A rheostat is a small device that allows you to control voltage flow by using a knob or a dial.
Items you will need:
1. One (1) dry cell lantern battery or Two (2) “D” cell batteries.
2. A 2-inch long piece of wire
3. A socket and a bulb from a flashlight.
4. Roughly 16 inches of wire.
5. One pair of wire cutters.
6. A very long spring. This may be acquired from anywhere. A roll-up window shade has a spring inside the wooden portion. Ask a parent or adult to help.
1. When connecting the two batteries, connect them so that the negative pole of one battery is connected to the positive pole of the opposite battery.
2. Using the 16-inch wire, cut it in half with your wire cutters. Attach one piece to each open end of the joined batteries.
3. Using the light socket, connect one end of the wire to the terminal of the light socket and one end of the wire to one end of the spring.
4. Using the 2-inch wire, connect it to the other terminal of the light’s socket.
5. Taking the end of each wire, connect them. Pay attention to how brightly the bulb begins to glow.
6. Taking the short wire, slowly move it down the length of the spring.
Because the steel wire of the spring is not a great conductor of electricity, you will find that the further away you move the wire, the dimmer the light becomes. The more wire that the electricity is forced to move through the more resistance. Thus, you have less electricity. Congratulations, you have just created a rheostat! This device is used to calculate and vary the amount of current.
Electricity Projects, Grades 1-3 Science Projects, Grades 4-6 Science Projects
Ok, the above image is a bit of an exaggeration, but batteries do generate electricity (so to speak) by using two dissimilar metals and an electrolytic solution. This is the same principle that is used to turn veggies into batteries since vegetables and fruits are filled with natural electrolytic material, the most important component for electrically charged ions to move from one “pole” to another. In other words, they can help electric current to flow under the right conditions.
Potatoes are popularly used for making batteries with as many pairs of dissimilar metals as there are potatoes. The metals need to have sharp edges so that they can easily cut through the potatoes and make necessary contacts.
While copper and zinc are the most common metal choices, you can also try other metal pairs like copper and aluminium, copper and iron, aluminium and iron and so on. You’ll need as many short pairs of wire stripped at the edges as metal pairs. You also need an LED light preferably a red one as it’s more visible in daytime and requires minimum voltage for bright illumination.
Clean the potatoes and metal pieces to remove mud and dust particles. Scrub the metal pieces with sandpaper for a polished look. Secure the potatoes in containers and align them. Alternately insert the metals, starting from the first potato to the last.
Use the given wires and a soldering iron to connect the alternate metal strips from one potato to the other so that two ends of metals from the two extreme potatoes are free and open.
Add longer pieces of flexible wires to these ends and connect to the LED. If all connections are properly done, the LED will instantly give a bright glow, proving that there’s a reaction between the metals and potato’s electrolyte and a battery is formed!
Other fruits and vegetables
Not only potatoes, even lemons can generate electricity using similar metals, wires and an LED light. But lemons are more efficient at generating electricity as they are acidic in nature. Even bananas and strawberries can be made into batteries using the same principle.
Potatoes are most popular as they are rich in phosphoric acid, easily available and can be stored for months without attracting insects because of its sturdy starch tissue.
Or for a more prepared experiment, try one of these project kits …
How To Make Lightening
In this experiment, you’re going to be given two different methods for creating lightning at home. You can use this experiment during a science fair to simulate lightning as it occurs in nature. The items needed are usually found at home and this experiment is low in cost, requiring most to only purchase balloons.
What You Will Need:
1 large iron or steel pot. Do not use aluminum. (Make sure that your pot has a plastic handle.)
1 Iron or Steel fork
1 plastic sheet (a dry cleaning bag is a great option)
Method 1 Instructions:
Step 1: Tape the bag or sheet to the tabletop. (A large counter or kitchen island works too.)
Step 2: Put on your rubber gloves.
Step 3: Make the room as dark as you can. (You still want to be able to see what you’re doing.)
Step 4: Holding the pot by its plastic handle, rub it vigorously against the plastic sheeting. You want to build up as much static as possible.
Step 5: Holding the fork in the other hand, begin to slowly bring it toward the metal pot. When the distance between the two is short enough, you should be able to see an arc of electricity jump between the two objects.
What You Will Need:
A few inflated balloons
1 piece of wool clothing or a piece of animal fur. (Uh, no. Not your dog…or the cat.)
A metal surface like a doorknob or metal cabinet.
Method 2 Instructions:
Step 1: Inflate the balloons.
