Week 5:
We recapped what we knew about electricity flowing around a circuit in a loop, to e.g. light a bulb, and how if the circuit is broken then the bulb won't light.
We talked about how we might want to break a circuit on purpose, because otherwise the electrical thing, e.g. bulb, would be on all the time which is both wasteful and useless for all the time you don't need it! So what can we put in our circuit to break/complete it when we need to? A switch!
Our little circuit set came with a switch, which we looked at in a little more detail. It has a 0 and a 1 on it - why? 0 to mean it's off and 1 to mean it's on (useful to know in relation to binary code too!). An easy way to remember which number means what is that 0 means no power so off.
So how does a switch work? I had the girls build a simple series circuit from scratch each, independently, containing one cell, a bulb and a switch.
Then I asked them if we could use something else as a switch instead - what could we make a switch out from? What does it need to have? Two conductors which can break apart and touch together and an insulator around them so we don't get a shock when we touch it!
What could we use as an insulator? A piece of card folded in half maybe. What about as the conductor? M said we needed something metal, so what was there in the house which was metal?
Our making a switch investigation turned into a testing for conductors instead. 😂
They used the circuit with a single bulb they had made earlier and took out the switch, then they held one free wire each and touched the ends to the object they were testing. If the bulb lit up then it meant the object was an electrical conductor!
The objects they tested were: a £2 coin, a £1 coin, a key, the spine of a ringbinder, scissors (the blades and the handle), paper, a hair clip and a hair slide.
They came to the conclusion that all the metal things were conductors and all the non-metals were not! The metal hairclip didn't conduct electricity though... Why? Maybe because it was painted pink so the paint was an insulator? When they tried with a plain metal hairclip, they saw that the bulb did light up. 👍
Showing posts with label electricity. Show all posts
Showing posts with label electricity. Show all posts
Wednesday, 5 February 2020
Cells, Batteries, Bulbs & Series circuits
Week 3:
After recapping how to build a simple circuit (which they did independently, MashaAllah), I asked them where the energy in the circuit was coming from? They answered the battery.
I told them even though we call an AA battery a battery, it's actually just a cell, i.e. one part of it. When you have more than one cell together (hold up two AA batteries) then it's called a battery. So the AA batteries we use are actually called "single-cell batteries" because they only have one cell inside them. 😎
So looking at our circuit, how many cells does it have? One. And is the bulb shining very brightly? Not really... So how do they think we could make it shine brighter? F answered straightaway to add more cells. 👍 So I asked them to work together to build a circuit with one bulb and two cells, since at the moment they had a circuit with one bulb and one cell each. After a little arguing (lol) they managed and were pleased to see the bulb light up brighter! 💡
So I asked does that mean that if I keep on adding cells, making a bigger and bigger battery, then the bulb will keep on shining brighter and brighter? Or would something else happen? At first they laughed that it would, but then M said no because if you had too much power then the bulb would catch on fire. 😂
We read the page about how bulbs work in our KS1 Electricity book and then looked at one of the bulbs closely to see if we could see the filament (it was a little difficult so was there anything we could use to make it look bigger? A magnifying glass!). It was easy to see the filament when the bulb was on though, so need for a magnifying glass there! We talked about how the filament makes both light and heat (they touched the top of the bulb whilst it was lit up and compared it to what the top of a bulb which was off felt like) and how the filament can melt/the bulb "pops" - which is why we need to change the light bulbs in our house sometimes.
So if adding more cells to a circuit would make the bulb shine brighter (to a point!) then what would happen if we added more bulbs to a circuit, but kept the number of cells the same?
I asked the girls to help me design an investigation to find out, making sure we did things scientifically so everything was fair!
As they aren't expected to learn circuit diagrams at this stage, and to avoid overwhelming and complicating things, I had them draw the circuits pictorally instead.
So their prediction was that the energy from the battery would be shared equally between the bulbs... So when we tested it and only one bulb came on they were confused! We switched the bulbs in the bulb holders around to make sure it wasn't the bulbs which were broken and that it really was just one of the bulbs lighting up, then I drew a diagram of the three bulb series circuit on the board so we could talk about what we'd seen.
I asked the girls if they thought they could explain their conclusion, using what they know about the power in a circuit. F said the first bulb had used up all the energy so there was none left for the other bulbs to light up. So I asked them if that meant all the electricity had stopped at the first bulb? First they said yes, then they thought about it and said no - because if it had stopped at the first bulb then it wouldn't have carried on to make a loop and the circuit wouldn't have worked at all! So that meant the electricity going round the circuit and the power to light up the bulbs were two different things...
They understood it in the end as the first bulb taking all the power and not sharing it, but the electricity still went all around the circuit (no intention to introduce current, voltage and resistance at this stage!).
