Plant Matter from Air and Water - 5th Grade Science

Plants in a chamber with no CO did not grow, but plants with extra CO grew larger. What does this evidence show about plant matter sources?
Answer: mostly from air (CO) and water, not soil This question tests the ability to use evidence to explain that plant matter comes mostly from air and water (NGSS 5-LS1-1). Students must interpret experimental evidence to support the claim that plants get materials chiefly from air and water, not soil. Multiple types of evidence prove that most plant matter comes from air and water, not soil: Van Helmont's famous willow tree experiment showed that a tree gained 164 pounds while the soil lost only 0.1 pound—the tree's mass couldn't have come from soil because the soil barely decreased; chemical analysis shows plants are 45% carbon (from CO₂ in air), 42% oxygen (from H₂O and CO₂), and 6% hydrogen (from H₂O)—totaling about 93% from air and water, with only about 6-7% from soil minerals; hydroponic experiments prove plants can grow without soil at all, showing soil is not the source of plant matter; when scientists remove carbon dioxide from air, plants stop growing; when they add more CO₂, plants grow faster—this proves carbon from air is essential for building plant mass; all this evidence leads to one conclusion: plants get their matter chiefly from carbon dioxide in air and water, with small amounts of minerals from soil. Choice B is correct because it accurately states that plant matter comes mostly from air (CO₂) and water, not soil, which matches what the evidence demonstrates—removing CO₂ stopped growth and adding it increased growth, showing CO₂ from air is essential for mass. Choice A fails because it claims soil is the main source and downplays CO₂ when the evidence shows CO₂ is crucial, representing the common misconception that plants get their matter from soil because we see plants growing in soil—but the evidence proves otherwise. To help students understand evidence for air and water as matter sources: Present Van Helmont's experiment as a mystery: 'The tree gained 164 pounds. The soil lost only 0.1 pound. Where did 164 pounds come from?' Students often guess soil until they see the numbers; emphasize: If the tree got 164 pounds from soil, the soil would weigh 164 pounds less—it doesn't—so the matter came from somewhere else; present the chemical composition evidence: 'Plants are made of carbon, hydrogen, and oxygen—where do these atoms come from? Carbon from CO₂ in air, hydrogen and oxygen from H₂O—that's 93% of the plant right there!'; use hydroponics as modern evidence: 'If plants got their matter from soil, they couldn't grow without soil—but they can—proving matter doesn't come mainly from soil'; teach the phrase: 'Plants don't eat soil—plants are made of air and water'; do the math together: 'If plants were made mostly of soil, the soil would disappear as the plant grows—does that happen? No—so plants must be made of something else—air and water'; watch for students who trust their intuition ('it must be soil') over evidence, or who don't understand that invisible gases (CO₂) have mass and can become solid plant matter; always return to evidence: 'What do the numbers show? What do experiments prove?'
In Van Helmont's test, soil weight stayed almost the same while the tree got much heavier. What does this experiment show?
Answer: mostly from air and water, not mostly from soil This question tests the ability to use evidence to explain that plant matter comes mostly from air and water (NGSS 5-LS1-1). Students must interpret Van Helmont's experimental evidence to support the claim that plants get materials chiefly from air and water, not soil. Van Helmont's experiment provides clear quantitative evidence: while the tree became much heavier (gaining mass), the soil weight stayed almost the same (losing minimal mass). If the tree's new mass came from soil, the soil would have lost an amount equal to what the tree gained—but it didn't, proving the mass came from elsewhere: air and water. Choice A is correct because it accurately states that plant matter comes mostly from air and water, not mostly from soil, which Van Helmont's evidence clearly demonstrates through the dramatic difference between tree mass gain and soil mass loss. Choice C fails because it claims 'air has no mass,' but the evidence proves otherwise—the tree's mass had to come from somewhere, and since it wasn't soil, it must be from air (CO₂ has mass) and water. To help students grasp this evidence: Use a balance scale analogy—'If you move 100 marbles from one side to the other, what happens to each side's weight?' Apply this to Van Helmont: 'If the tree took its mass from soil, the soil would lose what the tree gained. Did that happen? No—so the mass came from air and water instead.'
Plant composition data show 45% carbon from CO, 42% oxygen, and 6% hydrogen from water. What does this evidence show about plant matter sources?