Step 2: Darken the room as much as you can while still being able to see what you’re doing.
Step 3: Rub one of the balloons against the piece of fur or the wool clothing. You want to build up as much static electricity as you possibly can.
Step 4: Slowly move the static-charged balloon toward the metal doorknob or whatever you’ve chosen that’s metal. You should see the electricity arc from the balloon to the metal object once they’re a short distance from one another.
After this shocking project, you might like to try this: http://how-things-work-science-projects.com/diy-electric-train/
The DIY Electric Train is amazing fun, easy to build, and a wealth of science that can be discussed at many levels. It does take a bit of concentration and a few key tips to make it work, which is why we put this at the 4th grade level.
But you be the guide. The more you want to help in its construction, the younger the student can be.
… and the deeper you want the student to get into the “why it works” part, the older they can be.
This featured video was created by “The Bearded Science Guy” and he does a nice job of introducing the topic at the middle school level.
So How Does The DIY Electric Train Work?
As was seen at about the 0:45 mark in the video, the “train” components from left to right were positioned so that we had a S pole then N pole for the 1st magnet, a S pole then North for the battery itself, but the last magnet was opposite at N then S pole.DIY Electric Train Battery Setup
When the “train” is placed into the coil, because the magnets are actually touching the copper wire, electricity from the battery flows through the magnets into the coil. When electrons flow through a coiled wire, that induces a magnetic field. And that magnetic field has polarity as well.
Because of the way the batteries are positioned, one end of the train is attracted (or pulled) by the coil’s induced magnetic field and the other end is repelled (pushed) by it.
But that only works if you put the right end of the train in the coil. If your first attempt does not work, just turn the train around and try again!
Other Things To Do
Coil separation, or the spacing between the coils matters and I recommend you test that to see how. If you make them too wide, then the coil’s magnetic field isn’t as strong and the train moves slower. Too tight such that the coils touch and the same thing happens. But something in between (like in the above video) works really well. Test this!
The type of magnets on the end can change things dramatically. Not all magnets are equal and “normal” magnets like you might use on your refrigerator won’t work. You need the new rare earth super magnets (neodymium magnets as noted in the video) for the project to work. The “old” magnets just don’t have enough strength.
The super magnets come in various “n-number” strengths up to n52, but n48’s work pretty good if you are using AAA batteries (and they are cheaper).
The number of magnets are also important. The more you put on (one would think), the more magnetic strength you have and the faster the train will go. Or will it?
Yes it will, up to a point. Once the magnets get too heavy then friction starts to slow things down.
If you want another source that discusses in detail how each variable affects the outcome, you can look here.
But I think it is more fun to try it and see for yourself … then try to figure out why.
Need More Detail For Older Students?
The above is a good start, but we really didn’t talk about how a magnetic field is induced in a wire, and we didn’t discuss how you can predict which direction that field will go in and just how that interacts with the “train” to be sure it will move through the coil.
We didn’t define how much current will be provided by the battery and we did not calculate field strengths.
We didn’t use right hand rules … in other words, there is a LOT that can be done to turn this simple, fun and entertaining experiment into a head scratch-er for high school science students!
After riding the rails with this one, take a look here for a simple but fun project: http://how-things-work-science-projects.com/lemon-battery-project/
A potato battery project is the last in a series of fruit and veggie battery projects included on this site. Many versions are available, but unless you want to get fancy with the voltmeter, fruit batteries make great science projects for kids since they are both inexpensive and relatively easy to perform.
A quick look at the lemon battery experiment will show it is the same science project, except that we use a potato here. As noted in that project, a fruit battery isn’t powerful enough to light a regular bulb.
A light emitting diode, (LED), could be used to show the effect since it requires much less voltage to illuminate. However, since the room needs to be very dark to see the LED light up, I selected the voltmeter method instead. In either case, it’s listed as a 5th grade science project if performed by itself. If demonstrated along with the “Turning on a Light Bulb” experiment, it could easily be used in elementary science projects from about the first grade on.
With that said, let’s make a potato battery …
We only need a potato, a couple nails and a piece of wire to make a potato battery. It’s a fun science project that helps show the way things work in a battery by using everyday items we see around the house.
As in the lemon battery the goal is to learn more about electricity, and possibly a few new science terms along the way. The project is designed to be performed on its own, but if the “Light Bulb” experiment is done at the same time, it can help connect the concept of a voltmeter reading to the familiar lighting of a flashlight bulb.