When they were done writing, I asked them what they thought would happen if they made a circuit using two fans next to each other. Would they both work or only one or? F said only one fan would work... Which makes sense based on what they'd just seen with the bulbs!
Week 4:
After a quick discussion about the investigation we did last week, I asked them again what they thought would happen if we built the same circuit with two fans. They answered confidently that only one would work, of course! So we tested it...
Both fans came on at the same speed. 😂
Now the girls were confused! The fans must be sharing the power like they thought the bulbs would last week! Were they really? How could we test it? Take one fan away from the circuit... Yes, it came on at a faster speed than two fans together!
But why? Was there something wrong with our bulb experiment then? How could we test it? Maybe repeat it with different bulbs?
The sets I bought came with 6 bulbs all together, so we made a circuit with two cells and two bulbs and swapped them in and out of the bulb holders in turn to see what would happen... We saw three different results:
1) one bulb bright, one bulb off
2) one bulb bright, one bulb very dim
3) both bulbs dim
So what did this all mean? We decided to look at the bulbs closely and they could see some numbers and letters marked on the side of the metal - 3 bulbs had 2.5V, 2 bulbs had 3V and 1 bulb was unmarked! So what would happen if we only used bulbs of the same type in the circuit?
Of course, they behaved in the same way as the fans did and shared the power equally!
They wrote up this separate conclusion after their original one.
This was a good (unplanned and unexpected lol) lesson in checking all the variables in an experiment and a good reminder to me to swot up on the subject beforehand - I completely forgot to check the bulbs first and assumed they were all the same! So I researched why the bulbs behaved the way they did after the girls wrote their first conclusion... I didn't have the confidence at the time to challenge it. 😂😅 And it was a good lesson in the scientific method and how mistakes help us learn. 😆
After recapping how to build a simple circuit (which they did independently, MashaAllah), I asked them where the energy in the circuit was coming from? They answered the battery.
I told them even though we call an AA battery a battery, it's actually just a cell, i.e. one part of it. When you have more than one cell together (hold up two AA batteries) then it's called a battery. So the AA batteries we use are actually called "single-cell batteries" because they only have one cell inside them. 😎
So looking at our circuit, how many cells does it have? One. And is the bulb shining very brightly? Not really... So how do they think we could make it shine brighter? F answered straightaway to add more cells. 👍 So I asked them to work together to build a circuit with one bulb and two cells, since at the moment they had a circuit with one bulb and one cell each. After a little arguing (lol) they managed and were pleased to see the bulb light up brighter! 💡
So I asked does that mean that if I keep on adding cells, making a bigger and bigger battery, then the bulb will keep on shining brighter and brighter? Or would something else happen? At first they laughed that it would, but then M said no because if you had too much power then the bulb would catch on fire. 😂
We read the page about how bulbs work in our KS1 Electricity book and then looked at one of the bulbs closely to see if we could see the filament (it was a little difficult so was there anything we could use to make it look bigger? A magnifying glass!). It was easy to see the filament when the bulb was on though, so need for a magnifying glass there! We talked about how the filament makes both light and heat (they touched the top of the bulb whilst it was lit up and compared it to what the top of a bulb which was off felt like) and how the filament can melt/the bulb "pops" - which is why we need to change the light bulbs in our house sometimes.
So if adding more cells to a circuit would make the bulb shine brighter (to a point!) then what would happen if we added more bulbs to a circuit, but kept the number of cells the same?
I asked the girls to help me design an investigation to find out, making sure we did things scientifically so everything was fair!
As they aren't expected to learn circuit diagrams at this stage, and to avoid overwhelming and complicating things, I had them draw the circuits pictorally instead.
So their prediction was that the energy from the battery would be shared equally between the bulbs... So when we tested it and only one bulb came on they were confused! We switched the bulbs in the bulb holders around to make sure it wasn't the bulbs which were broken and that it really was just one of the bulbs lighting up, then I drew a diagram of the three bulb series circuit on the board so we could talk about what we'd seen.
I asked the girls if they thought they could explain their conclusion, using what they know about the power in a circuit. F said the first bulb had used up all the energy so there was none left for the other bulbs to light up. So I asked them if that meant all the electricity had stopped at the first bulb? First they said yes, then they thought about it and said no - because if it had stopped at the first bulb then it wouldn't have carried on to make a loop and the circuit wouldn't have worked at all! So that meant the electricity going round the circuit and the power to light up the bulbs were two different things...
They understood it in the end as the first bulb taking all the power and not sharing it, but the electricity still went all around the circuit (no intention to introduce current, voltage and resistance at this stage!).