Answer: mostly from air (CO) and water, with little from soil This question tests the ability to use evidence to explain that plant matter comes mostly from air and water (NGSS 5-LS1-1). Students must interpret experimental evidence to support the claim that plants get materials chiefly from air and water, not soil. Multiple types of evidence prove that most plant matter comes from air and water, not soil: Van Helmont's famous willow tree experiment showed that a tree gained 164 pounds while the soil lost only 0.1 pound—the tree's mass couldn't have come from soil because the soil barely decreased; chemical analysis shows plants are 45% carbon (from CO₂ in air), 42% oxygen (from H₂O and CO₂), and 6% hydrogen (from H₂O)—totaling about 93% from air and water, with only about 6-7% from soil minerals; hydroponic experiments prove plants can grow without soil at all, showing soil is not the source of plant matter; when scientists remove carbon dioxide from air, plants stop growing; when they add more CO₂, plants grow faster—this proves carbon from air is essential for building plant mass; all this evidence leads to one conclusion: plants get their matter chiefly from carbon dioxide in air and water, with small amounts of minerals from soil. Choice A is correct because it accurately states that plant matter comes mostly from air (CO₂) and water, with little from soil, which matches what the evidence demonstrates—plants are 45% carbon from CO₂, 42% oxygen, and 6% hydrogen from water, totaling about 93% from air and water. Choice B fails because it claims soil is the main source when the evidence shows only about 6-7% from soil minerals, representing the common misconception that plants get their matter from soil because we see plants growing in soil—but the evidence proves otherwise. To help students understand evidence for air and water as matter sources: Present Van Helmont's experiment as a mystery: 'The tree gained 164 pounds. The soil lost only 0.1 pound. Where did 164 pounds come from?' Students often guess soil until they see the numbers; emphasize: If the tree got 164 pounds from soil, the soil would weigh 164 pounds less—it doesn't—so the matter came from somewhere else; present the chemical composition evidence: 'Plants are made of carbon, hydrogen, and oxygen—where do these atoms come from? Carbon from CO₂ in air, hydrogen and oxygen from H₂O—that's 93% of the plant right there!'; use hydroponics as modern evidence: 'If plants got their matter from soil, they couldn't grow without soil—but they can—proving matter doesn't come mainly from soil'; teach the phrase: 'Plants don't eat soil—plants are made of air and water'; do the math together: 'If plants were made mostly of soil, the soil would disappear as the plant grows—does that happen? No—so plants must be made of something else—air and water'; watch for students who trust their intuition ('it must be soil') over evidence, or who don't understand that invisible gases (CO₂) have mass and can become solid plant matter; always return to evidence: 'What do the numbers show? What do experiments prove?'
A 100-gram plant (dry mass) is about 45 g carbon from CO₂ in air, 42 g oxygen from water and CO₂, and 6 g hydrogen from water—93 g total from air and water. Only about 7 g comes from soil minerals. What does this data demonstrate about plant matter?
Answer: mostly from air and water, with a small part from soil minerals This question tests the ability to use evidence to explain that plant matter comes mostly from air and water (NGSS 5-LS1-1). Students must interpret experimental evidence to support the claim that plants get materials chiefly from air and water, not soil. Multiple types of evidence prove that most plant matter comes from air and water, not soil: Van Helmont's famous willow tree experiment showed that a tree gained 164 pounds while the soil lost only 0.1 pound—the tree's mass couldn't have come from soil because the soil barely decreased; chemical analysis shows plants are 45% carbon (from CO₂ in air), 42% oxygen (from H₂O and CO₂), and 6% hydrogen (from H₂O)—totaling about 93% from air and water, with only about 6-7% from soil minerals; hydroponic experiments prove plants can grow without soil at all, showing soil is not the source of plant matter; when scientists remove carbon dioxide from air, plants stop growing, and when they add more CO₂, plants grow faster—this proves carbon from air is essential for building plant mass; all this evidence leads to one conclusion: plants get their matter chiefly from carbon dioxide in air and water, with small amounts of minerals from soil. Choice A is correct because it accurately states that plant matter comes mostly from air and water, with a small part from soil minerals, which matches the data showing 93 g from air and water and only 7 g from soil in a 100-gram plant, demonstrating the sources of plant atoms. Choice B fails because it claims soil minerals are the main source when the evidence shows only 7% from soil, representing the common misconception that roots absorb most mass from soil—but the evidence proves otherwise. To help students understand evidence for air and water as matter sources: Present the composition data: '45g carbon from air, 42g oxygen and 6g hydrogen from water—that's 93% not from soil!'; calculate percentages together: 'Only 7% from soil, so air and water are chief sources'; address that air can become solid, asking: 'What do the numbers prove?'
Plants grew well in water with dissolved minerals even without soil. What does this evidence show about where plant matter comes from?
Answer: primarily from air and water, with a small soil-mineral part This question tests the ability to use evidence to explain that plant matter comes mostly from air and water (NGSS 5-LS1-1). Students must interpret hydroponic evidence to support the claim that plants get materials chiefly from air and water, not soil. The hydroponic experiment provides powerful evidence: plants grew well in water with dissolved minerals, completely without soil. This proves that soil itself is not necessary for plant growth—only the small amount of minerals it normally provides, which can be dissolved in water instead. Choice B is correct because it states plant matter comes primarily from air and water, with a small soil-mineral part, which the hydroponic evidence demonstrates—plants thrived with just air, water, and dissolved minerals, proving these are the primary matter sources. Choice A fails because it claims matter comes 'from soil particles that become plant tissue,' but the hydroponic plants had no soil particles at all yet still built tissue, disproving this claim entirely. To help students grasp this evidence: Show lettuce growing in hydroponic systems at grocery stores. Ask: 'These plants have no soil touching their roots, yet they're growing. What does this prove about where plant matter comes from?' Emphasize that minerals (the only thing from soil that plants need) can be provided in water, but the bulk of plant matter—93%—comes from CO₂ and H₂O.