– 1 potato
– 3 to 4 in. copper wire with the insulation removed, #12 or #18 is ok, (a copper penny works too)
– 1 steel nail, #6 or 8 is good
– 1 zinc plated nail, #6 or 8 works fine
– Small piece of sand paper
– Wire pliers or a knife to remove insulation (not shown)
– A voltmeter that can read to at least tenths of a volt
To prepare for the potato battery project, simply gather the materials, remove insulation off the wire and lightly sand the nail ends so they will interact well with the potato.
Since the lemon and potato battery projects share the same steps, general concepts and “how it works” explanation, not all of that project info is repeated here. Major steps are listed, but please refer to the lemon battery experiment if more details are needed to conduct this lab.
Split the class into smaller groups as materials allow. If you plan to demonstrate the light bulb project at the same time, show how the battery makes the bulb light up. Shift focus from the light to the meter by showing that the meter moves if its leads are touched to the ends of the battery as well. Then ask … if we can make the meter move by connecting it to the potato instead of the battery, will that mean the potato is acting like a battery too? Let them know the correct answer is yes, assuming that really happens.
The nails and wire will be our test terminals for the potato battery. It does not matter which you start with, so pick any two to begin the experiment. Insert the ends about an inch deep into the potato and get them as close as you can without touching each other. (If they touch, no voltage difference will show and the meter will not move. If this happens, the battery is said to be ‘shorted’. Just pick a new spot on the potato and trying again).
Put the voltmeter on a DC setting. As an optional step, test the voltmeter on an actual battery (C for ex.) if you have one handy. Although not a necessary step for the project itself, it is a good time to discuss polarity if class schedule permits. It is easy to see which terminal is the cathode (+) and which is the anode (-) on a battery because they are stamped on it. By looking at the voltmeter display and swapping the red and black leads from one end of the battery to the other, you can show how the meter displays a minus sign one way, and not the other. This information can then be used to determine which of our test terminals acts as the cathode (+) and which is the anode (-).
Touch the red and black meter leads to the test terminals in the potato battery. (I tried steel and copper first). Take note of the reading, but don’t get too concerned if the values each group sees are different. Readings will probably vary from setup to setup, and from trial to trial. There are a few variables we can’t control with this setup, but getting a voltage reading at all … and noting the relative values of the readings as we try different terminal materials is what is important at this point.
Shift to another terminal combination. Zinc and steel are shown to the right. Again, note the voltage. Higher? Lower?
Try the final terminal set. As in the lemon battery project, you should see why zinc and copper make good terminals.
Take the voltmeter leads off the terminals and hold them apart. Note that there is no meter reading. Touch the leads themselves together. There is still no meter reading. Try poking the ends of the leads directly into the potato without touching the test terminals. Note again that no meter deflection occurs. A meter deflection only occurs when we set up the potato battery in one of the arrangements shown above. We need two dissimilar metals as the battery terminals, and they must be inserted into the potato for the battery to work.
Share with the group that what makes a flashlight bulb light up is the same thing that makes the meter move. It is called a voltage difference.
What just happened?
For the teacher – please see the lemon battery project for a detailed discussion of what’s happening. It is the same process that drives the potato battery. For more information on the theory behind the process, please see the Electricity Science Projects related to Charge section of the electricity page. PS – try raw first, then boil the potatoes and try it again to see what happens.
For the students – if the right metals are picked as battery terminals, a potato can in fact be turned into a battery.
To summarize, tell the group that even though the voltage in a potato battery isn’t strong enough to light a flashlight bulb, it really is the same process that makes a store-bought battery work.
And if you don’t have a multi-meter, or just want something more out-of-the-box for quick demonstrations, here are a few that should do that for you.
Here is another tasty battery project to try: http://how-things-work-science-projects.com/apple-battery-project/
Making a lemon battery is one of the classic science projects for kids. It is inexpensive, easy to set up and fairly easy to perform.
If you take a quick peek at the supplies photo below, you’ll see we need a voltmeter. Don’t let that scare you. A fruit battery doesn’t generate enough power to actually light a bulb, so a meter is needed to see the effect. That’s why I believe this is better suited as a 5th grade science project, if done by itself. However, nothing is hard and fast here. If you want to combine this with the “Turning on a Light Bulb” experiment to bridge the gap between lighting a bulb and seeing the meter move, it could be made to fit elementary science projects from about first grade on.
Enough of the intro stuff … let’s create a lemon battery – and then try to figure out how it works. Have fun!