When they were done writing, I asked them what they thought would happen if they made a circuit using two fans next to each other. Would they both work or only one or? F said only one fan would work... Which makes sense based on what they'd just seen with the bulbs!
Week 4:
After a quick discussion about the investigation we did last week, I asked them again what they thought would happen if we built the same circuit with two fans. They answered confidently that only one would work, of course! So we tested it...
Both fans came on at the same speed. 😂
Now the girls were confused! The fans must be sharing the power like they thought the bulbs would last week! Were they really? How could we test it? Take one fan away from the circuit... Yes, it came on at a faster speed than two fans together!
But why? Was there something wrong with our bulb experiment then? How could we test it? Maybe repeat it with different bulbs?
The sets I bought came with 6 bulbs all together, so we made a circuit with two cells and two bulbs and swapped them in and out of the bulb holders in turn to see what would happen... We saw three different results:
1) one bulb bright, one bulb off
2) one bulb bright, one bulb very dim
3) both bulbs dim
So what did this all mean? We decided to look at the bulbs closely and they could see some numbers and letters marked on the side of the metal - 3 bulbs had 2.5V, 2 bulbs had 3V and 1 bulb was unmarked! So what would happen if we only used bulbs of the same type in the circuit?
Of course, they behaved in the same way as the fans did and shared the power equally!
They wrote up this separate conclusion after their original one.
This was a good (unplanned and unexpected lol) lesson in checking all the variables in an experiment and a good reminder to me to swot up on the subject beforehand - I completely forgot to check the bulbs first and assumed they were all the same! So I researched why the bulbs behaved the way they did after the girls wrote their first conclusion... I didn't have the confidence at the time to challenge it. 😂😅 And it was a good lesson in the scientific method and how mistakes help us learn. 😆
Saturday, 18 January 2020
Introduction to Electricity & Circuits
Week 1:
We read the first 6 pages from the Electricity book in the KS1 Science series we have, which gives a nice, simple introduction to the topic.
We looked at examples around the house of electric devices and made a distinction between mains and battery powered devices.
We talked about why electricity and electric items can be dangerous and how we should never play with them or touch them with wet hands.
We talked about insulators and conductors - in the context of how is it safe for us to use electric appliances if electricity is so dangerous? Because the inside of the appliance has conductors to let the electricity flow and the appliance to work but the outside is covered with an insulator which doesn't let electricity past so it's safe to touch. We talked about which kinds of materials are electric conductors (e.g. metals, especially copper, and water) and which are insulators (plastic and some others which we'll look at in more detail later InshaAllah).
(M remembered here about our work on insulators when investigating materials to keep a mug of tea hotter for longer, so we talked about what the words actually mean and how thermal insulators and conductors might be different to electric insulators and conductors... They should just think of the word insulator as to block or trap something as a wall does, and the word conductor as to let something through it easily or help it get past - I drew some simple diagrams on the whiteboard of arrows being blocked or going through a wall to help illustrate the point.)
We talked about how electricity is generated in power stations and the different kinds - e.g. water, coal - and whether it was better to use renewable energy sources or fossil fuels and why.
Finally, we watched a few of the relevant episodes from Blaze and the Monster Machines which were on Amazon Prime at the time (e.g. Episode 28 - Darington to the Moon! - features the characters visiting different kinds of power station).
--------------------
Week 2:
We read the double page spread about circuits in the Electricity book and talked about how electricity needs to flow in a loop to make things work. I showed the girls the battery from the remote control and how the ends were labelled positive and negative, how the remote control had a positive and negative sign where the battery fits inside and how we need to make sure the positive and negative signs match when putting the battery inside. I briefly told them about how the electricity moves from the negative end to the positive end in a circuit, which is why a loop needs to be made, but literally just as an introduction to the concept rather than expecting them to remember or understand!
We bought a simple circuit components set from Amazon (similar to this one, I can't find the exact link we used!) for the girls to experiment with. I did consider the Snap Circuits set, but I couldn't justify it for the price... And actually I'm pleased we went with this instead as with all the wires and clips it feels more raw and rewarding to do. 😆
I began by demonstrating how to build a simple series circuit with a bulb, narrating what I was doing so as to introduce the component names (wire, crocodile clip, battery holder, battery, bulb holder, bulb) and discussing with the girls which parts were conductors/insulators and how the electricity could flow from one component to the next. They could see clearly the copper wire from where it was exposed at the ends and how the screws were metal where the clips attached to the holders.
When the bulb was lit up (cue delighted gasps!) we talked about how there was a complete loop and how when the loop was broken the bulb would turn off.
I took away the bulb and replaced it with the fan and motor - introducing the component names first - and we talked about how the fan was able to spin... The motor was spinning and the fan was attached to it. The electric energy had been converted into movement (kinetic) energy, as well as a little heat from friction and some sound energy too. What was the electric energy turned into in the bulb? Light and some heat!