A student thinks plants are made mostly from soil because roots grow in dirt. But evidence shows soil mass barely changes as plants gain lots of mass, and plant dry mass is mostly carbon, oxygen, and hydrogen from CO₂ and water. Based on the evidence, where does most plant matter come from?
Answer: mostly from air and water, with only small amounts from soil This question tests the ability to use evidence to explain that plant matter comes mostly from air and water (NGSS 5-LS1-1). Students must interpret experimental evidence to support the claim that plants get materials chiefly from air and water, not soil. Multiple types of evidence prove that most plant matter comes from air and water, not soil: Van Helmont's famous willow tree experiment showed that a tree gained 164 pounds while the soil lost only 0.1 pound—the tree's mass couldn't have come from soil because the soil barely decreased; chemical analysis shows plants are 45% carbon (from CO₂ in air), 42% oxygen (from H₂O and CO₂), and 6% hydrogen (from H₂O)—totaling about 93% from air and water, with only about 6-7% from soil minerals; hydroponic experiments prove plants can grow without soil at all, showing soil is not the source of plant matter; when scientists remove carbon dioxide from air, plants stop growing, and when they add more CO₂, plants grow faster—this proves carbon from air is essential for building plant mass; all this evidence leads to one conclusion: plants get their matter chiefly from carbon dioxide in air and water, with small amounts of minerals from soil. Choice B is correct because it accurately states that plant matter comes mostly from air and water, with only small amounts from soil, which matches the evidence that soil mass barely changes while plants gain mass, and composition is mostly from CO₂ and water, countering the student's misconception. Choice A fails because it claims soil is the main source despite evidence of minimal soil change and 93% from air/water, representing the common misconception that roots in dirt mean matter from soil—but the evidence proves otherwise. To help students understand evidence for air and water as matter sources: Address misconceptions directly: 'Student thinks soil because of roots, but evidence shows soil doesn't decrease much'; present Van Helmont and composition: 'Mass gain from air/water, not soil'; emphasize evidence over intuition, asking: 'What do experiments and numbers prove?'
A class compared evidence: plants can grow without soil (hydroponics), and plants do not grow without CO₂. Based on the evidence, most plant matter comes mostly from what?
Answer: mostly from air (CO₂) and water, not mainly from soil This question tests the ability to use evidence to explain that plant matter comes mostly from air and water (NGSS 5-LS1-1). Students must interpret experimental evidence to support the claim that plants get materials chiefly from air and water, not soil. The class compared two key pieces of evidence: plants can grow without soil (hydroponics proves soil isn't necessary) but plants cannot grow without CO₂ (proving air is essential)—together, this evidence demonstrates that air and water, not soil, are the main sources of plant matter. The contrast between what's optional (soil) and what's required (CO₂/air) reveals the true sources. Choice C is correct because it states plant matter comes mostly from air (CO₂) and water, not mainly from soil, which matches what both pieces of evidence demonstrate—plants can live without soil but die without CO₂. Choice A fails because it claims matter comes mostly from soil when the evidence shows plants can grow completely without soil; this represents the misconception that roots in soil must mean soil provides the matter. To help students understand comparative evidence: Present the contrast: 'Plants can grow without soil (hydroponics works), but plants cannot grow without CO₂ (they die). What does this tell us about where matter comes from?' Use logic: 'If something is optional, it can't be the main source. If something is required, it must be important for building the plant.' Create a chart: 'With soil but no CO₂ = plant dies. Without soil but with CO₂ = plant lives. Which is the real source of matter?' Summarize: 'The evidence is clear—plants need CO₂ from air to build their bodies, but soil is just for minerals and support.'
In Van Helmonts results, the tree gained 164 lb but the soil lost only 0.1 lb. What does this evidence show about soil as the main source?