What could be more everyday than a lemon, a couple of nails and some wire? Well, that’s all you need to make a lemon battery. As is the case with most science projects on this site, the goal here is to learn by using stuff we see around us in everyday life.
We will learn a bit more about electricity, possibly some new science terms, and if this project is done with the first grade “Light Bulb” experiment, we can tie a familiar flashlight operation to the more abstract concept of a meter reading.
– 1 medium size lemon or lime
– About 4 in. wire with insulation
removed, #12 or #18 works just fine
– 1 steel nail, #6 or 8 is ok
– 1 zinc plated nail, #6 or 8 is ok
– Small piece of sand paper
– Knife or wire pliers (not shown) to
– A voltmeter that can read tenths of a volt, but nothing fancy beyond that.
The lemon battery project requires almost no advance setup. Just gather the above material, strip the insulation off the wire and use the sand paper on the wire and nail ends just before performing the experiment.
Break the class into equal groups according to the number material sets you have available. If you are tying this to the battery light project, now is a good time to use the wire, flashlight bulb and battery to show how they are used to light the bulb itself. Tell them we will see if we can make the lemon into a battery like the one you are holding to light the bulb.
Order does not matter, but I selected a steel nail and copper wire to start with. They are our battery terminals. Lightly sand the end of the wire and nail. Without letting any part of the nail touch the wire, insert both ‘terminals’ in the lemon about 1 to 1 1/2 inches deep and as close together as you can get them.
Note – if they touch, our battery will be ‘shorted’ and no voltage difference will be shown on the meter. If that happens, just pick a new spot on the lemon and try again.
Turn the voltmeter on to a DC volt setting. If you have a battery handy (AAA, AA, C or D is fine), use it to show the class that the meter is really working. The meter will show 1.2 to 1.5 volts if new, depending on which you size you used, and possibly less if it is an old one. Let them know that it is this voltage difference that makes the light bulb in a flashlight come on, as well as the lights inside a car, or their car’s headlights at night when they need them.
Note – if the meter shows a minus sign “-” in front of the number, just switch the meter leads (black and red wires) around so that the black wire touches the other end of the battery.
Go ahead and touch one of the meter leads to the nail and the other to the wire. What happens? The reading you see may be different from one lemon to another, and from one trial to the next. This is because the voltage difference we see depends on how far apart the terminals are, how well we make contact with the meter leads, how much and how strong the juice (our Electrolyte) is in each lemon, as well as other things that we cannot easily control in this experiment.
The important thing to note is that there is definitely a voltage difference.
Replace the copper wire with the zinc nail. Touch a meter lead to each nail as shown in the photo. What happened with the lemon battery this time? Same voltage? Higher? Lower?
This time replace the steel nail with the copper wire. Zinc and Copper make great battery terminals. Can you see why?
If you demonstrated the experiment, try to give the students some time to do the lemon battery project themselves. Have them put the black and red leads directly together to show them nothing happens if there is no space between the meter wires. Have them pull the meter leads apart ever so slightly. That will show them nothing happens by itself even if the leads are very close together, but not in the lemon. Have them stick each lead directly into the lemon, close or far apart. That will show them nothing happens that way either. It only works when you have two different materials, close together but not touching in the lemon. But if you have the right two materials, it sure works then.
As a group, let them know the same thing that causes the light in a flashlight to come on is what causes the meter to move. If you decided to do the two projects together, go ahead and reinforce that by turning the light on again. You can even use the volt meter to show how the needle moves when you connect it to a “real” battery.
Then ask what they think would happen if you could hook up a light to the lemon instead of the battery. Now is your chance to let them know a bit about some basic electricity, a few science terms and perhaps even answer a few science questions about how things work.
What just happened?
For the teacher – as noted in Electricity Science Projects related to Charge, a lemon battery provides a potential difference much like in a car battery. Two dissimilar metals are immersed in the lemon’s juice, which acts as the electrolyte. The wire and nails act as the cathode (+ terminal) and anode (- terminal), and similar chemical reactions take place when the voltmeter is hooked up. Ions flow through the electrolyte and electrons flow through the wire.
If the terminals in our experiment are not connected to the meter, no voltage potential can be read. Likewise, if the two metals in the lemon are the same, the chemical reactions do not occur, no ions flow in the electrolyte and no voltage potential is generated … in other words, nothing happens. If we do use the right metals for our terminals, and we connect the voltmeter as shown in the above photos, we will get a voltage reading.
