Elementary School Science Quiz: Variables And Failure Points

20 questions · exam conditions

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Variables And Failure PointsQuestion 1 of 20

Read about the test: Amir tests if fertilizer helps bean plants grow. All plants get 50 mL water daily and sit in the same window. The test variable is the fertilizer type. Which shows something that could make the test unfair?

Students measure plant height with a ruler each week

Students write down results in a science notebook

All plants are bean seeds planted in the same size pots

Some plants get watered on weekends, but others are forgotten

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Elementary School Science Quiz

Elementary School Science Quiz: Variables And Failure Points

Practice Variables And Failure Points in Elementary School Science with focused quiz questions that help you check what you know, review explanations, and build confidence with test-style prompts.

What this quiz covers

This quiz focuses on Variables And Failure Points, giving you a quick way to practice the rules, question types, and explanations that matter most for Elementary School Science.

How to use this quiz

Try each quiz question before looking at the correct answer. Use the explanations to review missed ideas, then come back to similar questions until the pattern feels familiar.

All questions

Question 1

Students measure plant height with a ruler each week
Students write down results in a science notebook
All plants are bean seeds planted in the same size pots
Some plants get watered on weekends, but others are forgotten (correct answer)

Explanation: This question tests identifying variables and failure points in testing (NGSS 3-5-ETS1-3: Plan and carry out fair tests in which variables are controlled and failure points are considered to identify aspects of a model or prototype that can be improved). Variables are factors that can change in an experiment or test. Some variables you change on purpose (test variable - what you're testing), some you keep the same (control variables - to make test fair), and some might change by accident (uncontrolled variables - things like weather). Identifying variables helps you plan fair tests and understand what affects your results. In this scenario, students are testing if fertilizer helps bean plants grow, with all plants in same pots and window getting daily water. The variables involved include fertilizer type (test variable), water amount (control variable), and inconsistent weekend watering (uncontrolled variable). Choice B is correct because some plants get watered on weekends, but others are forgotten is indeed a variable in this situation: inconsistent watering could change by accident making results unreliable. Identifying this helps students watch for it. Choice A represents confusing control variables with uncontrolled ones. Students who choose this may not understand difference between what to keep same and what could change by accident. To help students: Create three-column chart: "What We Change (Test Variable)," "What We Keep Same (Control Variables)," "What Might Change By Accident (Uncontrolled Variables)." Practice identifying: In "Does fertilizer help plants grow?" Test variable = fertilizer amount; Controls = water, sunlight, pot size, seed type; Uncontrolled = temperature, forgetting to water. Ask: "What are we testing? What must stay the same? What could change by accident?"

Question 2

Read about the test: Emma tests if bigger wings make paper airplanes fly farther. She throws 3 times for each wing size. If she throws harder sometimes, results change. Which shows something that could make the test unfair?

Measuring the distance from the start line to the nose
Using the same type of paper for every airplane
Changing wing size to see what happens (test variable)
Throwing with different force on different tries (correct answer)

Explanation: This question tests identifying variables and failure points in testing (NGSS 3-5-ETS1-3: Plan and carry out fair tests in which variables are controlled and failure points are considered to identify aspects of a model or prototype that can be improved). Variables are factors that can change in an experiment or test. Some variables you change on purpose (test variable - what you're testing), some you keep the same (control variables - to make test fair), and some might change by accident (uncontrolled variables - things like weather). Identifying variables helps you plan fair tests and understand what affects your results. In this scenario, students are testing if bigger wings make paper airplanes fly farther, throwing multiple times per size. The variables involved include wing size (test variable), throwing force (which if changed makes test unfair), and paper type (control variable). Choice C is correct because throwing with different force on different tries is indeed a variable in this situation: throwing force could change by accident making results unreliable. Identifying this helps students watch for it. Choice B represents confusing the test variable with something unfair. Students who choose this may not understand difference between what to change and what to keep same. To help students: Create three-column chart: "What We Change (Test Variable)," "What We Keep Same (Control Variables)," "What Might Change By Accident (Uncontrolled Variables)." Practice identifying: In "Does fertilizer help plants grow?" Test variable = fertilizer amount; Controls = water, sunlight, pot size, seed type; Uncontrolled = temperature, forgetting to water. Ask: "What are we testing? What must stay the same? What could change by accident?"