Answer: air and water provided most plant matter, not soil This question tests the ability to use evidence to explain that plant matter comes mostly from air and water (NGSS 5-LS1-1). Students must interpret experimental evidence to support the claim that plants get materials chiefly from air and water, not soil. Multiple types of evidence prove that most plant matter comes from air and water, not soil: Van Helmont's famous willow tree experiment showed that a tree gained 164 pounds while the soil lost only 0.1 pound—the tree's mass couldn't have come from soil because the soil barely decreased; chemical analysis shows plants are 45% carbon (from CO₂ in air), 42% oxygen (from H₂O and CO₂), and 6% hydrogen (from H₂O)—totaling about 93% from air and water, with only about 6-7% from soil minerals; hydroponic experiments prove plants can grow without soil at all, showing soil is not the source of plant matter; when scientists remove carbon dioxide from air, plants stop growing; when they add more CO₂, plants grow faster—this proves carbon from air is essential for building plant mass; all this evidence leads to one conclusion: plants get their matter chiefly from carbon dioxide in air and water, with small amounts of minerals from soil. Choice C is correct because it accurately states that air and water provided most plant matter, not soil, which matches what the evidence demonstrates—the tree gained 164 lb but soil lost only 0.1 lb, showing soil can't be the main source. Choice A fails because it claims soil provided most new matter when the evidence shows soil mass barely changed, representing the common misconception that plants get their matter from soil because we see plants growing in soil—but the evidence proves otherwise. To help students understand evidence for air and water as matter sources: Present Van Helmont's experiment as a mystery: 'The tree gained 164 pounds. The soil lost only 0.1 pound. Where did 164 pounds come from?' Students often guess soil until they see the numbers; emphasize: If the tree got 164 pounds from soil, the soil would weigh 164 pounds less—it doesn't—so the matter came from somewhere else; present the chemical composition evidence: 'Plants are made of carbon, hydrogen, and oxygen—where do these atoms come from? Carbon from CO₂ in air, hydrogen and oxygen from H₂O—that's 93% of the plant right there!'; use hydroponics as modern evidence: 'If plants got their matter from soil, they couldn't grow without soil—but they can—proving matter doesn't come mainly from soil'; teach the phrase: 'Plants don't eat soil—plants are made of air and water'; do the math together: 'If plants were made mostly of soil, the soil would disappear as the plant grows—does that happen? No—so plants must be made of something else—air and water'; watch for students who trust their intuition ('it must be soil') over evidence, or who don't understand that invisible gases (CO₂) have mass and can become solid plant matter; always return to evidence: 'What do the numbers show? What do experiments prove?'
Photosynthesis uses carbon dioxide from air and water to make sugar. Based on the evidence, plant matter comes mostly from what?
Answer: primarily from air (CO₂) and water, not mostly soil This question tests the ability to use evidence to explain that plant matter comes mostly from air and water (NGSS 5-LS1-1). Students must connect photosynthesis evidence to support the claim that plants get materials chiefly from air and water, not soil. Photosynthesis provides direct evidence: the process uses carbon dioxide from air and water to make sugar (C₆H₁₂O₆), which becomes plant matter. Since photosynthesis is how plants make their food and build their bodies, and it uses primarily CO₂ and H₂O as raw materials, this proves plant matter comes primarily from air and water. Choice A is correct because it states plant matter comes primarily from air (CO₂) and water, not mostly soil, which directly reflects what photosynthesis evidence shows—the main ingredients are CO₂ and H₂O, not soil. Choice C fails because while it mentions air and water, it incorrectly includes sunlight 'as matter'—sunlight provides energy for photosynthesis but doesn't become matter itself, unlike CO₂ and H₂O which provide actual atoms. To help students understand this evidence: Write the photosynthesis equation and circle the inputs that have mass (CO₂ and H₂O) versus energy (sunlight). Ask: 'Which ingredients have atoms that can become part of the plant?' This helps distinguish between matter sources (air and water) and energy sources (sunlight).
A class used the photosynthesis idea: plants take in carbon dioxide from air and water, then make sugars that build leaves, stems, and roots, while oxygen is released. This explains how air and water become plant material. Based on the evidence, plant matter comes mostly from what sources?
Answer: mostly from air (CO₂) and water, with only a little from soil This question tests the ability to use evidence to explain that plant matter comes mostly from air and water (NGSS 5-LS1-1). Students must interpret experimental evidence to support the claim that plants get materials chiefly from air and water, not soil. Multiple types of evidence prove that most plant matter comes from air and water, not soil: Van Helmont's famous willow tree experiment showed that a tree gained 164 pounds while the soil lost only 0.1 pound—the tree's mass couldn't have come from soil because the soil barely decreased; chemical analysis shows plants are 45% carbon (from CO₂ in air), 42% oxygen (from H₂O and CO₂), and 6% hydrogen (from H₂O)—totaling about 93% from air and water, with only about 6-7% from soil minerals; hydroponic experiments prove plants can grow without soil at all, showing soil is not the source of plant matter; when scientists remove carbon dioxide from air, plants stop growing, and when they add more CO₂, plants grow faster—this proves carbon from air is essential for building plant mass; all this evidence leads to one conclusion: plants get their matter chiefly from carbon dioxide in air and water, with small amounts of minerals from soil. Choice A is correct because it accurately states that plant matter comes mostly from air (CO₂) and water, with only a little from soil, which matches the photosynthesis evidence where plants use CO₂ and water to make sugars that build plant parts, showing air and water become plant material. Choice B fails because it claims soil turns directly into plant tissue when the evidence shows air and water are the chief sources, representing the common misconception that soil is the main matter source—but the evidence proves otherwise. To help students understand evidence for air and water as matter sources: Explain photosynthesis simply: 'Plants take CO₂ from air and water, make sugars—that's how air and water become leaves and stems'; use visuals to show atoms from CO₂ and H₂O forming plant molecules; emphasize evidence over intuition, asking: 'What do the processes prove?'
