Science: Reading Data Tables and Drawing Evidence-Based Conclusions
Using patterns, comparisons, and evidence to support scientific claims
Science: Reading Data Tables and Drawing Evidence-Based Conclusions
Using patterns, comparisons, and evidence to support scientific claims
Science - Grade 9-12
- 1
A student measured the rate of photosynthesis at different light intensities. Data: light intensity 100 lux, rate 4 bubbles per minute; 300 lux, rate 9 bubbles per minute; 500 lux, rate 14 bubbles per minute; 700 lux, rate 17 bubbles per minute; 900 lux, rate 18 bubbles per minute. Write an evidence-based conclusion about how light intensity affects photosynthesis.
Look for both the overall trend and where the pattern changes.
The data show that photosynthesis increases as light intensity increases, but the rate begins to level off at higher intensities. The rate rises from 4 bubbles per minute at 100 lux to 17 bubbles per minute at 700 lux, but it only increases to 18 bubbles per minute at 900 lux, suggesting another factor may be limiting photosynthesis. - 2
A class tested how soil pH affects seed germination. Data: pH 4.5, 22 percent germination; pH 5.5, 58 percent germination; pH 6.5, 86 percent germination; pH 7.5, 80 percent germination; pH 8.5, 49 percent germination. Which pH range appears best for germination, and what evidence supports your answer?
The best pH range for germination appears to be near neutral, especially between pH 6.5 and 7.5. The evidence is that germination was highest at pH 6.5 with 86 percent and remained high at pH 7.5 with 80 percent, while more acidic and more basic soils had lower germination rates. - 3
Four metal samples were measured to calculate density. Data: Sample A, mass 27 g, volume 10 mL; Sample B, mass 54 g, volume 20 mL; Sample C, mass 39 g, volume 15 mL; Sample D, mass 80 g, volume 40 mL. Which samples are likely made of the same material, and why?
Use density = mass divided by volume for each sample.
Samples A and B are likely made of the same material because they both have a density of 2.7 g/mL. Sample A has 27 g divided by 10 mL, and Sample B has 54 g divided by 20 mL. Sample C has a density of 2.6 g/mL, and Sample D has a density of 2.0 g/mL, so they are less likely to be the same material as A and B. - 4
An enzyme experiment produced these results. Data: 10 degrees C, reaction rate 12 units per minute; 20 degrees C, 25 units per minute; 30 degrees C, 42 units per minute; 40 degrees C, 55 units per minute; 50 degrees C, 20 units per minute; 60 degrees C, 3 units per minute. Identify the enzyme's approximate optimal temperature and explain your reasoning.
The optimum is where the measured rate is greatest, not where the temperature is greatest.
The enzyme's approximate optimal temperature is 40 degrees C because the reaction rate is highest there at 55 units per minute. The rate increases from 10 degrees C to 40 degrees C, then drops sharply at 50 degrees C and 60 degrees C, which suggests the enzyme becomes less effective at higher temperatures. - 5
Scientists sampled three stream sites. Data: Site A, upstream forest, turbidity 5 NTU, dissolved oxygen 8.2 mg/L, fish species 12; Site B, near construction, turbidity 42 NTU, dissolved oxygen 5.1 mg/L, fish species 4; Site C, restored wetland, turbidity 11 NTU, dissolved oxygen 7.5 mg/L, fish species 10. Write a conclusion about water quality and fish diversity using evidence from the table.
The data suggest that better water quality is associated with higher fish diversity. Site A had low turbidity, high dissolved oxygen, and 12 fish species, while Site B had much higher turbidity, lower dissolved oxygen, and only 4 fish species. Site C had improved water quality compared with Site B and also had more fish species. - 6
A reaction was tested at different reactant concentrations. Data: 0.10 M, average reaction time 120 seconds; 0.20 M, 61 seconds; 0.40 M, 30 seconds; 0.80 M, 15 seconds. Describe the relationship between concentration and reaction time.
In this table, a shorter reaction time means the reaction happened faster.
As reactant concentration increases, reaction time decreases. The data show that doubling the concentration from 0.10 M to 0.20 M reduces the time from 120 seconds to 61 seconds, and increasing the concentration to 0.80 M reduces the time to 15 seconds. - 7
A student tested which cup covering reduced heat loss the most. All cups started at 70 degrees C. Data after 30 minutes: no covering, 42 degrees C; cotton cover, 51 degrees C; wool cover, 57 degrees C; aluminum foil cover, 53 degrees C; foam cover, 62 degrees C. Which covering was the best insulator, and what evidence supports this conclusion?
The foam cover was the best insulator because it kept the water at the highest temperature after 30 minutes. The foam-covered cup was 62 degrees C, while the next highest was wool at 57 degrees C and the uncovered cup was only 42 degrees C. - 8
A microbiology class tested antibiotics against one strain of bacteria. Data: control disk, 0 mm zone of inhibition; penicillin, 2 mm; tetracycline, 18 mm; ciprofloxacin, 25 mm. Which antibiotic was most effective against this bacterial strain, and what limitation should be included in the conclusion?
