uncertainty worksheet
To calculate the average=Add all measurements and divide by the number of measurements
Average=Sum of all measurements/ number of measurements
To calculate the absolute uncertainty of the average=(Highest measurement -Lowest measurements)/2. This is called (Range/2)
I also have an answer key but Im not sure if its right i want 100% accurate answers with steps. I’ll attach the answer key as well once we chat.
UNCERTAINTY WORKSHEET
1. In the diagram at right, 4 targets are shown.
If the goal is to hit the centre of the bulls-eye,
a) Which show a precise aim?
b) Which show an accurate aim?
E
x
p
~
2. a) Calculate the average and the uncertainty for each set of data:
AVG
UNCERT.
SET A: 15.32, 15.37, 15.33, 15.38, 15.35
SET B: 16.30, 16.19; 16.24 16.29, 16.23
b) The “true” value that we were attempting to measure was: 16.26
Which set of data is most precise? _______ Which was most accurate? _______
3. In which of the following examples would the precision of a thermometer be more important
than its accuracy?
a) Determining, the identity of an unknown compound by comparison of its measured melting
point to a reference table
b) Measuring the temperature change when a chemical is added to water
4. In an experiment, you are measuring the mass of water by difference. You use 2 different balances to
measure mass, and your data looks like this:
Balance A
Balance B
Avg. with uncertainty
Empty Beaker
207.2 g
210.4 g
__________________
Beaker + 50mL water
257.2 g
260.4 g
__________________
50 mL water alone
__________
_________
__________________
Complete the table. Do you think your main source of error is random or systematic? If you believe one of
the balances is off, how would you determine which one? What happens to your uncertainty after you’ve
done the calculations? WHY?
5. In an experiment, you are measuring the mass of water by difference. You use only one balance, but
ask 2 friends to help you make measurements. Your data looks like this:
Empty Beaker
Beaker + 50mL water
50 mL water alone
You
207.2 g
257.3 g
________
Friend A
207.1 g
257.0 g
________
Friend B
207.3 g
257.5 g
________
Avg. with uncertainty
__________________
__________________
__________________
Complete the table.
Might random error be present? What is causing it? If so, how would you correct for it?
Might systematic error be present? What is causing it? How would you find out?
6. Use the following scales to measure the quantities required. Be sure to list the appropriate number of
digits, as well as the uncertainty that goes along with each measurement
GRADUATED CYLINDER (mL):
BEAKER (mL):
V = ______________
V = ______________
BURET(mL):
V = ______________
BALANCE (g):
M = ____________
7- You need to measure the length of the table. You can use a metre stick or a 30-cm ruler. Both have the
smallest division at 0.5 cm. Will one of the instruments give a greater uncertainty? Explain.
