States of Matter
Compare solids and liquids in terms of shape and volume.
Solids: definite shape & volume; Liquids: definite volume but take shape of container
Explain why a cold soda can get water droplets on the outside when left out on a hot day.
Condensation: water vapor cools and turns to liquid
Why is steel magnetic but aluminum is not?
Steel contains iron, which is magnetic; aluminum does not.
What tool and unit do scientists use to measure mass?
Balance, grams/kilograms
Which tool is best for measuring the volume of a liquid?
Graduated Cylinder
Why does a piece of wood float in water while a rock sinks?
Wood is less dense than water; rock is more dense.
Name a material that is a conductor and explain why it is used in cooking pots.
Metal like copper or aluminum, because they transfer heat quickly
Water boils at 100°C (212°F). What change in state happens at this temperature, and what is the new state?
Liquid → Gas, water vapor
What happens to the particle movement when a liquid is cooled into a solid?
Particles slow down, vibrate less, and lock into fixed positions.
A teacher puts a magnet near a pile of objects: paperclip, copper wire, nickel coin, wooden stick. Which are attracted, and why?
Just the paperclip, because it contains magnetic metal.
A student measures the same rock on Earth and on the Moon. Will the mass change? Why or why not?
No, mass stays the same because the amount of matter doesn’t change.
A box has a length of 5 cm, width of 3 cm, and height of 2 cm. What is its volume?
5 × 3 × 2 = 30 cm³
Oil floats on water. Which has greater density?
Water is less dense than oil and therefore floats.
Why is plastic used to cover electrical wires?
Plastic is an insulator and protects people from electric shocks.
Describe how the motion of particles is different in solids, liquids, and gases.
Solids: vibrate in place; Liquids: move/slide past each other; Gases: move freely and spread out
A student melts chocolate and then freezes it again. Explain why this is only a physical change.
No new substance is formed; only state changes.
Explain how magnets are useful in separating mixtures.
Magnets can attract certain metals and separate them from non-magnetic materials.
How is mass different from weight?
Mass = amount of matter, same everywhere; Weight = force of gravity on an object, changes with location
Explain how you would measure the volume of an irregular object like a rock.
Water displacement in a graduated cylinder
An object floats with half of it above water and half below. What does this tell you about its density compared to water?
The object’s density is equal to about 1 g/mL, very close to water’s density, which is why it floats halfway submerged.
A student tests three spoons (metal, wood, and plastic) in hot water. Predict which will heat up fastest and why.
Metal spoon, because it is a conductor of heat.
Explain why ice floats on water even though both are the same substance.
Ice is less dense than liquid water because its particles spread out when frozen.
Compare evaporation and boiling. How are they similar and different?
Both are liquid → gas changes. Boiling occurs at a specific temperature, whereas evaporation can happen at any temperature on the surface.
What metals are magnetic?
Iron, Cobalt, Nickel, and Steel
Two blocks look the same size, but one has a greater mass than the other. Explain what this means about their particles.
The block with more mass has more matter packed into the same space — its particles are more tightly packed or heavier, meaning it has higher density.
A balloon and a marble are placed in a container. The balloon has greater volume. Does this mean it has more mass? Explain.
Not always—volume is space taken up, mass is matter; a balloon may have less mass but larger volume.
Explain why relative density is important in designing ships.
Ships are made so their overall density is less than water, allowing them to float even though they are made of metal.
Explain why insulated houses stay warmer in the winter and cooler in the summer.
Insulators trap heat inside in winter and block outside heat in summer.
Dry ice changes directly from a solid to a gas without becoming a liquid. What is this process called, and why does it happen?
Sublimation — it happens when a solid gains enough energy for its particles to break free directly into a gas.
A student heats a pan of water on a stove. Explain how heat moves from the stove burner to the pan, then to the water.
Heat transfers by conduction (burner → pan), then conduction/convection (pan → water). Water circulates as convection currents form.
Why would a magnet be able to pick up a steel nail but not a copper penny? Explain in terms of the properties of metals.
Steel contains iron, which has magnetic domains where electrons align to create a magnetic field. Copper does not have these properties and is non-magnetic.
A block has a mass of 24 g and a volume of 8 cm³. What is its density?
24 ÷ 8 = 3 g/cm³
A rock is dropped into a graduated cylinder filled with 50 mL of water. The water rises to 65 mL. What is the rock’s volume? If the rock’s mass is 45 g, what is its density?
Volume = 65 – 50 = 15 mL. Density = 45 ÷ 15 = 3 g/mL.
A block of unknown material has a mass of 60 g and volume of 30 cm³. Will it float in water?
Density = 60 ÷ 30 = 2 g/cm³, which is greater than water’s density of 1, so it sinks
A cooler keeps drinks cold for hours at a picnic. Explain why it works, using the ideas of conductors, insulators, and heat transfer.
The cooler is made of insulating materials (like Styrofoam) that slow the transfer of heat from the hot outside air to the cooler inside. This prevents conduction and convection from warming the drinks quickly.