Question 3

Look at the design students made: Jamal built a marshmallow catapult with a spoon and rubber band. When he pulls the spoon back farther, the marshmallow goes farther, but the rubber band sometimes snaps. What is a failure point in this design?

Something might go wrong somewhere in the catapult
The marshmallow could turn into a rock during the test
The rubber band might snap when the spoon is pulled back (correct answer)
The distance the marshmallow flies is the failure point

Explanation: This question tests identifying variables and failure points in testing (NGSS 3-5-ETS1-3: Plan and carry out fair tests in which variables are controlled and failure points are considered to identify aspects of a model or prototype that can be improved). Failure points are places where a design could break, stop working, or have problems. These might be structural (parts break/snap), material-related (glue doesn't hold), design flaws (unstable, unbalanced), or testing issues (measured wrong). Identifying failure points before testing helps you strengthen weak spots or plan for problems. In this scenario, students are building and testing a marshmallow catapult with a spoon and rubber band. Potential failure points include the rubber band snapping during use. Choice A is correct because the rubber band might snap when the spoon is pulled back is a real way this design could fail: rubber band snapping would prevent catapult from launching. Recognizing this failure point helps students strengthen this part of the design. Choice B represents imagining problems that couldn't actually happen. Students who choose this may confuse realistic failures with impossible or magical events. To help students: Before testing, ask "Where could this break? What could go wrong? What parts are weak?" Create list of potential problems, then test to see which actually happen. Practice categorizing: Structural (breaks/snaps), Material (glue fails/tape unsticks), Design flaw (unbalanced/unstable), Testing error (measured wrong/variables changed). Use sentence frame: "[Part] might [type of failure] because [reason]."

Question 4

Look at the design students made: Keisha built a solar oven from a pizza box and foil. On cloudy days, the marshmallow does not melt, and opening the box lets heat out. Which is an uncontrolled variable (might change by accident)?

How sunny or cloudy the day is during the test (correct answer)
The foil is a variable because it is shiny
The melted marshmallow is the variable they change on purpose
The marshmallow is heated because that is the goal

Explanation: This question tests identifying variables and failure points in testing (NGSS 3-5-ETS1-3: Plan and carry out fair tests in which variables are controlled and failure points are considered to identify aspects of a model or prototype that can be improved). Variables are factors that can change in an experiment or test. Some variables you change on purpose (test variable - what you're testing), some you keep the same (control variables - to make test fair), and some might change by accident (uncontrolled variables - things like weather). Identifying variables helps you plan fair tests and understand what affects your results. In this scenario, students are building and testing a solar oven from a pizza box and foil to melt marshmallows. The variables involved include weather conditions like sunniness (uncontrolled variable) and opening the box (which affects heat). Choice A is correct because how sunny or cloudy the day is during the test is indeed a variable in this situation: weather could change by accident making results unreliable. Identifying this helps students watch for it. Choice B represents confusing the result with a variable. Students who choose this may think the result is a variable when it's what you measure. To help students: Create three-column chart: "What We Change (Test Variable)," "What We Keep Same (Control Variables)," "What Might Change By Accident (Uncontrolled Variables)." Practice identifying: In "Does fertilizer help plants grow?" Test variable = fertilizer amount; Controls = water, sunlight, pot size, seed type; Uncontrolled = temperature, forgetting to water. Ask: "What are we testing? What must stay the same? What could change by accident?"

Question 5

Read about the test: Chen builds bridges from popsicle sticks and glue. He tests how many sticks make the bridge stronger by adding pennies. Some joints come apart if glue is weak. Where could this design break or stop working?

