Drawing conclusions from evidence (age 12+) · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

Conclusions that use the numbers

Science · Scientific Inquiry · ages 12-13
Name ______________________   Date ____________

  1. Look at the chart. What happens to reaction time as caffeine dose increases?

    0mg0.3250mg0.27100mg0.21
    • It decreases
    • It increases
    • It stays the same

  2. A kitchen scale always reads 5 g too high, in every single measurement. What type of error is this?

    • Random error
    • Not an error
    • Systematic error

  3. Which sentence is a strong evidence-based conclusion?

    • The experiment went well.
    • My hypothesis was supported: dissolve time fell from 42 s to 15 s as temperature rose.
    • I think the tablet dissolved because of the water.

  4. Maya measured the temperature of a cup of hot water every minute as it cooled. She wants to find out whether there is a relationship between time and temperature. What should she do first to look for a pattern in her data?

    • Make a scatter graph of her measurements
    • Calculate the mean of all the temperatures
    • Write her final conclusion right away
    • Repeat the whole experiment five more times

  5. Dissolve time was 42 s at 20°C and 15 s at 50°C. By how many seconds did dissolve time decrease?

    20°C4250°C15

    Answer: ______________

  6. A hypothesis predicted taller plants with more sunlight. Data: 4 hours of sun gave 22 cm tall plants, 8 hours gave 39 cm. Which conclusion best uses this evidence?

    4 hours228 hours39
    • The hypothesis was supported: height rose from 22 cm to 39 cm as sunlight increased from 4 to 8 hours.
    • Plants grew because of water.
    • Sunlight probably helped a little.

  7. Liam plots his plant growth data on a scatter graph. The points start low on the left and climb steadily upward to the right, staying close to one straight line. What does this pattern tell him?

    • The plants grew taller as time passed, in a fairly steady way
    • The plants stopped growing after the first week
    • There is no relationship between time and height
    • One plant grew and all the others shrank

  8. A random error can be fixed by recalibrating an instrument.

    Circle one:   True   False

  9. Timed trials gave slightly different results each time because the tester started the stopwatch by hand. What is the BEST specific improvement?

    • Do more repeats
    • Use a stopwatch triggered automatically by a sensor
    • Round the numbers

  10. A hypothesis predicted more fertilizer increases plant height. Data: 0 g gave 10 cm, 20 g gave 27 cm. Which conclusion correctly uses this evidence?

    0g1020g27
    • The hypothesis was supported: height rose from 10 cm to 40 cm.
    • The plants grew taller, so the hypothesis is probably right.
    • The hypothesis was supported: height rose from 10 cm to 27 cm as fertilizer went from 0 g to 20 g.
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Answer key

For grown-ups. Fold this page away before handing over the rest.

Conclusions that use the numbers W1-mt_3jmBpEepYX-s1

  1. It decreases · Reaction time drops from 0.32 s to 0.21 s as the dose rises, so it decreases.
  2. Systematic error · It shifts every reading in the same direction, so it is systematic.
  3. My hypothesis was supported: dissolve time fell from 42 s to 15 s as temperature rose. · A strong conclusion names the hypothesis, whether it was supported, and gives the actual numbers.
  4. Make a scatter graph of her measurements · Before you can describe a pattern, you need to see the data. A scatter graph puts each pair of measurements (time and temperature) on a grid so any trend becomes visible.
  5. 27 · 42 minus 15 equals 27 seconds.
  6. The hypothesis was supported: height rose from 22 cm to 39 cm as sunlight increased from 4 to 8 hours. · This conclusion names the hypothesis, says it was supported, and gives the exact numbers from the data.
  7. The plants grew taller as time passed, in a fairly steady way · Points that rise from lower left to upper right show a positive trend: as one quantity increases, the other increases too. Points close to a straight line mean the change was steady.
  8. False · Recalibrating fixes systematic errors. Random errors need better technique or a more precise tool, like an electronic timer.
  9. Use a stopwatch triggered automatically by a sensor · Naming the exact cause, hand-timing, and fixing it directly targets the random error, unlike a vague 'do more repeats.'
  10. The hypothesis was supported: height rose from 10 cm to 27 cm as fertilizer went from 0 g to 20 g. · Only "The hypothesis was supported: height rose from 10 cm to 27 cm as fertilizer went from 0 g to 20 g" quotes the real numbers from the data, 10 cm to 27 cm, while stating whether the hypothesis was supported.
Worksheet · LightMySky