StudySmarter - The all-in-one study app.
4.8 • +11k Ratings
More than 3 Million Downloads
Free
Americas
Europe
Lerne mit deinen Freunden und bleibe auf dem richtigen Kurs mit deinen persönlichen Lernstatistiken
Jetzt kostenlos anmeldenNie wieder prokastinieren mit unseren Lernerinnerungen.
Jetzt kostenlos anmeldenTo measure is to compare the magnitude of a physical property of an object or a system against a pattern or standard that can tell us its value. Measurements in everyday life include:
Units tell us the value of the physical quantity we are measuring.
The activity of measuring is done to an object to learn its properties (or physical quantity) and then compared against an accepted norm to obtain a value (the unit). See the example below:
You want to know the weight of a parcel. The weight is the physical quantity of the parcel. You need to compare this against a unit of measurement to know its value. The unit varies depending on the unit system you are using.
There are several different unit systems. The most universally accepted unit system is the International System of Units (SI). Other unit systems are the United States Customary System and the Imperial system.
Measurements using different systems can deliver different values, as they measure the same physical quantities using different units. An example of this is the definition of temperature for the Imperial system, which uses Fahrenheit.
The freezing temperature of water is 273.15 Kelvin in the SI and 32 F in the Imperial system.
Generally speaking, there are two methods for measurements: one is by reference, while the other uses formal units.
The principle is simple: you take an object, and you use that object as a reference to measure a quantity.
An everyday example is using a spoon to measure sugar for your coffee. However, you can see the problem with this – spoons come in different sizes, and you could also be adding more sugar depending on how much you fill the spoon.
This method involves using a standard so you can reproduce the measurement every time you need it.
Let’s say that you need 10 grams of sugar. You will need a scale, but now you can measure exactly 10 grams of sugar every time. You can add and remove sugar to get the correct measurement and reproduce this whenever you want a coffee.
The ability to reproduce values using an instrument as a reference is why unit systems are important in measurement.
Accuracy is important when taking measurements. To achieve it, you should follow these instructions:
When you measure the time it takes for a pendulum to make a complete oscillation, if you use a timer, the time measured will depend on your reaction time. In this case, several measurements are necessary so you can calculate a more precise average value.
To graphically represent your measurements in real life, you can use a plot. Plots are drawings that use ‘x’ and ‘y’ variables to relate the change of one value to another. To put it simply, a plot is the graphical relationship of two or more variables. Usually, x is named as the independent variable, and y is the dependent variable.
See the example of a plot below, representing how a pendulum's movement decays over time.
The variable ‘x’ represents the measurement. The first point is the first measurement, where it takes 2 seconds for the pendulum to come and go. After the first measured value x1, you take a second measurement x2, then x3, x4 and so on.
The second point is the second measurement x2. The pendulum moves less until it slowly comes to a stop. The marks on the plot show the values decaying over time.
Measurements are the values obtained after comparing a physical property to a pattern or standard that can tell us their value.
To measure something means to compare the magnitude or value of a physical quantity against a pattern or unit of measurement.
We can measure by reference, compare to other objects, or measure by using formal units.
Units are an agreed standard, a value used as a reference to measure. An example of such standards are the SI units kilogram, metre, second, candela, etc.
Flashcards in Measurements16
Start learningWhat do we measure in an object?
We measure a physical quantity or property.
We need units when doing measurements. True or false?
True.
What is the advantage of using units when measuring?
It allows us to reproduce measurements.
How can we graphically represent measurements?
We can represent measurements using a plot.
When measuring with a scale, we need to set the scale to 0 every time. True or false?
True.
What is the name of the error when we are not careful reading a value using marks on the instrument?
Parallax error.
Already have an account? Log in
Open in AppThe first learning app that truly has everything you need to ace your exams in one place
Sign up to highlight and take notes. It’s 100% free.
Save explanations to your personalised space and access them anytime, anywhere!
Sign up with Email Sign up with AppleBy signing up, you agree to the Terms and Conditions and the Privacy Policy of StudySmarter.
Already have an account? Log in