The bridge could fail where joints are poorly glued and come apart (correct answer)
The bridge has sticks, and that is the failure point
The bridge could grow taller like a plant during the test
The number of pennies is the place where it breaks

Explanation: This question tests identifying variables and failure points in testing (NGSS 3-5-ETS1-3: Plan and carry out fair tests in which variables are controlled and failure points are considered to identify aspects of a model or prototype that can be improved). Failure points are places where a design could break, stop working, or have problems. These might be structural (parts break/snap), material-related (glue doesn't hold), design flaws (unstable, unbalanced), or testing issues (measured wrong). Identifying failure points before testing helps you strengthen weak spots or plan for problems. In this scenario, students are building and testing popsicle stick bridges by changing the number of sticks and adding pennies. Potential failure points include weak glue joints coming apart. Choice A is correct because the bridge could fail where joints are poorly glued and come apart is a real way this design could fail: weak glue means joints are unstable and bridge could collapse. Recognizing this failure point helps students strengthen this part of the design. Choice B represents imagining problems that couldn't actually happen. Students who choose this may confuse normal features with failures or pick impossible events. To help students: Before testing, ask "Where could this break? What could go wrong? What parts are weak?" Create list of potential problems, then test to see which actually happen. Practice categorizing: Structural (breaks/snaps), Material (glue fails/tape unsticks), Design flaw (unbalanced/unstable), Testing error (measured wrong/variables changed). Use sentence frame: "[Part] might [type of failure] because [reason]."

Question 6

Read about the test: Marcus tests bridges to see if triangle supports hold more pennies. He uses the same length bridge each time, but sometimes the glue is still wet. What might go wrong during this test?

The bridge might start talking when pennies are added
The bridge is a variable because it is on the table
The bridge pattern is the result they measure with a ruler
Wet glue might make joints weak, so the bridge breaks early (correct answer)

Explanation: This question tests identifying variables and failure points in testing (NGSS 3-5-ETS1-3: Plan and carry out fair tests in which variables are controlled and failure points are considered to identify aspects of a model or prototype that can be improved). Failure points are places where a design could break, stop working, or have problems. These might be structural (parts break/snap), material-related (glue doesn't hold), design flaws (unstable, unbalanced), or testing issues (measured wrong). Identifying failure points before testing helps you strengthen weak spots or plan for problems. In this scenario, students are building and testing bridges with triangle supports to hold pennies, using same length each time. Potential failure points include wet glue making joints weak. Choice A is correct because wet glue might make joints weak, so the bridge breaks early is a real way this design could fail: wet glue means joints are unstable and could collapse under weight. Recognizing this failure point helps students strengthen this part of the design. Choice B represents imagining problems that couldn't actually happen. Students who choose this may confuse normal features with failures or pick magical events. To help students: Before testing, ask "Where could this break? What could go wrong? What parts are weak?" Create list of potential problems, then test to see which actually happen. Practice categorizing: Structural (breaks/snaps), Material (glue fails/tape unsticks), Design flaw (unbalanced/unstable), Testing error (measured wrong/variables changed). Use sentence frame: "[Part] might [type of failure] because [reason]."

Question 7

Read about the test. Chen built a catapult to launch marshmallows. He wants to test if spoon size matters, so he uses the same marshmallow weight and pulls back 4 inches each time. Sometimes the rubber band snaps when pulled. Where could this design break or stop working?

The marshmallow could turn into popcorn during the launch.
The rubber band could snap when the spoon is pulled back. (correct answer)
The test is about spoon size, so spoon size must stay same.
The distance the marshmallow flies is the only control variable.

Explanation: This question tests identifying variables and failure points in testing (NGSS 3-5-ETS1-3: Plan and carry out fair tests in which variables are controlled and failure points are considered to identify aspects of a model or prototype that can be improved). Failure points are places where a design could break, stop working, or have problems. These might be structural (parts break/snap), material-related (glue doesn't hold), design flaws (unstable, unbalanced), or testing issues (measured wrong). In this scenario, Chen is testing if spoon size matters in a catapult design for launching marshmallows, controlling marshmallow weight and pull-back distance. Potential failure points include the rubber band that provides the launching force. Choice B is correct because the rubber band snapping when pulled back is a real way this design could fail: rubber bands can wear out or be pulled beyond their elastic limit, and if it snaps, the catapult cannot launch anything, stopping the entire test. Choice A represents imagining problems that couldn't actually happen - students who choose this may have creative imaginations but don't recognize that marshmallows cannot transform into popcorn during a catapult launch. To help students: Before testing, ask "Where could this break? What could go wrong? What parts are weak?" Practice categorizing: Structural (breaks/snaps), Material (glue fails/tape unsticks), Design flaw (unbalanced/unstable), Testing error (measured wrong/variables changed).

