Drawing and Interpreting Graphs in Science — Answers
Answer sheet with model answers and success criteria for the 7th Grade working scientifically worksheet.
Success TutoringWorksheetsAnswer sheet7th Grade · Science · Working ScientificallyDrawing and Interpreting Graphs in Science — Answers
Part A: Choosing and setting up a graph
Read the passage, then answer the questions.
Use a line graph when both variables are numbers measured on a continuous scale, such as time, temperature or length. Use a column graph when the independent variable is made of separate categories, such as types of material or habitats.
Put the independent variable (the one you change) on the horizontal x-axis and the dependent variable (the one you measure) on the vertical y-axis. Label each axis with the variable and its units, choose a scale that goes up in equal steps and uses most of the grid, and give the graph a title.
- Aline graph
- Bcolumn graph
- Cpie chart
- Dpicture graph
Answer: line graph
Time and temperature are both continuous (measured) variables, so a line graph shows the change best.
- Aline graph
- Bcolumn graph
- Cscatter graph with a line
- Dno graph is possible
Answer: column graph
The habitats are categories, not numbers on a scale, so a column graph is best.
- Athe horizontal (x) axis
- Bthe vertical (y) axis
- Ceither axis — it does not matter
- Dit should not be graphed
Answer: the horizontal (x) axis
By convention the variable you change goes along the horizontal axis and the variable you measure goes up the vertical axis.
- trend
- outlier
- interpolate
- extrapolate
- line of best fit
- a result that does not fit the pattern
- read a value between your measured points
- extend the pattern beyond your measured points
- the general pattern shown by the data
- a smooth line or curve that follows the overall pattern of the points
Answer: trend → the general pattern shown by the data; outlier → a result that does not fit the pattern; interpolate → read a value between your measured points; extrapolate → extend the pattern beyond your measured points; line of best fit → a smooth line or curve that follows the overall pattern of the points
Answer: units
Part B: Interpreting a cooling curve
Imagine the data plotted as a line graph. Show your working.
Investigation: A beaker of hot water was left to cool in a room at 22 °C. Its temperature was recorded every 2 minutes.
Time (min): 0, 2, 4, 6, 8, 10
Temperature (°C): 80, 64, 52, 43, 37, 33
Answer: 16 °C; 8 °C per minute
- 80 − 64 = 16 °C
- 16 ÷ 2 = 8 °C per minute
Answer: 47 °C
- 80 − 33 = 47 °C
Answer: About 47 °C (accept 46–48 °C): between 52 °C at 4 min and 43 °C at 6 min, slightly below the halfway value of 47.5 °C because the curve is flattening.
Answer: The temperature decreases over time. It falls quickly at first and then more and more slowly as the water gets closer to room temperature.
- A0 °C
- Babout 22 °C (room temperature)
- C33 °C
- Dit would keep falling forever
Answer: about 22 °C (room temperature)
Hot water cools until it reaches the temperature of its surroundings, then stops changing. Extrapolating too far without this knowledge could give a wrong answer.
Part C: Good graphing practice
Write True or False, then answer the extended question.
Answer: True
Unequal steps distort the shape of the graph and make the trend misleading.
Answer: False
When points are scattered, draw a smooth line of best fit through the overall pattern instead of joining dot to dot.
Answer: True
An outlier may be caused by an error, so scientists check it rather than ignoring it or hiding it.
Model answer: 1. The axes are the wrong way round: time (the independent variable) should be on the horizontal axis and temperature on the vertical axis. 2. There are no labels or units: label the axes "Time (min)" and "Temperature (°C)". 3. The scale is uneven: use equal steps, such as 0, 10, 20 … 90 °C. 4. There is no title: add one such as "Temperature of hot water as it cools over 10 minutes". 5. Large blobs are inaccurate: plot small, neat crosses and draw a smooth curve of best fit through them.
Success criteria:
- Identifies the swapped axes
- Identifies missing labels/units
- Identifies the uneven scale
- Identifies missing title or poor plotting
- Gives a correct fix for each problem
Marking tips
- Give credit for correct method even when the final answer slips — the working shows where the thinking went right.
- For open-ended tasks, use the success criteria as a checklist rather than looking for one "right" answer.
- Celebrate what went well first, then pick one thing to work on next.
Great work. Here's what to try next: