We think that the lemon will work better as a battery. The acid inside potatoes and lemons makes a chemical reaction. Acids taste sour and if you are weird like us, you know a lemon is very sour. A potato, on the other hand, has a bitter taste. If you were listening at school you know that a bse tastes bitter and an acid tastes sour. We found out through our research that acid is more conductive than a base. That's why we think a lemon is an acid and will conduct electricity better than a potato and work better as a battery.

Potato:

The potato battery is an electrochemical battery. Different metals such as zinc and copper have a chemical reaction with the acids inside of the potato. A chemical reaction such as this can create just enough electric energy to power a mini device such as the motor we are using.

Sources:

 https://stemgeneration.org/potato-power/

https://www.science-sparks.com/how-to-make-a-potato-battery/#:~:text=Potato%20Battery%20Instructions,using%20wires%20and%20crocodile%20clips.

https://www.youtube.com/watch?v=XsuYTL1kvsI  how to make a simple fan

Lemon:

The source of electric energy is the copper and zinc pieces in the citric acid of the lemon. The acid of the lemon with the zinc in the nail loosens the electrons in the lemon. The copper pieces have a stronger pull to them so the loose electrons in the lemon will get pulled toward the copper when the electrodes are connected ny wires. The moving electrons is called an “electric current” which is what powers the motor we are using. 

Source: https://www.scienceworld.ca/resource/lemon-battery/

Controlled Variables: alligator clips, windmill fan, motor, timer, time of day, environment, potatoes used, lemons used, wires, pennies, nails.

Manipulated Variables: amount of potato and lemon batteries.

Responding Variables: the number of rotations of the fan, the amount of power provided by the potato and the lemon.

Procedure - Potato & Lemon Battery

Potato Battery

1. Insert one nail about 1 inch into the potato end. Make sure not to poke all the way through the potato. Use a pen to write a minus sign “-” next to the nail
2. Push one penny into the opposite end of the potato. Make sure most of the penny is still sticking out. Use a pen to write a plus sign “+” next to the penny.
3. Attach the wires to the potato and then to the fan motor.

Lemon Battery

1. Roll a lemon between your hands to loosen up the juice on the inside.
2. Carefully make two slits in each lemon with a knife.
3. Place a copper coin and either a silver coin or a galvanized nail into each lemon.
4. Attach the lemons to each other using wires and crocodile clips. The copper of one lemon should attach to the zinc of another lemon to work.

1. Cut the top off the bottle with an exacto knife.
2. Cut around the top the make it even with scissors.
3. Cut out a cardboard base.
4. Glue a toilet paper roll to the base.
5. Cut the bottle top into 4 or 5 sections to make the fan blades.
6. Mark 1 fan blade to count rotations.
7. Make a hole in the bottle cap and attach motor with wires.
8. When ready to conduct test hook up wires to lemon or potato

we realized that lemons and potatoes do not work well as power sources we tried cutting the lemons in half and cutting the potatoes in half we tried boiling the potatoes we tried substituting pennies for thin copper wire and then new thick copper wire, we tried putting the lemons and the potatoes on paper towel and then tin foil. We also tried buying two new motors and an L-E-D light bulb and then we ordered a whole new not used pack, we tried switching out the lemons and the potatoes and we tried getting new alligator clips but no matter what we tried the motor wouldn't spin and the light bulb would not turn on.  

the lemons and potaoes were different sizes, will that matter? 

What if we cut them in 2? 

 

In the end, we learned that potatoes and lemons are not the most convenient power sources. We thought the lemons would work better, but after testing both lemons and potatoes we found out that neither of them work. Even when we tried many different ideas to try and fix the issue, we still could not get a consistent current to power the fan.

Maybe if we had more wiring and more lemons and potatoes etc we could get the fan blades to rotate.

Can we use natural objects as power sources? is this a sustainable option?

Our world may run out of sources of energy and power. It could be important to explore other options.

It is hard to control all of the variables in the experiment. the amount of power created might not be enough to really make the fan work properly. the potatoes probably don't contan the same amounts of starch. the lemons are not all exactly the same.

Used many websites
Science World
Stem Generation
Science Sparks 
UTube - how to make a fan
Smithsonian magazine
 

Thanks to the Parents of Alex and Dyllan also to Alex's Nan and Gigi and our neighbour Josh who is an electrician.  Olympic heights Grade 5 6 teachers