A larger zone of inhibition means less bacterial growth near the antibiotic disk.
Ciprofloxacin was most effective against this bacterial strain because it produced the largest zone of inhibition at 25 mm. A limitation is that the data apply only to the tested bacterial strain and conditions, so they do not prove that ciprofloxacin is most effective against all bacteria. - 9
Researchers tracked lake pH and amphibian egg hatching success. Data: pH 6.8, 92 percent hatched; pH 6.1, 73 percent hatched; pH 5.6, 45 percent hatched; pH 5.0, 18 percent hatched. Write a conclusion that connects pH to hatching success.
Remember that lower pH means more acidic conditions.
The data show that lower pH is associated with lower amphibian egg hatching success. Hatching success was 92 percent at pH 6.8, but it dropped to 18 percent at pH 5.0, showing a strong decrease as the lake became more acidic. - 10
A study recorded caffeine intake, sleep, and reaction time. Data: Group 1, 0 mg caffeine, 8 hours sleep, reaction time 260 ms; Group 2, 100 mg caffeine, 8 hours sleep, reaction time 245 ms; Group 3, 200 mg caffeine, 4 hours sleep, reaction time 310 ms; Group 4, 0 mg caffeine, 4 hours sleep, reaction time 355 ms. Explain why it would be too strong to conclude that caffeine always improves reaction time.
Look for variables that changed at the same time.
It would be too strong to conclude that caffeine always improves reaction time because sleep also changes between groups. The 8-hour sleep groups show a small improvement with 100 mg caffeine, from 260 ms to 245 ms, but the 200 mg caffeine group also had only 4 hours of sleep, so caffeine and sleep effects are mixed together. - 11
A student used a mineral identification table. Data: quartz, hardness 7, no reaction with acid; calcite, hardness 3, fizzes with acid; halite, hardness 2.5, salty taste and no acid fizz; unknown mineral, hardness 3, fizzes with acid. Which mineral is the unknown most likely to be, and what evidence supports the identification?
The unknown mineral is most likely calcite because both the unknown and calcite have hardness 3 and fizz with acid. Quartz is harder and does not react with acid, and halite is identified by salty taste and no acid fizz. - 12
A weather balloon measured air temperature at different altitudes. Data: 0 m, 22 degrees C; 1000 m, 16 degrees C; 2000 m, 10 degrees C; 3000 m, 4 degrees C; 4000 m, -2 degrees C. Calculate the average temperature change per 1000 m and predict the temperature at 2500 m.
Find the repeated difference in temperature for each 1000 m increase.
The temperature changes by an average of -6 degrees C per 1000 m because it drops from 22 degrees C to 16 degrees C from 0 m to 1000 m and follows the same pattern. At 2500 m, the predicted temperature is about 7 degrees C, halfway between 10 degrees C at 2000 m and 4 degrees C at 3000 m. - 13
Yeast was grown with different glucose concentrations. Data: 0 percent glucose, CO2 production 1 mL per hour; 1 percent, 12 mL per hour; 2 percent, 23 mL per hour; 5 percent, 26 mL per hour; 10 percent, 25 mL per hour. What conclusion can be made about glucose concentration and yeast respiration?
CO2 production is evidence of the rate of yeast respiration.
The data show that yeast respiration increases as glucose rises from 0 percent to about 5 percent, then levels off. CO2 production increased from 1 mL per hour at 0 percent glucose to 26 mL per hour at 5 percent glucose, but it did not increase further at 10 percent glucose. - 14
A biology class compared heart rate recovery after exercise. Data: trained athlete, resting heart rate 60 bpm, immediately after exercise 150 bpm, after 1 minute 110 bpm, after 3 minutes 72 bpm; non-athlete, resting heart rate 78 bpm, immediately after exercise 165 bpm, after 1 minute 145 bpm, after 3 minutes 112 bpm. Which person recovered faster, and what evidence supports your conclusion?
The trained athlete recovered faster because their heart rate returned much closer to resting level after 3 minutes. The athlete was 12 bpm above resting after 3 minutes, while the non-athlete was 34 bpm above resting after 3 minutes. - 15
Marine snails were placed in seawater with different pH levels for one month. Data: pH 8.2, average shell mass change -0.1 percent; pH 7.8, average shell mass change -2.4 percent; pH 7.4, average shell mass change -6.7 percent. Does the evidence support the claim that lower pH weakens shells? Explain using data.
A more negative mass change means the shells lost more mass.
Yes, the evidence supports the claim that lower pH weakens shells. As pH decreased from 8.2 to 7.4, shell mass loss increased from -0.1 percent to -6.7 percent, showing that more acidic water was associated with greater shell loss.