Physics Lab 1 Jessica Oppenlaender
Preliminary Questions: Measurements
1. What methods are called Direct and Indirect Methods?
Direct method is a technique for measurements that uses measuring devices to get the
measurements. Indirect method is a technique that cannot be measured with a device but instead
must be calculated and derived from other indirect and direct measurements.
2. What is meant by Accuracy, Precision and Uncertainty?
Accuracy refers to the ability of a measurement to match its calculated quantity to its actual
quantity. Precision refers to the ability of a repetition among a series of measurements.
Uncertainty means that a single measurements certainty is limited by precision and accuracy of
the measuring instruments along with other factors that may affect the experiments ability to
make proper measurements.
3. Name three types of uncertainties?
1) Instrumental - Uncertainty of instruments precision. This is because all instruments have
fixed precisions which limit the ability to resolve small difference in measurements.
2) Statistical- Statistical values are estimated values or percentages. These values can differ
from the true value.
3) Systematic- These are known uncertainties that are connected to observations that are being
made. Examples of these can be human and knowledge limitations.
4. What errors does one consider as systematical errors?
Errors that are considered systematical are failure to calibrate an instrument, instrument drift, lag
time and failure to account for factors.
5. What uncertainty usually describes the systematical error?
Instrumental uncertainty usually describes the systematical error.
6. What errors does one consider as statistical errors? What is the reason for statistical uncertainties?
Errors in individual measurement can be considered statistical. For example while measuring
with certain instruments you are only able to measure up to the values given. When you measure
with only these values it leaves room for errors and these types of errors. These values will vary
from measurement to measurement because of experimental conditions that cannot be controlled.
7. How can one estimate errors caused by rough experiment?
Rough experiment errors can be estimated by using indirect measurements.
8. How does one determine an absolute uncertainty for Direct/Indirect method?
Indirect – √
Direct – √ Physics Lab 1 Jessica Oppenlaender
9. Give definitions of;
Significant Figures – A method to express error in measurement
Scientific Notation – A method to write numbers that are very small and/or very big more
conveniently. They are written in the form “A x 10 “, which means A times 10 to the power of
Units – A physical quantity that is used to compare quantities of the same kind to express their
10. How do you compare Measured Values?
Measured values are compared using the equation
11. How do you compare Measured and Theoretical Values?
Measured and Theoretical Values are compared using the equation
12. What is the lab purpose?
The purpose of this lab is to examine regular and irregular shaped objects and apply different
experiments to them to determine certain physical properties. With the results of the different
experiments we will be able to compare them and be able to