Scientists found plants are mostly carbon, hydrogen, and oxygen (about 93%), which come from CO₂ in air and water, while only about 7% comes from minerals in soil. Based on the evidence, plant matter comes chiefly from what?
Answer: chiefly from air and water, with only small amounts from soil minerals This question tests the ability to use evidence to explain that plant matter comes mostly from air and water (NGSS 5-LS1-1). Students must interpret experimental evidence to support the claim that plants get materials chiefly from air and water, not soil. The chemical composition evidence is definitive: plants are about 93% carbon, hydrogen, and oxygen (which come from CO₂ in air and water) and only about 7% minerals from soil—this proves mathematically that air and water are the chief sources of plant matter. The 93% to 7% ratio makes it clear which sources are primary. Choice A is correct because it states plant matter comes chiefly from air and water, with only small amounts from soil minerals, which precisely matches the 93% versus 7% evidence. Choice B fails because it claims minerals from soil are the largest part when the evidence shows minerals are only 7%; this represents the misconception that because minerals are important for plant health, they must make up most of plant mass. To help students understand percentage evidence: Make it visual: 'Imagine 100 marbles representing a plant—93 would be from air and water, only 7 from soil. Which is the chief source?' Emphasize the word 'chiefly': 'Chiefly means mainly or mostly—93% is definitely the main part!' Connect elements to sources: 'Carbon (45%) comes from CO₂ in air, hydrogen (6%) and oxygen (42%) come from water and CO₂—that's your 93%.' Address the misconception: 'Yes, minerals are important for plant health, but they're only 7% of the actual mass—like vitamins are important for humans but don't make up most of our body weight.'
Two bean plants grew similarly: one in soil, one in water with dissolved minerals (no soil). Based on the evidence, most plant matter comes from what?
Answer: mostly from air (CO) and water, not soil This question tests the ability to use evidence to explain that plant matter comes mostly from air and water (NGSS 5-LS1-1). Students must interpret experimental evidence to support the claim that plants get materials chiefly from air and water, not soil. Multiple types of evidence prove that most plant matter comes from air and water, not soil: Van Helmont's famous willow tree experiment showed that a tree gained 164 pounds while the soil lost only 0.1 pound—the tree's mass couldn't have come from soil because the soil barely decreased; chemical analysis shows plants are 45% carbon (from CO₂ in air), 42% oxygen (from H₂O and CO₂), and 6% hydrogen (from H₂O)—totaling about 93% from air and water, with only about 6-7% from soil minerals; hydroponic experiments prove plants can grow without soil at all, showing soil is not the source of plant matter; when scientists remove carbon dioxide from air, plants stop growing; when they add more CO₂, plants grow faster—this proves carbon from air is essential for building plant mass; all this evidence leads to one conclusion: plants get their matter chiefly from carbon dioxide in air and water, with small amounts of minerals from soil. Choice C is correct because it accurately states that plant matter comes mostly from air (CO₂) and water, not soil, which matches what the evidence demonstrates—plants grew similarly without soil in hydroponics, showing soil is not needed for most mass. Choice A fails because it claims soil is the main source when the evidence shows plants can grow without soil, representing the common misconception that plants get their matter from soil because we see plants growing in soil—but the evidence proves otherwise. To help students understand evidence for air and water as matter sources: Present Van Helmont's experiment as a mystery: 'The tree gained 164 pounds. The soil lost only 0.1 pound. Where did 164 pounds come from?' Students often guess soil until they see the numbers; emphasize: If the tree got 164 pounds from soil, the soil would weigh 164 pounds less—it doesn't—so the matter came from somewhere else; present the chemical composition evidence: 'Plants are made of carbon, hydrogen, and oxygen—where do these atoms come from? Carbon from CO₂ in air, hydrogen and oxygen from H₂O—that's 93% of the plant right there!'; use hydroponics as modern evidence: 'If plants got their matter from soil, they couldn't grow without soil—but they can—proving matter doesn't come mainly from soil'; teach the phrase: 'Plants don't eat soil—plants are made of air and water'; do the math together: 'If plants were made mostly of soil, the soil would disappear as the plant grows—does that happen? No—so plants must be made of something else—air and water'; watch for students who trust their intuition ('it must be soil') over evidence, or who don't understand that invisible gases (CO₂) have mass and can become solid plant matter; always return to evidence: 'What do the numbers show? What do experiments prove?'
