Practice writing claims, evidence, and reasoning based on data from simple middle school science investigations.
Read each lab scenario and data set carefully. Write a clear CER response using a claim, specific evidence from the data, and reasoning that connects the evidence to the science idea.
Using evidence and reasoning to explain lab results
Science - Grade 6-8
- 1
A student tested how the amount of sunlight affects bean plant growth. Four plants were grown for 14 days with different amounts of sunlight each day. Sunlight per day: 2 hours, 4 hours, 6 hours, 8 hours Average plant height after 14 days: 5 cm, 9 cm, 13 cm, 16 cm Write a CER response explaining how sunlight affected plant growth.
- 2
A class investigated whether water temperature affects how fast sugar dissolves. They added the same amount of sugar to 100 mL of water at different temperatures and stirred at the same speed. Water temperature: 10°C, 25°C, 40°C, 60°C Time to dissolve sugar: 95 s, 62 s, 38 s, 21 s Write a CER response explaining the relationship between temperature and dissolving time.
- 3
Students measured the bounce height of a rubber ball dropped from different heights. The same ball was used each time. Drop height: 50 cm, 100 cm, 150 cm, 200 cm Bounce height: 32 cm, 65 cm, 97 cm, 129 cm Write a CER response explaining how drop height affected bounce height.
- 4
A student tested which material is the best insulator for keeping water warm. Four identical cups were wrapped in different materials. Each cup started with water at 80°C. The temperature was recorded after 20 minutes. Material: no wrap, paper towel, cotton cloth, aluminum foil Temperature after 20 minutes: 48°C, 55°C, 61°C, 53°C Write a CER response identifying the best insulator in this test.
- 5
A group tested how fertilizer affects radish plant growth. They used the same type of soil, light, water, and seeds for all groups. Fertilizer amount: 0 g, 2 g, 4 g, 8 g Average plant height after 21 days: 7 cm, 11 cm, 15 cm, 12 cm Write a CER response explaining what the data show about fertilizer amount and plant growth.
- 6
Students tested four mystery liquids with red and blue litmus paper. Red litmus turns blue in a base. Blue litmus turns red in an acid. Liquid A: red litmus stayed red, blue litmus turned red Liquid B: red litmus turned blue, blue litmus stayed blue Liquid C: red litmus stayed red, blue litmus stayed blue Liquid D: red litmus turned blue, blue litmus stayed blue Write a CER response identifying which liquids are acids, bases, or neutral.
- 7
A student investigated how surface type affects the distance a toy car travels after rolling down the same ramp. Surface: smooth tile, cardboard, carpet, sandpaper Distance traveled: 240 cm, 180 cm, 95 cm, 60 cm Write a CER response explaining how surface type affected the toy car's motion.
- 8
Students measured how much a spring stretched when different masses were attached. Mass attached: 50 g, 100 g, 150 g, 200 g Spring stretch: 2 cm, 4 cm, 6 cm, 8 cm Write a CER response explaining the pattern between mass and spring stretch.
- 9
A class tested how the shape of a paper airplane affects flight distance. Each design was thrown by the same person with the same throwing motion. Design: wide wings, narrow wings, short body, long body Average flight distance: 6.2 m, 8.5 m, 5.7 m, 7.9 m Write a CER response identifying which design flew farthest and why the evidence supports that claim.
- 10
Students placed identical ice cubes on different colored paper in sunlight and measured how long each ice cube took to melt. Paper color: white, yellow, blue, black Melting time: 18 min, 16 min, 12 min, 8 min Write a CER response explaining how paper color affected melting time.
- 11
A student tested the effect of salt on the freezing point of water. Four cups had the same amount of water but different amounts of salt mixed in. The freezing temperature was recorded. Salt added: 0 tsp, 1 tsp, 2 tsp, 3 tsp Freezing temperature: 0°C, -2°C, -5°C, -7°C Write a CER response explaining how salt affected the freezing point of water.
- 12
Students investigated how exercise affects heart rate. One student measured their pulse before exercise and after jogging for different lengths of time. Condition: resting, 1 min jogging, 3 min jogging, 5 min jogging Heart rate: 72 bpm, 96 bpm, 124 bpm, 148 bpm Write a CER response explaining how exercise time affected heart rate.
- 13
A group studied how soil type affects how much water drains through it in 5 minutes. Each cup had the same amount of soil and received 100 mL of water. Soil type: sand, garden soil, clay, gravel Water drained: 86 mL, 54 mL, 18 mL, 92 mL Write a CER response explaining which soil allowed the most drainage and which held the most water.
- 14
Students tested how the number of wire coils affects the strength of an electromagnet. They wrapped insulated wire around an iron nail and counted how many paper clips it picked up. Number of coils: 10, 20, 30, 40 Paper clips picked up: 4, 9, 15, 21 Write a CER response explaining how the number of coils affected electromagnet strength.
- 15
A class collected data on how beak shape affects the ability to pick up different foods. Each tool represented a bird beak. Students counted how many beans each tool could pick up in 30 seconds. Beak tool: spoon, tweezers, clothespin, chopsticks Beans picked up: 28, 18, 12, 9 Write a CER response explaining which beak shape was best for picking up beans and how this relates to adaptation.