Definitions
Thermal Expansion
Thermal expansion happens when something gets bigger (expands) because it's heated. The heat makes the particles move faster and take up more space.
Describe what happens to the particles when matter melts.
Melting is the process of a solid changing into a liquid when heat is applied.
The heat will cause the particles inside the solid to move. This will cause the particles to spread out and flow into the bottom of the container they are held in.
Explain why a bike tire might be flat if you have it in the garage during winter.
The particles get colder and closer together, so there is less pressure on the tire.
Describe the properties of particles in a solid.
Name the steps of the Scientific Method in order.
Question
Hypothesis
Materials
Procedure
Observations
Conclusion
Thermal Contraction
Thermal contraction is the opposite of thermal expansion. It's when something gets smaller (contracts) because it's cooled. The cold slows the particles down and they take up less space.
Describe what happens to the particles when matter evaporates.
This is the process through which a liquid turns into a gas. An everyday example of evaporation is the drying of wet clothes. Evaporation typically happens when the substance is heated.
The door in Abby’s house is harder to open in the summer than in the winter. It feels like it is sticking or hitting on the door frame. Why is that?
The particles in the door heat up and expand, making the door physically bigger and causing it to stick.
Describe the properties of particles in a liquid.
Move around more than solid but not as much as gas, somewhat spread apart.
Explain how potholes form.
When temperatures drop, water that seeps into tiny cracks in the asphalt freezes. As this happens, the water molecules slow down and arrange themselves into a crystalline structure, which takes up more space than liquid water. This expansion applies pressure from within the asphalt, causing the cracks to widen.
Volume
Volume is how much space something takes up. If you pour water into a cup, the amount of space the water occupies is its volume.
Describe what happens to the particles when matter condenses.
This is the reverse process of evaporation, where a gas turns back into a liquid. An example of this process can be seen when dew forms on a cold surface on a hot day.
Melanie just broke a ceramic bowl. She took it out of the fridge and removed the food from it. Then she tried washing it with really hot water. Unfortunately, the bottom of the bowl fell right through! What happened?
The bottom of the bowl was much hotter than the side of the bowl. When the particles expanded on only part of the bowl, it pushed on the parts that didn't expand causing it to break.
Describe the properties of particles in a gas.
Moving around a lot, really spread out.
How is water different than other substances when it freezes?
Mass
Mass is a measure of how much matter is in something. It's not the same as weight, which can change if you go somewhere like the moon.
Describe what happens to the particles when matter sublimates (sublimation).
This process involves a substance transitioning from a solid state directly to a gas, skipping the liquid state. An example is the "disappearance" of dry ice (solid carbon dioxide) when left at room temperature.
Explain why train tracks have to be made with a gap in between.
What is it called when a solid turns into a gas directly?
Sublimation.
Explain how a thermometer works.
A thermometer works because of thermal expansion. Thermometers have a liquid inside, usually mercury or alcohol. These liquids will expand and shrink (contract) when they are heated or cooled.
Density
Density is how tightly packed the particles in an object are. If particles are close together, the object is dense. If they're spread out, it's less dense.
Describe what happens to matter during deposition.
The reverse of sublimation, deposition is when a gas changes directly into a solid without becoming a liquid first. An example of this can be seen when frost forms on a window on a cold day.
Explain why powerlines hang instead of being pulled tight across.
They fluctuate in tempurature so they will expland and contract based on the tempurature. If they were pulled tight and contracted, they would snap.
What is the fourth type of matter called? (hint: fire)
Plasma
What are the three types of variables in an experiment?
Manipulated, responding and controlled.