the sun.
- Thunder is the sound of the air exploding outwards because it gets heated so fast by the lightning.
Nature's Spiderman: The Gecko!
How does a gecko walk up a glass wall? It's not glue, it's a kind of static electricity!
Nature's Example:
The bottom of a gecko's foot is covered in millions of tiny, tiny hairs. These hairs get so close to the wall that they create a tiny electrical attraction (like static cling) between the foot and the wall. This is enough to hold the gecko's whole body weight.
💡 Fun Facts
- Scientists are copying this idea (called 'biomimicry') to make super-strong 'gecko tape' that can stick things to a wall without glue.
- A gecko can 'unstick' its foot by simply peeling its toes, which breaks the tiny electric bonds one by one.
Your Body's Electric Drummer
Your heart knows when to beat because of a tiny, built-in electrical switch.
Nature's Example:
Your heart has a special group of cells called the 'pacemaker'. It acts like a tiny drummer. Every second, it sends out a small, regular 'zap' of electricity to the heart muscle, making it squeeze (beat!) in perfect time.
💡 Fun Facts
- When you run, your brain sends a signal to this 'pacemaker' to 'zap' faster, making your heart beat faster.
- Doctors can read this electric 'zap' using a machine called an ECG.
- If someone's natural pacemaker is broken, a doctor can give them a tiny, battery-powered one (like our 'cell') to do the job for it!
Activities & Reflections
Activities
Make a Simple Circuit
In small groups, use one cell, two wires, and one bulb. Can you figure out how to connect them to make the bulb light up? You must make a complete loop!
Add a Switch
Now add a switch to your circuit. Can you use it to turn your bulb on and off? Notice what the switch does to the 'loop' when you press it.
Conductor or Insulator?
Keep your circuit, but add a gap in it. One at a time, place different objects from around the classroom into the gap (e.g., a paperclip, a rubber, a coin, a wooden pencil, a piece of foil). If the bulb lights up, it's a conductor. If it doesn't, it's an insulator.
Test Your Reflex Circuit!
With a partner, sit on a high desk or chair so your legs can swing freely. Ask your partner to use the side of their hand to gently tap your knee in the soft spot just below the kneecap. Watch what happens! Your leg will 'kick' all by itself. This is your reflex circuit in action—you can't stop it!
Feel the Static!
- The Balloon: Rub a balloon fast on your jumper or hair for 10 seconds. Now, hold it just above your hair. What happens? Hold it near a wall. It should stick!
- The Polystyrene Pollen: Rub the balloon again. Break up some tiny pieces of paper or polystyrene packaging. Hold the balloon just above the pieces. They will 'jump' up and stick to it, just like pollen jumping to a bee!
Make Your Own Apple Battery!
You will need:
- An apple (a lemon or potato also works great)
- A galvanised (shiny/silvery) nail or screw. This is coated in a metal called zinc.
- A copper coin (like a 1p or 2p piece). This is made of copper.
- (Optional) An adult to help, and a tiny LED light.
What to do:
- Ask an adult to make a small cut in the apple, just big enough to slide the coin into.
- Push the copper coin into the cut.
- Push the zinc nail into the apple, about 2-3 cm away from the coin.
- Very Important: Do not let the coin and the nail touch inside the apple!
How it works: The apple's acidic juice acts like the chemicals inside a normal battery. When the two different metals (zinc and copper) are put into the acid, a tiny chemical reaction starts. This reaction 'pumps' a very small amount of electricity from one metal to the other, creating a simple circuit. You have made a real electrical cell!
Reflections
Self-Reflection (Exit Ticket)
On a piece of paper, draw a simple circuit that would make a bulb light up. Then, draw a circuit that would not work and circle the part that is wrong.
Paired Reflection (Think-Pair-Share)
Turn to a partner and explain: Why won't a bulb light up if one of the wires is not connected? Use the word 'loop' or 'circuit' in your answer.
Group Reflection
In your groups, look at a plug on the wall (do not touch it!). Discuss: Why is the plug made of plastic, but the pins that go in the wall are made of metal? Use the words 'conductor' and 'insulator'.
Whole Class Share-Out
As a class, let's make a list of our top 3 most important rules for being safe around electricity.
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