practical investigation - uncertainty

[S_L1003]

Hi! Could somebody please explain how to figure out uncertainty in a prac? I am doing an experiment on sound vibration in a tube to find the speed of sound, and this is my method:
1.   Record the temperature of the surroundings
2.   Arrange the water reservoir and fill the tube with water so that it is possible to change the water level in the tube. Add food dye to make water clearly visible. Bring the water level up to the highest point possible to begin.
3.   Strike the tuning fork and hold it above the tube so that the sound travels into the cylinder
4.   Have one person slowly lower the water level using the water reservoir, while their partner listens for an amplification in the tone. Once identified, move the water level up and down to locate exactly where the point of maximum tone occurs.
5.   Once identified, take a measurement with the tape measure from the bottom of the meniscus, taking 4 measurements
6.   Keep lowering the water to find the next resonant length at 3λ/4. Move the water level up and down several times to locate the exact point of maximum volume, taking the measurement with the tape measure from the bottom of the meniscus. Take 4 measurements.
7.   Repeat this with the remaining three tuning forks.

I also don't know how to define the independent and dependent variables
Thanks

[Bri MT]

Hey!

Remember that your independent variables are being manipulated to examine the impact on the dependent variable

Here's some hints to help you out:
- You are changing your IV when you repeat the experiment for a new ___
- You are measuring what the DV is as a result of that change

For uncertainty consider how precise the measurements on your tape measure are. For analogue instruments, half of the distance between markings is used.


I hope this helps and please follow up with further questions if unsure