watermelon electrical characteristics

We don't do homework here. You have to do your own homework. If, after you've done the research and made an attempt to perform the measurements yourself, you need help, come on back.

Do a little research!

With a multimeter and a little bit of melancholy!

Sorry, we don't answer homework questions here. Have a look in your library at a basic (or elementary) chemistry book, they generally have the information and test procedures on measuring electrical properties of vegetables and fruit (such as lemons) that you require.

It can not be a homework

He is asking for current, resistance,conductivity and voltage.

Sorry for not telling you what i did. I actually took unripe,ripe and overripe samples of watermelon and blended them into juice. I took each sample and tried to measure the voltage and current through it with a multimeter and a 9v battery as the source but the values were fluctuating and the distance actually varied when moved from the wire in the electrolyte. So i have actually tried something. I checked for people who have carried out research on it but i found none. I am to submit something in the next 3 weeks.

Bravo. You've just learnt something new today: conductivity and resistance vary with distance. The best solution to this problem would be to create a fixture of some sort so that the distance between your 2 probe tips remains fixed so that you'll get more or less consistent readings. Set the 2 probe tips at a distance of 1cm preferably, as conductivity and resistance are measured on a per cm rate. That way you can just take the reading directly.

The resistivity will widely vary and there is no doubt about it. The vaariation is likely to be so high that you are unlikely to have any significant result to show.

However as DVader told take a fixture dip it to same depth or take 2 cu plates. Space them and hang them by nonconducting (say plastic) rods. Connect two insulated wires to it (it will take almost the effect of the dip depth)

Then just use multimeter on Ω mode and measure resistivity.

Similarly with the Cell+ammeter you can measure the current.

I feel there will be a difference in the R (direct measurement) and V/I due to presence of ions.

Also you can have dissimilar plates and find out the EMF generated by putting the Multimeter on V mode.

But still variation will be too high.

These things you should have posted in the Education or Projects forum.

Yabut if he writes this down, as clearly and in an organized manner as he can. he's well on his way to scientific methodolgy. The experiment can fail, but not the knowledge gained in trying.