Question 8

Read about the test. Marcus and Emma test a popsicle-stick bridge with books. They want to test if triangle supports are stronger than square supports. They keep the bridge width the same, but one bridge is much longer. Which shows something that could make the test unfair?

Using different bridge lengths could change how much it bends. (correct answer)
The bridge is made of wood, so it is brown.
How many books it holds is the test variable to change.
Triangle supports are shapes, so shapes are unfair.

Explanation: This question tests identifying variables and failure points in testing (NGSS 3-5-ETS1-3: Plan and carry out fair tests in which variables are controlled and failure points are considered to identify aspects of a model or prototype that can be improved). Variables are factors that can change in an experiment or test. Some variables you change on purpose (test variable - what you're testing), some you keep the same (control variables - to make test fair), and some might change by accident (uncontrolled variables - things like weather). In this scenario, Marcus and Emma are testing whether triangle supports are stronger than square supports in popsicle-stick bridges. The variables involved include support shape (test variable), bridge width (control), and bridge length (which should be controlled but isn't). Choice A is correct because using different bridge lengths is indeed an uncontrolled variable in this situation: longer bridges naturally bend more under weight than shorter ones, so if one bridge is much longer, differences in book-holding capacity could be from length rather than support shape, making the test unfair. Choice C represents confusing the result with a test variable - students who choose this may think the number of books held should be changed on purpose, when it's actually what they measure to determine which support shape is stronger. To help students: Create three-column chart: "What We Change (Test Variable)," "What We Keep Same (Control Variables)," "What Might Change By Accident (Uncontrolled Variables)." Emphasize that all factors except the one being tested should stay the same.

Question 9

Read about the test: Carlos tests catapults to see if spoon size matters. He must keep marshmallow weight, pull-back distance, and rubber band the same each time. What variables should students keep the same in this test?

Keep the classroom lights the same color each try
Keep marshmallow weight and pull-back distance the same each try (correct answer)
Keep how far it flies the same each try (that is the result)
Keep spoon size the same, and change rubber band each try

Explanation: This question tests identifying variables and failure points in testing (NGSS 3-5-ETS1-3: Plan and carry out fair tests in which variables are controlled and failure points are considered to identify aspects of a model or prototype that can be improved). Variables are factors that can change in an experiment or test. Some variables you change on purpose (test variable - what you're testing), some you keep the same (control variables - to make test fair), and some might change by accident (uncontrolled variables - things like weather). Identifying variables helps you plan fair tests and understand what affects your results. In this scenario, students are testing if spoon size affects catapult performance. The variables involved include spoon size (test variable), marshmallow weight, pull-back distance, and rubber band (control variables). Choice B is correct because marshmallow weight and pull-back distance must be kept the same so differences come only from spoon size being tested. Identifying this helps students control it. Choice C represents confusing the result with a control variable. Students who choose this may think the result is a variable when it's what you measure. To help students: Create three-column chart: "What We Change (Test Variable)," "What We Keep Same (Control Variables)," "What Might Change By Accident (Uncontrolled Variables)." Practice identifying: In "Does fertilizer help plants grow?" Test variable = fertilizer amount; Controls = water, sunlight, pot size, seed type; Uncontrolled = temperature, forgetting to water. Ask: "What are we testing? What must stay the same? What could change by accident?"

Question 10

Look at the design students made. Jamal and Sofia built a popsicle-stick bridge and test it with pennies. They change the number of sticks in the middle, but keep the bridge length the same. Some glue is still wet, and a joint pulls apart. What is a failure point in this design?

The bridge is made of sticks, so it is a bridge.
A wet glue joint could come apart when pennies are added. (correct answer)
The number of pennies on the bridge is the test result.
The bridge length should change every time to be fair.