One question may remain … why can’t we turn a light bulb on with this battery? The answer is, even if we connected several lemon batteries together (in series) to get the same voltage as in a D cell battery, the current we can get out of a lemon battery is just too small to light the bulb. But it is fun to try!
For the students – as long as we have the right metals in the lemon, and we connect the voltmeter to each of those metals (battery terminals), we will read a voltage on the meter.
Summarize by letting them know – even though the voltage we see is small and our lemon battery just isn’t not strong enough to turn on a light by itself, it is the same thing that happens in a flashlight.
After the fruit battery series, try the Coin battery project. It’s pretty fun too.
And if you just want something you can pull off the shelf for quick demonstrations, these should help:
Here is another battery project you may want to have fun making: http://how-things-work-science-projects.com/potato-battery/
More fun with electricity for kids!
A coin battery is similar to fruit battery experiments, except that the fruit’s part is replaced by a small amount of salt water. It’s an easy science project to do, especially if a project like the lemon battery has already been performed.
Project supplies are plentiful and you can actually light an LED in this experiment if you stack enough coins together – – – but you have to get the right LED and making it work can be a bit tricky. So we’ll use a voltmeter to show the effect with the coin battery here. This is listed as a 5th grade science project, but if demonstrated along with the “Turning on a Light Bulb” experiment, it can be used in electricity experiments, or elementary science projects from about the first grade on.
How to create a coin battery …
To learn more about how electricity works.
The coin battery is designed as a stand-alone project, but if the “Light Bulb” experiment is performed at the same time, that can help connect what’s happening on the voltmeter’s display to lighting the bulb in a flashlight.
For each coin battery station, you’ll need:
– A small glass or bowl
– Spoon or stir stick
– Thick paper towel, blotter paper or even cloth
– About 6 each, pennies, nickels, dimes and quarters
– Small piece of sand paper
– A voltmeter that can read at least tenths of a volt
– Small battery, AA or AAA is fine
– Optional LED
The only preparation needed for the coin battery project is to gather the materials.
Split into groups as materials allow.
Use the AA battery as shown in the photo to the left to verify you have the meter set up correctly.
If the light bulb project is being performed at the same time as the coin battery, this is the perfect time to show how the battery can be used to make the flashlight bulb light up. Let the students know that if the meter moves using coins and salt water, then they must be acting like a ‘real’ battery as well.
Add a small amount of water in the glass or bowl. 1/4 cup should do just fine. Mix in enough salt such that a few grains no longer dissolve after stirring.
Cut about 8 – 10 pieces of the paper towel or soft cloth into sections that are just big enough to cover a nickel but do not hang over the side. To prevent problems, it is best to use the smaller coin, trace it out on the paper and cut the circles out with scissors. When done, place them in the salt water solution so that you can get them back out one at a time.
Lay out 6 nickels and place one piece of the salt-water soaked paper on each. Be sure that the paper covers the whole nickel, but don’t let it drape over the side. Lay a penny on top of each paper. Be sure the penny touches only the paper or it won’t work well. Each of the penny-paper-nickel stacks becomes an individual coin battery cell.
Turn the voltmeter on to a DC Voltage setting that shows at least one, and if possible, two or more decimal points as shown in the photo. Test each coin battery cell to make sure it is working as a small battery by putting one lead on the nickel and the other on the penny. You should see somewhere between .25 and .50 volts DC depending on how well that cell is working.
After each nickel/paper/penny cell is tested, set it on top of the previous cell. For example, after two cells are tested, you should have a nickel, paper, penny then another nickel, paper, penny. After three cells, you will have a nickel, paper, penny (no paper), nickel, paper, penny, (no paper), nickel, paper, penny … and so on. After stacking each new cell, put one of the voltmeter leads on the bottom nickel and the other on the top penny. With each new added cell, you should see a total voltage that is about the same as adding up what you measured for each individual cell that is now in the stack.
With 5 or 6 cells, the voltmeter should read at least 1.5 – 2.5 volts DC. As can be seen by the photo on the below left, 1.25 Volts were achieved with just 3 cells connected together. After about 3 cells, it gets hard to hold them all together without shorting out the battery. It is easier to build the coin stack on the table and use the points the meter leads to touch the bottom and top coins.
If you would like to take this one more step, 1.4V is enough to light a low voltage LED. You’ll have to be sure the current provided by the coin battery falls in spec with the LED, but give it a try! It’s well worth the effort if you can afford the time.
Try the other coins to see what happens. Make the paper or cloth big enough to cover most of the larger coin, but be careful not to let it fall over the side. You should see that some coin combinations make better batteries than others.
Be sure the students see that if the meter leads are held apart, touched together, or even put in the salt water by them self, nothing happens. Two dissimilar metals are needed to act as the battery terminals, and without them, no voltage is generated.
If you have trouble getting good readings, make sure that the paper does not drape over the side so that it touches other coins. That shorts the battery and little or no voltage will be displayed on the meter. If the water isn’t salty enough, it will not act as a good electrolyte. That means only a few ions will move from one coin to the other and you will have low voltage readings. If you put paper between the individual cells (see above for the correct stacking order), poor if any voltage will be generated.
Those are the most common problems, but if all that seems to be ok and the meter still won’t read, try lightly sanding the coin surfaces with a small piece of sand paper. That should fix it.
What just happened?
For the teacher – except for salt water replacing the fruit, most concepts and “how it works” explanations are the same here as in the fruit battery projects. Please see the lemon battery experiment for a complete explanation of what’s happening in the coin battery. Additional information is also discussed in the Electricity Science Projects related to Charge section of the electricity page.
Where this experiment differs from fruit battery projects is that we connect several batteries together in series to get enough voltage to light an LED. That means we connect the (+) terminal of one battery to the (-) terminal of another.
It is also why we do not put the salt-water soaked paper between individual battery cells. If you look closely, you’ll see doing that connects a zinc-copper battery to a copper-zinc battery. In other words, if you use the wet paper between cells, you will have a (-) nickel terminal connected to a (+) copper terminal, then the same (+) copper terminal is immediately connected to a different (-) nickel terminal when you put the next nickel on the stack. You can think of this as positive voltage going one way, but being immediately cancelled out by negative voltage going the other way. The net effect is no total voltage.
By leaving the wet paper (electrolyte) off between each individual battery cell, there is no electrolyte to force copper and zinc ions to flow. Only free charge will flow from one cell to another through the metal-to-metal contact. When more than one battery cell is included, the voltage increase becomes additive, and you see the effect we saw during the experiment.
This was first performed by Alessandro Volta in something he called a voltaic pile way back in 1800. He used alternating copper and zinc or silver and zinc discs that were separated by cardboard or cloth soaked in salt water, just like we did above. Since some metals have more free electrons to give up or accept in ionic form than others, some dissimilar metal combinations work better as batteries than others. If you tried different coins above, you should have seen that effect. If you tried two of the same coins together, penny – paper – penny for example, you would also see that coins with the same metal in them will not give you a battery at all.
If you wanted to go back and connect several potato, lemon or apple batteries together in series like we just did with the coins, you can see the same additive effect with the voltages. It does not matter what generates the voltage, it only matters that you connect them in series correctly to see the effect. In fact, you could make one battery from each of the above, connect them in series, and you should see a final overall voltage that is very close to the sum of each individual battery cell in the group.
For the students – as long as we choose the right coins for our terminals, and are careful about how we connect them together, we can turn pocket change into a battery.
Summarize by telling the group – each individual coin battery, one penny, one piece of salt water soaked paper and one nickel for example, is too small to light a bulb on its own, but it is still the same process that happens in a battery you buy at the store. We also learned that if we connect enough of the coin batteries together in the right way, we really can turn on a light bulb. It is the same thing that happens in a flashlight, and is especially like the battery in your mom or dad’s car.
Here is a project for those just beginning to learn about how batteries and electricity works: http://how-things-work-science-projects.com/battery-light-project/
First Grade Science Projects
Electricity is fascinating. It is also all around us. We wake by an alarm clock without thinking, then turn on a light and take a shower with hot water that we take for granted. Breakfast is cooked on an electric stove, or perhaps we selected frozen waffles that were kept that way by one use of electricity and warmed for eating by another. We plug in headphones to listen to our ipod on the way to work or school and the lightning bolt of a nearby thunderstorm may be just a mere distraction. It isn’t even something to think about it. It is just a part of our daily lives.
But what if we were to stop a moment and actually look at the world around us? Instead of just accepting that things “are” … could we figure out how things work instead? Could we capture interest long enough to bring a bit of wonder back into the normal everydayness of things? Bet we can, and that is exactly what this group of projects is all about. Given that the audience here is still quite young, most of these first grade science projects have been designed to be heavily supervised by the parent or teacher … but to be freely pondered upon by the young (or young at heart). Enjoy!
Turning on a Light Bulb
Come on – admit it. I know you’ve taken a flashlight apart, looked inside and tried to figure out why the light comes on when you push the button. I bet you’ve even looked at the bulb and wondered how that little thing can make so much light … right? Well, that is the objective here. This first grade science project is designed to help get young students wondering about how things work in the world around them, and then to answer some of those questions to keep them coming back for more. At the same time, it introduces a few concepts about electricity using everyday items they are already familiar with.
– 1 Standard size flashlight
– About 6 in. insulated wire, #12 or #18 works just fine
– 1 magnifying glass
– Small piece of sandpaper
– Pliers to make a loop in the wire (needle nose work best)
– Knife or wire pliers to remove insulation
This first grade science project requires very little setup. Simply remove the bulb and one battery from the flashlight and you’re ready to go. If you want to minimize the time spent setting up in class, you can also strip about 1 inch of insulation from each end of the wire. Make a loop on one end of the wire just big enough to hold the bulb (see photo).
Ask if any of the students have used a flashlight before. Almost every hand will probably go up, but let them give as many examples as they can of when they might need to use one. Then ask if anyone knows how a flashlight works. Chances are that nobody will raise their hand, so ask how many would like to learn, and let the fun begin.
You could break into a couple of first grade science project groups, but at this age, it is probably best to show them all in a single group and supervise while each that want to try can do so. Please be sure to set some project rules like the wire and battery are handled with care and only one person touches them at a time, etc.
If you have not stripped about 1 inch of insulation off each end of the wire and made a small loop in one of the ends with a pair of pliers, do so now. Bend the wire as shown in the above photo and place the bulb in the loop.
Either tape or hold the straight end of the wire on one end of the battery with your thumb and touch the end of the light bulb to the other end of the battery as shown in the next photo. The light should shine. If it doesn’t, either the wire on the battery or the wire on the light is not making a good connection. Use the small piece of sand paper to clean the wire ends … and try again. If you are making a connection (and you are sure the flashlight worked before taking it apart), the light will shine.
Give the students some time to try this first grade science project themselves. Then as a whole group, demonstrate how to make the light work again and ask them what they think will happen if you take either end of the wire or light off the battery. (Part of the purpose for any first grade science project is to make a prediction, then test to see if it holds true).
Take the end of the bulb off the battery. Does the light stay lit? No – it goes out. Tell them this is because an electric current only flows if there is no open space anywhere in our battery, wire and light. This is the same thing as saying current only flows in a complete circuit. When we break the circuit by taking one of the ends of the wire off the battery, (open space now), then current stops flowing and the light goes out.
Then take the bulb out of the wire loop and use the magnifying glass to show them the tiny filament of wire inside the light bulb.
After each has had a chance to see it, explain that when the current flows through that tiny wire, it gets very hot. As it gets hot it glows and that makes the light we see.
To shift the focus of this science project back to the flashlight itself, put the bulb and the battery back in the flashlight. When you turn it on and the light shines, tell them that the button or switch on the side is doing the exact same thing as we did when touched the wire end and the light to the two sides of the battery. The switch completes the electric circuit and current flows through that tiny wire in the light bulb called the filament. It gets hot, starts glowing and then lets off quite a bit of light for such a small object.
It is a bit early to discuss that the light bulb holds the filament in a vacuum so that it does not burn up as fast … but you can include that as well if time allows.
What just happened?
For the teacher – as discussed in Electricity Science Projects related to Charge, the battery provides a potential difference due to two disimiliar metals being immersed in a paste or fluid called an electrolyte. As chemical reactions at both the cathode (+ terminal) and the anode (- terminal) of the battery occur, ions flow through the electrolyte and electrons through the wire, as long as there is a complete circuit. (As an aside, fruit batteries like the lemon, apple or potato, as well as coin battery projects are great ways to focus on the battery itself).
In our experiment, if the light is not connected to one end of the battery and the wire end to the other, nothing happens because there is not a complete circuit for electrons to flow in, and therefore no current flows. When current does flow, the small filament inside the light bulb is a resistance in the circuit, and as current flows through it, it heats up. The type of wire used for the filament is specifically selected for the light it produces as well as how long it will work without burning out (which breaks the circuit and stops the current flow). To keep the filament from burning up too fast, the filament is also encased inside a container (usually glass), the air is pulled out of it and the resulting vacuum is sealed inside it during the manufacturing process.
For the students – as long as we have a complete circle for something called an electric current to flow around, the small wire inside the light bulb will glow. Whether we connect up the battery ourselves, or we put it all inside the plastic flashlight case, as soon as we make the complete circle (or circuit), the light will shine, at least for as long as the battery is good.
