This question tests the skill 3-PS2-4, which involves identifying design problems that can be solved using magnets. Magnets are useful because they can attract certain metal objects like steel or iron, work at a distance without touching, hold things in place without glue or tape, and separate magnetic materials from non-magnetic ones. In this problem, cans are mixed in a bin and steel ones need sorting, and magnets are a good solution because they selectively attract steel while ignoring other materials like aluminum or plastic. The correct answer works because it explains that magnets attract steel, allowing steel cans to stick and be separated, applying the correct magnetic property practically. The distractors fail because they misunderstand magnetism, like thinking magnets attract all metals, melt plastic, or make cans float, which doesn't accurately solve the sorting problem. To teach this, first identify what the problem needs, such as separating based on material properties. Then, match the magnetic property of selective attraction to the need, test with actual magnets on different cans, and consider the materials to understand why only steel will be attracted.

This question tests the skill 3-PS2-4: Identify design problems solvable with magnets. Magnets are useful because they attract certain metal objects like steel or iron, can work at a distance, hold things without glue or tape, and separate magnetic from non-magnetic materials. The problem involves finding steel washers hidden in sawdust in a workshop, and magnets are a good solution because they can attract the washers while ignoring the non-magnetic sawdust for easy separation. Choice A works because a magnet pulls out the steel washers from the sawdust, applying the separation property of magnets practically and efficiently. Choices B, C, and D fail because B assumes sawdust is magnetic which it's not, C is impractical with melting, and D thinks magnets attract plastic which they don't. To teach this, identify what the problem needs, like separating metal from non-metal materials. Then match the magnetic attraction to the need, test with actual magnets in sawdust mixtures, and consider which materials like steel will be attracted.

This question tests the skill 3-PS2-4: Identify design problems solvable with magnets. Magnets are useful because they attract certain metal objects like steel or iron, can work at a distance, hold things without glue or tape, and separate magnetic from non-magnetic materials. The problem involves moving a toy car without touching it or using batteries, and magnets are a good solution because they can pull or push the car at a distance if properly set up with magnetic parts. Choice B works because placing a magnet on the car and using another to attract or repel it moves the car without contact, applying the properties of magnetic attraction or repulsion practically. Choices A, C, and D fail because A uses wind not magnets, C assumes plastic wheels are magnetic which they're not, and D is unrelated to magnetism. To teach this, identify what the problem needs, like moving an object without direct contact. Then match magnetic attraction or repulsion to the need, test with actual magnets on toy cars, and consider if the car's materials can interact with magnets.

This question tests the skill of identifying design problems that can be solved with magnets (3-PS2-4). Understanding magnetic properties is crucial for solving sorting problems: magnets specifically attract iron and steel, do not attract aluminum or plastic, can quickly identify magnetic materials, and enable efficient separation of mixed materials. The problem involves sorting mixed recyclables, and knowing which materials are magnetic makes the task simple and fast. Option A is correct because it accurately states that magnets attract iron and steel, explaining why steel cans stick to magnets - this fundamental property allows quick identification and separation of steel cans from other materials. Option B fails because it incorrectly claims magnets attract plastic, while Options C and D present completely false information about magnets melting metals or only working in water. When using magnets for sorting, remember the key rule that magnets only attract iron and steel (not all metals), test unknown items with a magnet to classify them, and use this selective attraction to separate magnetic from non-magnetic materials efficiently - recycling centers use powerful electromagnets based on this exact principle.

This question tests the skill of identifying design problems that can be solved with magnets (3-PS2-4). Magnets have properties that make them useful for holding and displaying: they can stick to iron and steel surfaces, hold objects without damaging them, can be easily moved and repositioned, and work without adhesives like tape or glue. The problem is finding a way to hang notes on a refrigerator without using tape, and magnets are ideal because refrigerators have steel doors that magnets stick to strongly. Option C is correct because it recognizes that small magnets can hold papers against the metal fridge door - the magnet sticks to the steel surface and pins the paper between the magnet and the door. Option D fails because it suggests the magnet attracts the paper itself, but paper is not magnetic - the magnet works by sticking to the metal fridge and holding the paper in place. To use magnets for holding problems, identify metal surfaces where magnets will stick (like refrigerators, filing cabinets, or metal boards), choose magnets strong enough to hold your items, and remember that the magnet attaches to the metal surface, not to non-magnetic materials like paper.