Explanation: This question tests identifying variables and failure points in testing (NGSS 3-5-ETS1-3: Plan and carry out fair tests in which variables are controlled and failure points are considered to identify aspects of a model or prototype that can be improved). Failure points are places where a design could break, stop working, or have problems. These might be structural (parts break/snap), material-related (glue doesn't hold), design flaws (unstable, unbalanced), or testing issues (measured wrong). In this scenario, students are testing a popsicle-stick bridge by changing the number of sticks in the middle while keeping bridge length constant. Potential failure points include wet glue joints that haven't fully dried. Choice B is correct because a wet glue joint coming apart is a real way this design could fail: if the glue hasn't dried completely, the joints are weak and could separate when weight is added, causing the bridge to collapse. Choice C represents confusing the test result with a failure point - students who choose this may not understand that the number of pennies the bridge holds is what they're measuring, not a way the design could fail. To help students: Before testing, ask "Where could this break? What could go wrong? What parts are weak?" Create list of potential problems, then test to see which actually happen.

Question 11

Read about the test: Maya tests wing size on paper airplanes. She uses the same paper, throws from the same spot indoors, and measures how far the nose lands each time. Which variable should students control to make the test fair?

Change the wing size each time (that is what they test)
Measure the distance it flies (that is the result)
Keep the throwing force the same each time (control variable) (correct answer)
Use a stopwatch to time the flight (not part of this test)

Explanation: This question tests identifying variables and failure points in testing (NGSS 3-5-ETS1-3: Plan and carry out fair tests in which variables are controlled and failure points are considered to identify aspects of a model or prototype that can be improved). Variables are factors that can change in an experiment or test. Some variables you change on purpose (test variable - what you're testing), some you keep the same (control variables - to make test fair), and some might change by accident (uncontrolled variables - things like weather). Identifying variables helps you plan fair tests and understand what affects your results. In this scenario, students are testing how wing size affects paper airplane flight distance, using the same paper and throwing spot. The variables involved include wing size (test variable), throwing force (control variable), and flight distance (result). Choice B is correct because throwing force must be kept the same so differences come only from wing size being tested. Identifying this helps students control it. Choice A represents confusing the test variable with a control variable. Students who choose this may think the thing being tested should be kept the same instead of changed on purpose. To help students: Create three-column chart: "What We Change (Test Variable)," "What We Keep Same (Control Variables)," "What Might Change By Accident (Uncontrolled Variables)." Practice identifying: In "Does fertilizer help plants grow?" Test variable = fertilizer amount; Controls = water, sunlight, pot size, seed type; Uncontrolled = temperature, forgetting to water. Ask: "What are we testing? What must stay the same? What could change by accident?"

Question 12

Read about the solar oven test. What is one failure point in this design?

The box might not be sealed, so heat escapes (correct answer)
Students can change how long they leave it in the sun
The foil is shiny, so it reflects sunlight
The marshmallow gets warm after sitting in the sun

Explanation: This question tests identifying variables and failure points in testing (NGSS 3-5-ETS1-3: Plan and carry out fair tests in which variables are controlled and failure points are considered to identify aspects of a model or prototype that can be improved). Failure points are places where a design could break, stop working, or have problems. These might be structural (parts break/snap), material-related (glue doesn't hold), design flaws (unstable, unbalanced), or testing issues (measured wrong). Identifying failure points before testing helps you strengthen weak spots or plan for problems. In this scenario, students are building a solar oven to heat a marshmallow using sunlight. Potential failure points include poor sealing or heat loss. Choice B is correct because the box not being sealed is a real way this design could fail: heat escaping would prevent the oven from warming up effectively. Recognizing this failure point helps students strengthen this part of the design. Choice A represents confusing normal features with failures. Students who choose this may not recognize specific weak points in the design and pick intended properties as problems. To help students: Before testing, ask "Where could this break? What could go wrong? What parts are weak?" Create list of potential problems, then test to see which actually happen. Practice categorizing: Structural (breaks/snaps), Material (glue fails/tape unsticks), Design flaw (unbalanced/unstable), Testing error (measured wrong/variables changed). Use sentence frame: "[Part] might [type of failure] because [reason]."

Question 13

Read about the test. Maya tests wing size on paper airplanes. She uses the same paper, throws from 5 feet high, and tries the same throw each time. One day a fan is on, and the planes drift sideways. Which shows something that could make the test unfair?

