If you can’t get your hands on a scale, get your ass in the kitchen and grab one of those glass spice jars that usually sit on a rack with all sorts of other spices. Dump out the contents and fill the 3” spice Jar about a third full with water.
As it would be nice to have a digital scale on you at all times, the vibrator takes precedence in an overstuffed purse. Anyways, proper ratio’s can never be stressed upon enough in the RP/I/E rxn so let the ratio’s begin.
Get a cigar size test tube and place it in the spice jar with the water and make sure that the test tube is floating above the bottom of the jar and that the water level is not about to spill out the top. Get a ruler of any kind and measure the depth of the water in the jar.
Next put your E inside the testube and measure the new depth of the water as it sits in the spice jar. Mark that measurement against the first measurement. Remove your E and replace with I2, adding just enough to match the water level measurement you took for the E.
You should now have enough data to calculate your RP. Your first measurement was the weight of the test tube as it displaced water at a certain level in the jar. Subtract the two measurements taken and divide by 3 for your third RP calculation. Of course make sure you have removed the I2 before weighing.
So how about calibration? Remove the RP and place in the test tube a u.s nickel. Five pennies won’t do. Mark that measurement against the others. It displaces approximately ½” of water on my spice jar. Anyways that measurement is appox equivalent to 5 grams. Elementary, but better than eyeball for sure.
HS