Physical or Chemical?
This change happens when water boils and becomes a gas. Is this a physical change or a chemical change? Explain briefly.
Physical change — boiling is a change of state; particles separate but the substance (water) is the same.
f a toy car moves at a steady speed in a straight line, are the forces on it balanced or unbalanced? Why?
Balanced — steady speed, no net force causing acceleration.
Light from a flashlight is what form of energy?
Light energy.
What state of matter has a definite shape and definite volume?
Solid
Define "mass" in one simple sentence for a classmate.
Mass is the amount of matter in an object.
Baking soda and vinegar fizz when mixed. Is that a physical or chemical change? What is one piece of evidence that supports your answer?
Chemical change — fizzing (gas released) indicates a new substance forms (carbon dioxide) and/or a chemical reaction.
A soccer ball is sitting still until someone kicks it. Which type of force caused the motion to change?
Unbalanced force (push) changes the motion.
When you rub your hands together and they get warm, which form of energy increased?
Thermal (heat) energy
Describe what happens to particles when a solid becomes a liquid.
Particles gain energy, move more, and separate enough to flow past each other — solid becomes liquid.
Define "force" and give a classroom example.
Force is a push or pull; example: pushing a desk across the floor.
A metal paperclip is bent into a new shape. Is that physical or chemical? Name one physical property that lets you know.
Physical change — shape changed but the substance is still metal; physical property: malleability.
You push a book across a table and it slows down and stops. Name two forces involved and explain how they affect the book’s motion.
Push (applied force) and friction (opposes motion); push starts motion, friction slows it.
A stretched rubber band snaps and launches a paperclip. Which forms of energy changed during the process? Name at least two.
Elastic potential energy (stretched band) → kinetic energy (moving paperclip); some energy may become thermal and sound.
When water freezes, do particles gain or lose energy? Explain how this relates to particle movement.
Particles lose energy; they move less and arrange into a more fixed structure.
Match the term to its meaning — write the correct term (mass, volume, gravity, friction) for this definition: "The pull that Earth makes on objects toward its center."
Gravity
A leaf changes color and breaks down into compost over months. Is this a physical or chemical change? Give one reason.
Chemical change — breakdown and new substances (decomposition), color change and new smell/texture are evidence.
A skateboarder rolls down a ramp and then rolls on flat ground. Describe how gravity and friction affect the skateboarder’s speed on the ramp vs. the flat.
Gravity pulls skateboarder down ramp increasing speed; friction and air resistance slow them on flat ground.
Explain how energy changes when food is eaten and then used to run or play.
Chemical energy in food → kinetic energy for movement and thermal energy; respiration changes chemical energy to usable forms.
Explain how the conservation of matter applies when water evaporates from a puddle. How could you collect evidence that matter is conserved?
Evaporation moves water into the air as gas; collect and condense the vapor to show mass conserved or measure total mass of closed system before and after.
Explain the difference between "chemical change" and "physical change" using one example for each.
Chemical change makes new substances (e.g., rusting); physical change only changes form (e.g., melting ice).
Salt dissolves in water. Is dissolving salt a physical or chemical change? Describe how you could show the amount of matter is conserved in this process.
Dissolving salt is a physical change. Evaporate the water and the salt reappears; measure mass before dissolving and after (including container) to show conservation.
Describe how you know whether a force is balanced or unbalanced. Give one example.
A force is balanced if it does not change an object's motion. The object will stay still or keep moving at the same speed in in a straight line. (A book sitting on a table)
A force is unbalanced if it does change an object's motion. It makes it speed up, slow down, or change direction. (A soccer ball starts moving when someone kicks it.)
Describe the transfer of energy in the collision of two balls. How could you measure the transfer of energy?
Example: collision of two balls — transfer of kinetic energy; measure speed before and after using a stopwatch and distance.
Dissolving salt is a physical change. Evaporate the water and the salt reappears; measure mass before dissolving and after (including container) to show conservation.
Dissolved particles spread among water particles; measure total mass of solution in a closed container to show conservation.
Use these words in one sentence that makes sense: particle, energy, conserve, reaction.
Example sentence: "Particles keep moving and energy can change form, but we must conserve matter even after a reaction."