Level 1 Physical Science: Linear Relationships Flashcards
What is a variable
Things that you can change during an investigation.
What are the 3 main variables
1) Independent variable
2) Dependent variable
3) Controlled variable
What is a Independent variable (IMPORTANT)
This is the variable that you choose to change within a set range of values, for example changing the distance measured
What is a dependent variable (IMPORTANT)
This variable ‘depends’ on the independent variable. For example, the time it takes to run different distances
What is a controlled variable (IMPORTANT)
These are all the other possible things that could change in an investigation but you are not testing. These need to be controlled, i.e. not change during the experiment. For example, in the above examples (distances, and time taken to run those distances) controlled variables would be the person running, where they are running, the shoes they wear, the weather conditions.
What is the independent variable for the investigation: the relationship between force on a spring and how far the spring extends
Independent variable= Force on the spring
What is the dependent variable for the investigation: the relationship between force on a spring and how far the spring extends
Dependent variable= extension of the spring
What are the control variables for the investigation: the relationship between force on a spring and how far the spring extends
The spring used, ruler used to measure, where the extension is measured from.
What is the independent variable for the investigation: the relationship between the drop height of a ball and the height it bounces back up to
the drop height of the ball
What is the dependent variable for the investigation: the relationship between the drop height of a ball and the height it bounces back up to
the bounce back height
What are the control variables for the investigation: the relationship between the drop height of a ball and the height it bounces back up to
the person dropping, the ball, the ball used, the place the ball is dropped
Ethan was told by his teacher to find the relationship between the mass of a ball and how high it can bounce. What is the independent variable
Mass of ball
How many different variables do we need to do in our investigation
At least 5
To measure mass what would the equipment be and what are the units
Electronic scales. Units= Kilograms, kg or Grams, g
To measure distance what would the equipment be and what are the units
Ruler or metre ruler. Units= Millimetres, mm or Centimetres, cm or Metres, m
To measure temperature what would the equipment be and what are the units
Thermometer. Units= Degrees Celsius, °C
To measure Time what would the equipment be and what are the units
Stopwatch. Units= Seconds, s
To increase the accuracy of your measurements, you should repeat (do trials of) your measurements ____ times. And then average them.
To increase the accuracy of your measurements you should repeat (do 3 trials of) your measurements 3 times. And then average them.
How many variables do you need to do and how many times do you measure each one? (repeats/trials)
You must do at least 5 variables and repeat each one 3 times.
What are the 2 errors you need to be aware of that can affect your accuracy of your measurements
1) Zero error
2) Parallax error
What is Zero error
Some measuring equipment (such as rulers) does not start at zero when it should. We call this ZERO ERROR. You need to check for this before using your equipment.
What is Parallax error
If you look at a measurement from above or below the reading you will get the wrong value. You must take measurements at EYE LEVEL to avoid this error.
What are the 9 rules for drawing a straight line graph
1) Use a RULER
2) Your graph should take up at least HALF A PAGE
3) The INDEPENDENT VARIABLE goes on the X AXIS (horizontal axis)
4) The DEPENDENT VARIABLE goes on the Y AXIS (vertical axis)
5) The SCALE on any axis must be EVEN ie. It goes up in even intervals eg 0,2,4
6) Plot POINTS with a CROSS
7) LABEL each axis with the VARIABLE AND ITS UNIT
8) Draw a LINE OF BEST FIT through our points (this is not join the dots but draw a line to show the general shape of the points).
9) Give the graph a TITLE that has both the INDEPENDENT AND DEPENDENT VARIABLE in it.
What axis on the graph does the independent variable go on
The x axis (horizontal axis)
What axis on the graph does the dependent variable go on
The y axis (vertical axis)
What is very important for working out the relationship between the independent and dependent variables
The steepness of a straight line graph you have drawn is very important when working out the relationship between the independent and dependent variable you are investigating.