Function

Hello everyone!

For a dissertation for biology, I've decided to perform a water quality test (apart from the usual biotic life; micro-invertebrats etc.).

I'd like to know if there's a way to indicate (and the amount of; just indicating the presence won't give us information on the quality of the water...):

• Phosphate
• Ammonium
• Nitrate
• Nitrite
• Concentration of dissolved oxygen

Thanks!

Small question in order to help you: what's the meaning of "0.168M"?

a) scale, grams

b) scale, kilograms (use density of water, substract glass mass)

c) Google Maps (don't know; what's "here"?), a car, perhaps, after resetting your kilometers counter?, kilometers

d) scale, grams

e) ok, now this is a bit more complicated: fill a glass (perfect cilinder, of which height and radius are known) with water. Calculate the volume of the water. Drop the pebble in the water, and recalculate the volume of the 'water'. Substract original volume of new volume, and you have the volume of the pebble. Weigh the pebble, using a scale, and use the mass and volume to calculate density.

f) can't measure it with equipment, for the earth is not supported. You could base yourself on the formula for gravitational force (g):

[math]g=G\cdot\frac{m}{r^2}[/math] with m = mass of the earth, r = radius of the earth and G = gravitational constant, approx. [math]6.67\cdot 10^{-11} \frac{m^3}{kg\cdot s^2}[/math] and g = approx. [math]9.81\frac{m}{s^2}[/math] and r = approx. 6.371 km. Just isolate m out of the formula, and you have the mass of the earth. Express result in kilograms or megaton, gigaton, whatever you prefer.