This question tests the skill of identifying design problems that can be solved with magnets (3-PS2-4). Magnets provide useful properties for closure mechanisms: they can attract each other or metal surfaces, create holding force without mechanical parts, work silently and smoothly, and maintain their strength over time without wearing out. The problem is keeping a cabinet door closed that tends to swing open, and magnetic catches offer an elegant solution. Option A is correct because it uses a magnetic catch system where one part attaches to the door and another to the cabinet frame - when the door closes, the magnetic attraction pulls it shut and holds it securely. Option D fails because it misunderstands magnetic poles - having same poles face each other would create repulsion that pushes the door open, not closed. When designing magnetic closures, use opposite poles for attraction (or magnet to metal), position magnets so they align when the door closes, and choose magnet strength appropriate for the door's weight - magnetic catches are widely used in furniture because they're simple, reliable, and adjustable.

This question tests the skill of identifying design problems that can be solved with magnets (3-PS2-4). Magnets have properties that make them excellent for finding and separating materials: they attract iron and steel objects, work through non-magnetic materials like sawdust, can pull magnetic items out of mixtures, and make sorting faster than manual methods. The problem is finding steel washers hidden in sawdust, and magnets solve this efficiently because steel washers are strongly magnetic while sawdust is not. Option A is correct because it uses a magnet to attract the steel washers through the sawdust and lift them out - the magnetic force passes through the wood particles to reach the metal washers. Option B fails because it incorrectly claims that sawdust is magnetic - wood and wood products are not attracted to magnets, which is actually why this method works so well. To use magnets for finding hidden metal objects, move the magnet slowly through the material, remember that magnetic force works through non-magnetic substances, and use a strong magnet for better results - this technique is commonly used in workshops to recover dropped metal parts from debris.

This question tests the skill 3-PS2-4, which involves identifying design problems that can be solved using magnets. Magnets are useful because they can attract certain metal objects like steel or iron, work at a distance without touching, hold things in place without glue or tape, and separate magnetic materials from non-magnetic ones. In this problem, a cabinet door swings open and needs to stay closed, and magnets are a good solution because a magnetic catch can pull and hold the door shut securely. The correct answer works because it uses a small magnet catch to hold the door closed, applying magnetic attraction in a practical and safe way to solve the issue. The distractors fail because they don't use magnets, like kicking or painting, or misuse them on non-magnetic wood from a distance, which is impractical. To teach this, first identify what the problem needs, such as holding something closed without force. Then, match the magnetic property of holding in place to the need, test with actual magnetic catches on a door, and consider the materials to ensure the magnet can attract and secure them.

This question tests the skill of identifying design problems solvable with magnets (3-PS2-4). Magnets can attract metal objects like steel and iron, work at a distance, and help separate magnetic materials from non-magnetic ones like plastic, making them perfect for sorting tasks. The problem involves separating steel cans from plastic in recycling, and magnets solve this because they only attract the steel cans while leaving plastic behind. Answer A works correctly because it uses magnets to identify and pull out only the steel cans, applying the property that magnets attract ferrous metals but not plastic. Answer B fails because color doesn't indicate material type, C misunderstands magnetism (plastic is not magnetic), and D doesn't use magnets at all and won't effectively separate materials. Teaching strategies include having students test different materials with magnets to discover which are attracted, practice sorting mixed materials, and understand that magnets provide a quick way to separate magnetic from non-magnetic items.

This question tests the skill of identifying design problems solvable with magnets (3-PS2-4). Magnets can attract metal objects like steel through non-magnetic materials like sawdust, allowing separation of magnetic items from non-magnetic debris without touching or sorting by hand. The problem involves finding steel washers hidden in sawdust, and magnets solve this perfectly because they attract only the steel washers while ignoring the wood sawdust. Answer A works correctly because a magnet passed over or through the sawdust will attract and lift out only the steel washers, leaving the sawdust behind. Answer B misunderstands magnetism (sawdust/wood is not magnetic), C incorrectly states magnets can't pick up metal, and D doesn't address finding the washers. When teaching, demonstrate magnetic separation by mixing steel objects with sand or sawdust, show how magnets attract through the mixture, and emphasize that this property makes magnets useful for separating and finding metal objects in various materials.