The fan blowing air makes the planes drift during some throws. (correct answer)
The airplanes are made of paper, so they can fold.
The distance the plane flies is the variable she should change.
The classroom has a ceiling, so the planes stay inside.

Explanation: This question tests identifying variables and failure points in testing (NGSS 3-5-ETS1-3: Plan and carry out fair tests in which variables are controlled and failure points are considered to identify aspects of a model or prototype that can be improved). Variables are factors that can change in an experiment or test. Some variables you change on purpose (test variable - what you're testing), some you keep the same (control variables - to make test fair), and some might change by accident (uncontrolled variables - things like weather). In this scenario, Maya is testing wing size on paper airplanes while trying to control other factors like paper type, throwing height, and throwing force. Choice A is correct because the fan blowing air is indeed an uncontrolled variable in this situation: it changes the flight conditions between throws, making some planes drift sideways while others might not be affected, which makes the test unfair since differences in flight distance could be from the fan rather than wing size. Choice B represents confusing a material property with a variable - students who choose this may think that because paper can fold, this is somehow a variable, when folding ability is just a characteristic of the material, not something that changes during the test. To help students: Create three-column chart: "What We Change (Test Variable)," "What We Keep Same (Control Variables)," "What Might Change By Accident (Uncontrolled Variables)." Practice identifying: In "Does fertilizer help plants grow?" Test variable = fertilizer amount; Controls = water, sunlight, pot size, seed type; Uncontrolled = temperature, forgetting to water.

Question 14

Read about the experiment. Amir grows bean plants to test fertilizer. He uses the same bean seeds, same size pots, and 1 cup of water each day. The one thing he changes is the fertilizer type. Which is a variable students can change in this experiment?

The type of fertilizer used on the plants (what he changes). (correct answer)
The plants are green, so green is the variable.
How tall the plants grow is the only thing to keep same.
The classroom door should be open to help plants grow.

Explanation: This question tests identifying variables and failure points in testing (NGSS 3-5-ETS1-3: Plan and carry out fair tests in which variables are controlled and failure points are considered to identify aspects of a model or prototype that can be improved). Variables are factors that can change in an experiment or test. Some variables you change on purpose (test variable - what you're testing), some you keep the same (control variables - to make test fair), and some might change by accident (uncontrolled variables - things like weather). In this scenario, Amir is growing bean plants to test fertilizer effectiveness. The variables involved include fertilizer type (test variable), bean seeds, pot size, and water amount (control variables). Choice A is correct because the type of fertilizer is indeed the test variable in this situation: it's what Amir purposely changes to see its effect on plant growth, while keeping everything else constant to ensure any differences in growth come from the fertilizer type alone. Choice C represents not understanding the difference between what to change and what to keep same - students who choose this may confuse the result (plant height) with a control variable, when height is actually what they measure, not something they control. To help students: Create three-column chart: "What We Change (Test Variable)," "What We Keep Same (Control Variables)," "What Might Change By Accident (Uncontrolled Variables)." Ask: "What are we testing? What must stay the same? What could change by accident?"

Question 15

Read about the test. Sofia uses a catapult to launch marshmallows. She notices heavier marshmallows do not fly as far. She also sees the base sometimes tips over when she launches. What is a failure point in this design?

The base could tip over when the catapult launches a marshmallow. (correct answer)
Heavier marshmallows fly less distance, so distance is the failure.
The catapult is a variable because it is on the table.
The marshmallow could explode like fireworks during the launch.

Explanation: This question tests identifying variables and failure points in testing (NGSS 3-5-ETS1-3: Plan and carry out fair tests in which variables are controlled and failure points are considered to identify aspects of a model or prototype that can be improved). Failure points are places where a design could break, stop working, or have problems. These might be structural (parts break/snap), material-related (glue doesn't hold), design flaws (unstable, unbalanced), or testing issues (measured wrong). In this scenario, Sofia is using a catapult to launch marshmallows and has noticed that heavier marshmallows don't fly as far. Potential failure points include the base tipping over during launches. Choice A is correct because the base tipping over when launching is a real way this design could fail: if the base isn't stable or heavy enough, the force of the launch can cause the whole catapult to tip, ruining the launch and making consistent testing impossible. Choice D represents imagining problems that couldn't actually happen - students who choose this may have creative imaginations but don't recognize that marshmallows cannot explode like fireworks from being launched. To help students: Before testing, ask "Where could this break? What could go wrong? What parts are weak?" Use sentence frame: "[Part] might [type of failure] because [reason]."