I disconnected the motor and showed the buzzer to the girls. We'd already converted electric energy to light and to movement, so what did they think this component did? F guessed heat and M said it looked like a hairdryer. 😂 When I connected it and it made a noise they both laughed and said sound energy! Then I told them the component was named a buzzer.
Finally, I took everything apart and asked them which was their favourite - the bulb, motor or buzzer? They both said the motor and fan. I gave them the necessary components (i.e. 2 wires, battery holder with battery inside and the motor with the fan attached) and challenged them to build a circuit to make the fan spin.
MashaAllah they managed and they really enjoyed it too! They could have played for longer tbh but it was dinner time so everything had to be put away. 😋
Later that week, we watched the film Monsters Inc. together and talked about how they got their energy not from electricity but from screams. 😁😁
We read the first 6 pages from the Electricity book in the KS1 Science series we have, which gives a nice, simple introduction to the topic.
We looked at examples around the house of electric devices and made a distinction between mains and battery powered devices.
We talked about why electricity and electric items can be dangerous and how we should never play with them or touch them with wet hands.
We talked about insulators and conductors - in the context of how is it safe for us to use electric appliances if electricity is so dangerous? Because the inside of the appliance has conductors to let the electricity flow and the appliance to work but the outside is covered with an insulator which doesn't let electricity past so it's safe to touch. We talked about which kinds of materials are electric conductors (e.g. metals, especially copper, and water) and which are insulators (plastic and some others which we'll look at in more detail later InshaAllah).
(M remembered here about our work on insulators when investigating materials to keep a mug of tea hotter for longer, so we talked about what the words actually mean and how thermal insulators and conductors might be different to electric insulators and conductors... They should just think of the word insulator as to block or trap something as a wall does, and the word conductor as to let something through it easily or help it get past - I drew some simple diagrams on the whiteboard of arrows being blocked or going through a wall to help illustrate the point.)
We talked about how electricity is generated in power stations and the different kinds - e.g. water, coal - and whether it was better to use renewable energy sources or fossil fuels and why.
Finally, we watched a few of the relevant episodes from Blaze and the Monster Machines which were on Amazon Prime at the time (e.g. Episode 28 - Darington to the Moon! - features the characters visiting different kinds of power station).
--------------------
Week 2:
We read the double page spread about circuits in the Electricity book and talked about how electricity needs to flow in a loop to make things work. I showed the girls the battery from the remote control and how the ends were labelled positive and negative, how the remote control had a positive and negative sign where the battery fits inside and how we need to make sure the positive and negative signs match when putting the battery inside. I briefly told them about how the electricity moves from the negative end to the positive end in a circuit, which is why a loop needs to be made, but literally just as an introduction to the concept rather than expecting them to remember or understand!
We bought a simple circuit components set from Amazon (similar to this one, I can't find the exact link we used!) for the girls to experiment with. I did consider the Snap Circuits set, but I couldn't justify it for the price... And actually I'm pleased we went with this instead as with all the wires and clips it feels more raw and rewarding to do. 😆
I began by demonstrating how to build a simple series circuit with a bulb, narrating what I was doing so as to introduce the component names (wire, crocodile clip, battery holder, battery, bulb holder, bulb) and discussing with the girls which parts were conductors/insulators and how the electricity could flow from one component to the next. They could see clearly the copper wire from where it was exposed at the ends and how the screws were metal where the clips attached to the holders.
When the bulb was lit up (cue delighted gasps!) we talked about how there was a complete loop and how when the loop was broken the bulb would turn off.
I took away the bulb and replaced it with the fan and motor - introducing the component names first - and we talked about how the fan was able to spin... The motor was spinning and the fan was attached to it. The electric energy had been converted into movement (kinetic) energy, as well as a little heat from friction and some sound energy too. What was the electric energy turned into in the bulb? Light and some heat!
I disconnected the motor and showed the buzzer to the girls. We'd already converted electric energy to light and to movement, so what did they think this component did? F guessed heat and M said it looked like a hairdryer. 😂 When I connected it and it made a noise they both laughed and said sound energy! Then I told them the component was named a buzzer.
Finally, I took everything apart and asked them which was their favourite - the bulb, motor or buzzer? They both said the motor and fan. I gave them the necessary components (i.e. 2 wires, battery holder with battery inside and the motor with the fan attached) and challenged them to build a circuit to make the fan spin.
MashaAllah they managed and they really enjoyed it too! They could have played for longer tbh but it was dinner time so everything had to be put away. 😋
Later that week, we watched the film Monsters Inc. together and talked about how they got their energy not from electricity but from screams. 😁😁
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