Physics
Explainer: What is friction?
The force of friction always acts to slow things down. It depends on just two factors: the surfaces and how hard they press together.
By Trisha Muro
MS-PS2-2
Plan an investigation to provide evidence that the change in an object's motion depends on the sum of the forces on the object and the mass of the object.
More Stories in MS-PS2-2
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PhysicsScientists Say: Force
When an object experiences a force, its change in motion — or acceleration — depends on its mass.
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TechYou might someday ‘wallpaper’ your bedroom with this loudspeaker
This thin, flexible and lightweight loudspeaker could reduce noise in loud spaces. It also might enable listeners to experience sound in new ways.
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PhysicsWhen dominoes fall, how fast the row topples depends on friction
Two types of friction help determine how quickly a line of dominoes collapses, computer modeling shows.
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PhysicsScientists Say: Inertia
Inertia is the tendency of objects to resist changes in their motion.
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AnimalsOrb-weaving spiders use their webs like external eardrums
Scientists discover that orb-weaving spiders listen with their legs, detecting sound vibrations that travel through their silken webs.
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SpaceExplainer: All about orbits
A handful of rules can describe the route some object repeatedly takes around another in space. Calculating that path, however, can be quite complex.
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PhysicsExplainer: The fundamental forces
Four fundamental forces control all interactions between matter, from the smallest subatomic particles to the largest structures in the universe.
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TechRobots made of cells blur the line between creature and machine
Scientists are using living cells and tissue as building blocks to make robots. These new machines challenge ideas about robots and life itself.
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PhysicsA new device uses atoms’ quantum weirdness to peer underground
Quantum sensors like this one could monitor magma beneath volcanoes or uncover archaeological artifacts.