Power Failure

Students will need the worksheet for this activity

Equipment list

Per group (recommended 2-3 per group)

3 Pieces of fresh fruit (variety of seasonal fruit can include apples, potatoes, lemons, oranges, strawberries etc.)

4 Alligator clips. These can be purchased from Jaycar 

3 pieces of copper (1c and 2c coins work well, copper strips also work well, if these are difficult to source copper tape can work, but requires folding to make multiple layers to increase thickness)

3 pieces of iron (screws work well for this)

LED (superbright LED works well, standard LEDs can be a little faint, these are available at stores such as Jaycar) or you can use an electric circuits globe

Wipes/paper towel to clean up any fruit juice that leaks from the pieces

Recommended -  Multimeter or voltmeter to measure the volts being produced by the fruit battery (you can skip this and just compare the brightness of the LED if you don't have access to a multimeter)

The teacher may also need a knife to cut slits in the fruit pieces. 

Preparation (shopping for fresh fruit prior to the day, minimal set up required on the day)

Shop for fresh fruit prior to the activity to ensure best results

We recommend making sets of equipment (iron, copper, leads and LED) for faster distribution on the day. 

Additional Information 

Students need to connect the pieces of fruit into a circuit as per photo on the worksheet. 

If the LED is not working it could be backwards so ensure the negative (short lead) is closest to the screw and the long lead is closest to the copper. Also make sure that the leads are connected and that the metal (copper and iron) are in contact with the juice from the fruit, they may need a wriggle to connect properly. 

The LED can be very faint, so students may need to cup their hands around the light if the room is quite bright. 

(add electrochemical cell diagram)

Once the students get the circuit working sign the sheet and get them to experiment with combinations of different fruit/veg and find out what gives them the best output. This can be measured using the multimeter, or if you haven't got access to a multimeter it can be measured subjectively using the brightness of the light. 

Students draw the circuit - this can be using the fruit and coins or they can attempt to use the symbols to draw their circuit