Question 16

Read about the test. Carlos makes a water bottle rocket and wants to test fin design. He keeps the same bottle and uses 2 cups of water each launch. Sometimes the cap leaks air before he launches. What might go wrong during this test?

The rocket might leak air at the cap and not launch well. (correct answer)
The rocket might melt because it is flying in the sky.
The fin design is the control variable and must stay same.
The rocket is a variable because it is a rocket.

Explanation: This question tests identifying variables and failure points in testing (NGSS 3-5-ETS1-3: Plan and carry out fair tests in which variables are controlled and failure points are considered to identify aspects of a model or prototype that can be improved). Failure points are places where a design could break, stop working, or have problems. These might be structural (parts break/snap), material-related (glue doesn't hold), design flaws (unstable, unbalanced), or testing issues (measured wrong). In this scenario, Carlos is testing fin design on a water bottle rocket while keeping the bottle type and water amount constant. Potential failure points include the cap seal where air pressure builds up. Choice A is correct because the rocket leaking air at the cap is a real way this design could fail: if the cap doesn't seal properly, the pressurized air escapes before launch, reducing the launching force and making the rocket perform poorly regardless of fin design. Choice B represents imagining problems that couldn't actually happen - students who choose this may think rockets get hot from flying, but water bottle rockets don't generate heat that could melt plastic. To help students: Before testing, ask "Where could this break? What could go wrong? What parts are weak?" Use sentence frame: "[Part] might [type of failure] because [reason]."

Question 17

Look at the design students made. Yuki builds a solar oven from a pizza box and foil to melt a marshmallow. She keeps the marshmallow in for 10 minutes each time. The box lid does not close tight, so warm air escapes. What is one way this design could fail?

Heat could escape because the box is not sealed tightly. (correct answer)
The sun could turn off because someone flipped a switch.
The 10 minutes is the test variable that should change.
The foil is shiny, so shiny foil is a failure point.

Explanation: This question tests identifying variables and failure points in testing (NGSS 3-5-ETS1-3: Plan and carry out fair tests in which variables are controlled and failure points are considered to identify aspects of a model or prototype that can be improved). Failure points are places where a design could break, stop working, or have problems. These might be structural (parts break/snap), material-related (glue doesn't hold), design flaws (unstable, unbalanced), or testing issues (measured wrong). In this scenario, Yuki built a solar oven from a pizza box and foil to melt marshmallows, keeping time constant at 10 minutes. Potential failure points include the loose-fitting lid that allows heat to escape. Choice A is correct because heat escaping through an unsealed box is a real way this design could fail: solar ovens work by trapping heat inside, and if the lid doesn't close tightly, warm air escapes and the temperature won't get high enough to melt the marshmallow. Choice B represents imagining problems that couldn't actually happen - students who choose this may not understand that the sun is not controlled by switches like electric lights. To help students: Before testing, ask "Where could this break? What could go wrong? What parts are weak?" Practice categorizing failure types and focus on realistic problems based on how the design actually works.

Question 18

Read about the test. Jamal makes a water bottle rocket and tests how much water to use. He tries 1 cup, 2 cups, and 3 cups of water, but pumps the same number of times. Sometimes the fins are crooked, and the rocket spins and crashes. Where could this design break or stop working?

Crooked fins could make the rocket spin and crash after launch. (correct answer)
The rocket could grow leaves because it has water inside.
Amount of water is the control variable and must stay same.
How high it flies is the variable he should change on purpose.