Summarize by answering the original question: Can we figure out how a flashlight works now?
And if you would rather try something a bit more “out of the box”, these might help …
Electricity For Kids And Grownups Alike!
The apple battery project is a second in a series of three fruit battery science projects for kids included on this site. It is an extension of the classic lemon battery project, and is also inexpensive, easy to set up and fairly easy to perform. In fact, with the firmness of the apple, it is easier to insert the terminals without having them touch.
If you look at the supplies photo below, you’ll see it is the same as the lemon battery project, except that we use an apple. For the same reasons noted in that experiment, a fruit battery isn’t powerful enough to light a bulb, so a voltmeter is needed to see what happens. As such, this is also listed this as a 5th grade science project, assuming it is performed by itself. However, if it is combined with the turning on a light bulb experiment, the student will better understand how meter movement relates to a bulb lighting up. If that is done, this can be used in electricity experiments, or elementary science projects from about the first grade on.
Time to Create an Apple Battery … Enjoy!
An apple battery only takes an apple, two nails and a piece of wire to demonstrate the concept. It’s a fun science project that helps show the way things work in a battery by using stuff we see around the house.
As with the lemon battery, we’ll learn a little more about electricity, and probably a few new science terms along the way. This is designed to be performed on its own, but if you elect to do the “Light Bulb” experiment at the same time, it will help connect what’s going on with the voltmeter reading to lighting the light bulb itself.
– 1 apple
– About 4 in. wire with insulation removed, #12 or #18 works just fine
– 1 steel nail, #6 or 8 works great
– 1 zinc plated nail, #6 or 8 is good
– Small piece of sand paper
– Knife or wire pliers to remove insulation (not shown)
– A voltmeter that can read tenths of a volt
The only preparation an apple battery project requires is to gather the materials, strip off the wire insulation and clean the ends of the nails and wire with the sand paper. (Gently on the zinc nail).
Since the lemon battery and apple battery share the same project steps, concepts and “how it works” explanation, I will not try to repeat it all here. Please refer to the lemon battery experiment if more details are needed on how to conduct the lab. Only a summary of the steps required follows here.
Split into groups as materials allow. If you are performing the light bulb project, demonstrate how the battery makes the flashlight bulb come on. Show them how the meter moves by touching the meter leads on the battery cell. Let them know if we can make the meter move using an apple instead of a battery, then the apple must be acting like a ‘real’ battery as well.
Choose any combination of nail and wire to start the experiment. These are the terminals for our battery. Insert the ends of the terminals into the apple a little over an inch deep. Get them as close as you can without touching each other. (If they touch, the battery will be ‘shorted’ and no voltage difference will show on the meter. If that happens, just pick a new spot on the apple and try again).
Select a DC setting on the voltmeter. Test it against an actual battery if you have one to make sure the meter is working properly. Swap the leads if you see a minus sign in the display, or take a minute to discuss polarity, and what the meter is telling you about which terminal is the cathode (+) and which is the anode (-). Using the meter on an actual battery (that has the + and – signs stamped on it) will provide the answer for them on this one.
Touch one of the meter leads to each of the terminals you inserted in the apple battery (steel and copper is shown here). Note the reading. Also note that the readings may vary from setup to setup, and from trial to trial. There are quite a few things going on that we cannot control, but the important point is that we do get a voltage reading.
Shift to another terminal combination. Zinc and steel are shown to the right. Again, note the voltage. Higher? Lower?
Try the final terminal set. As in the lemon battery project, you should see why zinc and copper make good terminals.
Show that if you hold the meter leads apart, touch them together, or even stick them directly in the apple themselves, nothing happens. The two dissimilar metals we used as battery terminals are needed, and they must be in the apple for the process to work. Otherwise we have no meter deflection and no apple battery.
Tell the group that the same thing causing the meter to move is what lights the bulb in a flashlight.
What just happened?
For the teacher – please see the lemon battery experiment for a complete explanation of what’s happening in the apple battery. The process and the concepts are identical. Additional information is also discussed in the Electricity Science Projects related to Charge section.
For the students – as long as we choose the right metals for our terminals, we can turn the apple into a battery.
Summarize by telling the group – the apple battery voltage is too small to light a bulb, but it is the same process that happens in a battery you buy at the store.
… And as in the other fruit battery projects, if you just need something you can pull off the shelf and do, these can sure help with that:
What else can be made into a battery? Find out here: http://how-things-work-science-projects.com/coin-battery-project/