Solids, liquids and gases as moving particles
Grade 8 Science Worksheet - Building Confidence
Circle the best answer, or write your answer on the line.
The hot plate adds energy at a steady rate. Ari heats ice on a hot plate. From the first reading of 0 °C to the last, how many minutes pass?
The freezer takes energy away at a steady rate. Bo puts a cup of water in a freezer. From the first reading of 0 °C to the last, how many minutes pass?
Longer wiggle lines mean faster vibrating. Kira compares two models of one solid. Which statement does the table support?
- The two boxes are at one temperature, since both show particles in neat rows
- Box B is warmer, since heat has added new particles between the rows
- Box B is warmer, and its particles have swelled, since heat makes particles grow
- Box B is warmer, and it is still a solid since its particles stay in rows
Longer motion lines mean faster particles. Luz compares two sealed boxes of gas. Which box pushes harder on its walls? Use the table.
- Box B, since faster particles hit the walls harder and more often
- Box A, since slower particles stay near the walls and press longer
- Box B, since heating has added more particles to the box
- Neither, since both boxes hold 8 particles and the pushes are equal
Read this first
Melting and boiling points at sea level (reference data)
substance melts at (°C) boils at (°C) Mercury −39 357 Oxygen −219 −183 Lead 327 1749 Milo reads the table. At 20 °C, which substance has particles that are close together and sliding past each other?
- Oxygen, since 20 °C is above its melting point of −219 °C
- Lead, since 20 °C is below its boiling point of 1749 °C
- Mercury and lead, since metals are liquids once they are warmer than a cold room
- Mercury, since 20 °C is above its melting point and below its boiling point
At −100 °C, which substance in the table is a liquid, Noah?
- Ethanol, since −100 °C is above −114 °C and below 78 °C
- Bromine, since −100 °C is below its boiling point of 59 °C
- Bromine, since it is a liquid at room temperature and stays liquid when cold
- Nitrogen, since −100 °C is above its melting point of −210 °C
At 90 °C, what state is each substance in, Pia?
- Both are liquids, since 90 °C is above the melting point of each substance listed
- Water is a liquid and ethanol is a gas, since 90 °C is above ethanol's boiling point
- Both are liquids, since 90 °C is below the boiling point of water, which is 100 °C
- Water is a gas, since 90 °C is close to 100 °C, and ethanol is a liquid since it melts at −114 °C
A drop of dye spreads faster in warm water than in cold water. Which explanation fits the particle model, Ren?
- Warm water particles shrink as they heat up, so the dye particles can slip between them sooner and spread
- Dye particles stop moving in cold water, so they cannot spread until the water has warmed up
- Warm water particles move faster, so they bump the dye particles around and spread them sooner
- Warm water holds more particles than cold water, so more of them are there to push the dye along
A sealed balloon of air shrinks in a freezer. Which explanation fits the particle model, Tala?
- The cold shrinks each air particle, so the same particles take up less room inside the balloon and it gets smaller
- The cold destroys some of the air particles, so less air is left inside the balloon and it gets smaller
- Air particles stop moving in the cold, so they fall to the bottom of the balloon and it collapses
- Slower air particles hit the wall less often and less hard, so it shrinks until the pushes balance
Zee says a solid's particles do not move, so a solid has no thermal energy. Which reply fits the particle model?
- A solid's thermal energy is stored in the empty gaps between its particles, not in the particles themselves
- Solid particles slide past one another like those in a liquid, so they move enough to hold thermal energy
- Solid particles vibrate in place, so they have thermal energy, and warming makes them vibrate faster
- A solid's particles stay still, and its thermal energy comes from its mass, not from any particle motion