A sealed terrarium let in only sunlight; the plant still grew for months using trapped air and recycled water, while soil stayed nearly the same. What does this evidence show about the source of plant matter?
Answer: mostly from air and water, because they can be reused to build tissues This question tests the ability to use evidence to explain that plant matter comes mostly from air and water (NGSS 5-LS1-1). Students must interpret experimental evidence to support the claim that plants get materials chiefly from air and water, not soil. The sealed terrarium experiment provides unique evidence: with only trapped air and recycled water available (no new inputs), the plant still grew for months while soil stayed nearly the same—proving the plant built new matter from air and water, not soil. If soil were the main source, it would have decreased as the plant grew, but it didn't. Choice B is correct because it states plant matter comes mostly from air and water, because they can be reused to build tissues, which matches what the evidence demonstrates—the plant grew using only the trapped air and recycled water. Choice A fails because it claims matter comes mostly from soil as the only solid material, when the evidence shows soil mass stayed nearly the same while the plant grew; this represents the misconception that only solid materials can provide mass. To help students understand terrarium evidence: Explain the closed system: 'Nothing new could get in—no fresh air, no new water, no added soil. Yet the plant grew!' Ask the key question: 'If the plant got bigger but the soil stayed the same, where did the new plant matter come from? It must be the air and water inside!' Emphasize recycling: 'The plant used CO₂ from air and water over and over to build new tissues—that's why it could keep growing.' Connect to conservation of mass: 'Matter can't appear from nowhere—it came from the air and water molecules being rearranged into plant molecules.'
Scientists found plants are about 93% made of carbon, oxygen, and hydrogen, which come from CO₂ in air and water. Only about 7% comes from soil minerals. This explains how air and water become plant material. What does this evidence support the claim that plants get their matter chiefly from?
Answer: mostly from air (CO₂) and water, not mainly from soil This question tests the ability to use evidence to explain that plant matter comes mostly from air and water (NGSS 5-LS1-1). Students must interpret experimental evidence to support the claim that plants get materials chiefly from air and water, not soil. Multiple types of evidence prove that most plant matter comes from air and water, not soil: Van Helmont's famous willow tree experiment showed that a tree gained 164 pounds while the soil lost only 0.1 pound—the tree's mass couldn't have come from soil because the soil barely decreased; chemical analysis shows plants are 45% carbon (from CO₂ in air), 42% oxygen (from H₂O and CO₂), and 6% hydrogen (from H₂O)—totaling about 93% from air and water, with only about 6-7% from soil minerals; hydroponic experiments prove plants can grow without soil at all, showing soil is not the source of plant matter; when scientists remove carbon dioxide from air, plants stop growing, and when they add more CO₂, plants grow faster—this proves carbon from air is essential for building plant mass; all this evidence leads to one conclusion: plants get their matter chiefly from carbon dioxide in air and water, with small amounts of minerals from soil. Choice A is correct because it accurately states that plant matter comes mostly from air (CO₂) and water, not mainly from soil, which matches the evidence showing 93% from carbon, oxygen, and hydrogen in CO₂ and water, and only 7% from soil, explaining how air and water become plant material. Choice B fails because it claims soil minerals make up most plant mass when evidence shows only 7% from soil, representing the common misconception that soil is the primary source—but the evidence proves otherwise. To help students understand evidence for air and water as matter sources: Show the percentages: '93% from air and water, only 7% soil— that's the proof!'; discuss how CO₂ atoms become plant parts; watch for intuition like 'air can't be solid,' and return to: 'What does the composition evidence prove?'
A 100 g dry plant is about 93 g from C, H, and O (air and water) and 7 g from soil minerals. What does this data demonstrate?