Explanation: This question tests identifying variables and failure points in testing (NGSS 3-5-ETS1-3: Plan and carry out fair tests in which variables are controlled and failure points are considered to identify aspects of a model or prototype that can be improved). Failure points are places where a design could break, stop working, or have problems. These might be structural (parts break/snap), material-related (glue doesn't hold), design flaws (unstable, unbalanced), or testing issues (measured wrong). In this scenario, Jamal is testing how much water to use in a water bottle rocket, trying different amounts while keeping pump strokes constant. Potential failure points include crooked fins that affect flight stability. Choice A is correct because crooked fins making the rocket spin and crash is a real way this design could fail: fins provide stability during flight, and if they're not straight or properly attached, they create uneven air resistance causing the rocket to spin out of control and crash regardless of water amount. Choice B represents imagining problems that couldn't actually happen - students who choose this may not understand that water in a rocket is just propellant, not something that could cause plant growth. To help students: Before testing, ask "Where could this break? What could go wrong? What parts are weak?" Practice categorizing: Structural (breaks/snaps), Material (glue fails/tape unsticks), Design flaw (unbalanced/unstable), Testing error (measured wrong/variables changed).

Question 19

Read about the test. Carlos tests a catapult and changes spoon size. He keeps the marshmallow weight the same and pulls back 10 cm each time. What variables should students keep the same in this test?

Keep spoon size the same for every launch
Keep marshmallow weight and pull-back distance the same (correct answer)
Keep how far it flies the same each time
Keep the classroom the same color each day

Explanation: This question tests identifying variables and failure points in testing (NGSS 3-5-ETS1-3: Plan and carry out fair tests in which variables are controlled and failure points are considered to identify aspects of a model or prototype that can be improved). Variables are factors that can change in an experiment or test. Some variables you change on purpose (test variable - what you're testing), some you keep the same (control variables - to make test fair), and some might change by accident (uncontrolled variables - things like weather). In this scenario, students are testing how spoon size affects catapult performance. The variables involved include spoon size (test variable), marshmallow weight (control variable), and pull-back distance (control variable). Choice B is correct because marshmallow weight and pull-back distance are indeed variables in this situation: they must be kept the same so differences in launch distance come only from spoon size being tested. Identifying this helps students control these factors for a fair test. Choice C represents not understanding the difference between variables and results. Students who choose this may think they need to control the outcome (flight distance) when that's actually what varies based on the test variable. To help students: Create three-column chart: "What We Change (Test Variable)," "What We Keep Same (Control Variables)," "What Might Change By Accident (Uncontrolled Variables)." Practice identifying: In "Does fertilizer help plants grow?" Test variable = fertilizer amount; Controls = water, sunlight, pot size, seed type; Uncontrolled = temperature, forgetting to water. Ask: "What are we testing? What must stay the same? What could change by accident?"

Question 20

Read about the test. Keisha tests if bridge length changes strength. She builds bridges 15 cm and 30 cm long, but uses the same number of sticks and same glue. Which is a variable students can change in this experiment?

Bridge length (the one thing they change on purpose) (correct answer)
Amount of glue used (keep the same for fairness)
How much weight it holds (this is what they measure)
The table under the bridge (not part of the test factor)

Explanation: This question tests identifying variables and failure points in testing (NGSS 3-5-ETS1-3: Plan and carry out fair tests in which variables are controlled and failure points are considered to identify aspects of a model or prototype that can be improved). Variables are factors that can change in an experiment or test. Some variables you change on purpose (test variable - what you're testing), some you keep the same (control variables - to make test fair), and some might change by accident (uncontrolled variables - things like weather). In this scenario, students are testing if bridge length affects strength. The variables involved include bridge length (test variable), number of sticks (control variable), and amount of glue (control variable). Choice A is correct because bridge length is indeed a variable in this situation: it's what students change on purpose (15 cm vs 30 cm) to test its effect on bridge strength. Identifying this helps students test it systematically. Choice C represents confusing the result with a variable. Students who choose this may think the outcome (weight held) is a variable when it's actually what you measure as a result of changing the test variable. To help students: Create three-column chart: "What We Change (Test Variable)," "What We Keep Same (Control Variables)," "What Might Change By Accident (Uncontrolled Variables)." Practice identifying: In "Does fertilizer help plants grow?" Test variable = fertilizer amount; Controls = water, sunlight, pot size, seed type; Uncontrolled = temperature, forgetting to water. Ask: "What are we testing? What must stay the same? What could change by accident?"