Answer: mostly from air (CO) and water, with little from soil This question tests the ability to use evidence to explain that plant matter comes mostly from air and water (NGSS 5-LS1-1). Students must interpret experimental evidence to support the claim that plants get materials chiefly from air and water, not soil. Multiple types of evidence prove that most plant matter comes from air and water, not soil: Van Helmont's famous willow tree experiment showed that a tree gained 164 pounds while the soil lost only 0.1 pound—the tree's mass couldn't have come from soil because the soil barely decreased; chemical analysis shows plants are 45% carbon (from CO₂ in air), 42% oxygen (from H₂O and CO₂), and 6% hydrogen (from H₂O)—totaling about 93% from air and water, with only about 6-7% from soil minerals; hydroponic experiments prove plants can grow without soil at all, showing soil is not the source of plant matter; when scientists remove carbon dioxide from air, plants stop growing; when they add more CO₂, plants grow faster—this proves carbon from air is essential for building plant mass; all this evidence leads to one conclusion: plants get their matter chiefly from carbon dioxide in air and water, with small amounts of minerals from soil. Choice C is correct because it accurately states that plant matter comes mostly from air (CO₂) and water, with little from soil, which matches what the evidence demonstrates—a 100 g plant has 93 g from C, H, O in air and water, and only 7 g from soil. Choice B fails because it states sources contribute equally when the evidence shows air and water provide 93% and soil only 7%, representing the common misconception that plants get their matter from soil because we see plants growing in soil—but the evidence proves otherwise. To help students understand evidence for air and water as matter sources: Present Van Helmont's experiment as a mystery: 'The tree gained 164 pounds. The soil lost only 0.1 pound. Where did 164 pounds come from?' Students often guess soil until they see the numbers; emphasize: If the tree got 164 pounds from soil, the soil would weigh 164 pounds less—it doesn't—so the matter came from somewhere else; present the chemical composition evidence: 'Plants are made of carbon, hydrogen, and oxygen—where do these atoms come from? Carbon from CO₂ in air, hydrogen and oxygen from H₂O—that's 93% of the plant right there!'; use hydroponics as modern evidence: 'If plants got their matter from soil, they couldn't grow without soil—but they can—proving matter doesn't come mainly from soil'; teach the phrase: 'Plants don't eat soil—plants are made of air and water'; do the math together: 'If plants were made mostly of soil, the soil would disappear as the plant grows—does that happen? No—so plants must be made of something else—air and water'; watch for students who trust their intuition ('it must be soil') over evidence, or who don't understand that invisible gases (CO₂) have mass and can become solid plant matter; always return to evidence: 'What do the numbers show? What do experiments prove?'
Van Helmont's experiment: tree gained 164 lb, soil lost 0.1 lb. Based on the evidence, where does most plant matter come from?
Answer: mostly from air (CO₂) and water, not soil This question tests the ability to use evidence to explain that plant matter comes mostly from air and water (NGSS 5-LS1-1). Students must interpret Van Helmont's experimental evidence to support the claim that plants get materials chiefly from air and water, not soil. Van Helmont's famous willow tree experiment provides clear evidence: the tree gained 164 pounds while the soil lost only 0.1 pound—if the tree's mass came from soil, the soil would have lost 164 pounds, not 0.1 pound. This massive difference (164 pounds gained vs 0.1 pound lost) proves the tree's matter must have come from somewhere else—air and water. Choice B is correct because it accurately states that plant matter comes mostly from air (CO₂) and water, not soil, which matches what Van Helmont's evidence demonstrates. Choice A fails because it claims matter comes mostly from soil, but the evidence shows soil lost only 0.1 pound while the tree gained 164 pounds—the math doesn't support soil as the main source. To help students understand this evidence: Present it as a mystery—'The tree gained 164 pounds but the soil lost only 0.1 pound. Where did 163.9 pounds come from?' Have students do the math themselves to see that soil cannot be the answer, then reveal that invisible CO₂ from air becomes solid plant matter through photosynthesis.
Two bean plants grew similarly: one in soil, one in water with minerals (no soil). Based on the data, what can you conclude?
Answer: mostly from air and water, with little from soil This question tests the ability to use evidence to explain that plant matter comes mostly from air and water (NGSS 5-LS1-1). Students must interpret experimental evidence comparing soil-grown and hydroponic plants to support the claim that plants get materials chiefly from air and water, not soil. The hydroponic experiment provides crucial evidence: plants grew similarly whether in soil or in water with dissolved minerals (no soil at all). If soil were the main source of plant matter, the hydroponic plant couldn't grow without it—but it did grow, proving plant matter doesn't come mostly from soil. Choice C is correct because it states that plant matter comes mostly from air and water, with little from soil, which the hydroponic evidence clearly demonstrates—plants can thrive without soil as long as they have air, water, and small amounts of minerals. Choice A fails because it claims matter comes mostly from soil 'because roots need dirt,' but the evidence shows roots don't need dirt at all—the hydroponic plant grew fine without any soil. To help students understand this evidence: Set up a simple hydroponic demonstration where students can see plants growing in water. Ask: 'If plants were made mostly of soil, could they grow without soil?' When they see healthy hydroponic plants, the answer becomes obvious—plants must be getting their matter from something other than soil, namely air and water.
Plants were grown in chambers: normal air (0.04% CO₂) grew normally, enriched CO₂ (0.08% CO₂) grew faster and larger, and no CO₂ caused plants to die. What does this evidence show about where plant matter comes from?
Answer: mostly from air (CO₂) and water, not mainly from soil This question tests the ability to use evidence to explain that plant matter comes mostly from air and water (NGSS 5-LS1-1). Students must interpret experimental evidence to support the claim that plants get materials chiefly from air and water, not soil. Multiple types of evidence prove that most plant matter comes from air and water, not soil: Van Helmont's famous willow tree experiment showed that a tree gained 164 pounds while the soil lost only 0.1 pound—the tree's mass couldn't have come from soil because the soil barely decreased; chemical analysis shows plants are 45% carbon (from CO₂ in air), 42% oxygen (from H₂O and CO₂), and 6% hydrogen (from H₂O)—totaling about 93% from air and water, with only about 6-7% from soil minerals; hydroponic experiments prove plants can grow without soil at all, showing soil is not the source of plant matter; when scientists remove carbon dioxide from air, plants stop growing, and when they add more CO₂, plants grow faster—this proves carbon from air is essential for building plant mass; all this evidence leads to one conclusion: plants get their matter chiefly from carbon dioxide in air and water, with small amounts of minerals from soil. Choice C is correct because it accurately states that plant matter comes mostly from air (CO₂) and water, not mainly from soil, which matches the CO₂ chamber evidence where removing CO₂ stopped growth and adding it increased growth, showing carbon from air is key for plant mass. Choice A fails because it claims soil minerals are the main source when the evidence shows CO₂ from air is essential, representing the common misconception that gases like CO₂ can't contribute to solid matter—but the evidence proves otherwise. To help students understand evidence for air and water as matter sources: Present the CO₂ experiment: 'Plants died without CO₂ but grew faster with more—proving air's carbon builds plant mass'; emphasize: 'CO₂ is invisible but has mass that becomes part of the plant'; watch for students who think air can't add mass, and return to: 'What do experiments prove about CO₂?'
Two bean plants grew for 4 weeks: Plant A in soil grew 12 inches, and Plant B in water with dissolved minerals (no soil) grew 11 inches and stayed healthy. The data demonstrate plants can grow without soil. Based on this evidence, where does most plant matter come from?
Answer: mostly from air and water, with small amounts from minerals This question tests the ability to use evidence to explain that plant matter comes mostly from air and water (NGSS 5-LS1-1). Students must interpret experimental evidence to support the claim that plants get materials chiefly from air and water, not soil. Multiple types of evidence prove that most plant matter comes from air and water, not soil: Van Helmont's famous willow tree experiment showed that a tree gained 164 pounds while the soil lost only 0.1 pound—the tree's mass couldn't have come from soil because the soil barely decreased; chemical analysis shows plants are 45% carbon (from CO₂ in air), 42% oxygen (from H₂O and CO₂), and 6% hydrogen (from H₂O)—totaling about 93% from air and water, with only about 6-7% from soil minerals; hydroponic experiments prove plants can grow without soil at all, showing soil is not the source of plant matter; when scientists remove carbon dioxide from air, plants stop growing, and when they add more CO₂, plants grow faster—this proves carbon from air is essential for building plant mass; all this evidence leads to one conclusion: plants get their matter chiefly from carbon dioxide in air and water, with small amounts of minerals from soil. Choice C is correct because it accurately states that plant matter comes mostly from air and water, with small amounts from minerals, which matches the hydroponic evidence where Plant B grew nearly as well without soil, showing soil is not the main source of plant matter. Choice A fails because it claims soil is the main source when the evidence shows plants can grow without soil, representing the common misconception that plants get their matter from soil because we see them planted in it—but the evidence proves otherwise. To help students understand evidence for air and water as matter sources: Use hydroponics as modern evidence: 'If plants got matter from soil, they couldn't grow without it, but they can—proving matter comes mainly from air and water'; emphasize: 'The plant in water with minerals grew healthy, so soil isn't needed for most mass'; teach that invisible gases like CO₂ have mass and become solid plant matter, and always ask: 'What do experiments prove?'
A sealed terrarium plant grows for months; water and CO₂ are recycled inside. What does this evidence support about plant matter?
Answer: mainly from air and water, with little from soil minerals This question tests the ability to use evidence to explain that plant matter comes mostly from air and water (NGSS 5-LS1-1). Students must interpret terrarium evidence to support the claim that plants get materials chiefly from air and water, not soil. The sealed terrarium provides unique evidence: with no new soil added and water/CO₂ recycling inside, the plant still grows for months. This proves the plant builds new matter from recycled CO₂ and water, not from consuming soil—if soil were the main source, the limited soil would be depleted and growth would stop. Choice B is correct because it states plant matter comes mainly from air and water, with little from soil minerals, which the terrarium evidence demonstrates—the plant keeps growing using recycled air and water, needing only small amounts of soil minerals. Choice A fails because it claims matter comes mainly from soil with 'dirt trapped inside,' but in a sealed system, if plants consumed soil as their main matter source, the soil would disappear as the plant grew—yet it doesn't. To help students understand this evidence: Create a sealed bottle terrarium and mark the soil level. After months of growth, show that the soil level hasn't dropped despite new leaves and stems. Ask: 'If the plant ate the soil to grow, where did the soil go?' This demonstrates that growth comes from recycled air and water, not soil consumption.

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