Lesson 5: OpenSciEd 6.2 Thermal Energy

Why do droplets form on the outside of a cold pitcher?

• Because water vapor in the air condenses on the cold surface

• Because lemonade leaks through the pitcher

• Because droplets escape from ice cubes in the pitcher

• Because the pitcher releases moisture

If you add food coloring to water inside a pitcher, what color would you expect the droplets on the outside to be?

• They would be colorless.

• They would be the same color as the food coloring.

• They would be a mix of clear and food coloring.

• They would be tinted slightly.

What conclusion can you draw from observing water droplets forming on an empty cup?

• Water in the air condenses on cold surfaces.

• Cups spontaneously create water droplets.

• Only rain can create water droplets.

• The cup releases stored water.

Which claim about the droplets is most supported by evidence?

• Regina’s claim that the droplets come from the air outside.

• Sarah’s claim that droplets are leaking lemonade.

• Michael’s claim that droplets are from melting ice.

• None of the claims are supported.

What should you conclude if the colored water inside does not change the color of droplets outside?

• Water outside is from the air, not the cup content.

• Water inside the cup is evaporating too quickly.

• Food coloring does not mix well.

• The cup absorbs the food coloring.

Why might an empty chilled plastic cup also collect droplets on the exterior?

• The air contains moisture that condenses on the cold surface.

• The plastic attracts water molecules.

• There is hidden water inside the plastic.

• The chilled cup absorbs moisture from its surroundings.

If droplets on a chilled cup have no added color, what does it prove?

• The water originated from the air.

• The cup walls are permeable.

• The colored water from inside leaked.

• Ice has absorbed the coloring.

Which experiment setup best confirms the source of water droplets on the outside of a cup?

• Adding food coloring to the water inside the cup

• Heating the cup and observing droplets

• Covering the cup with plastic wrap

• Shaking the cup periodically

What should you conclude if the droplets on the outside of the cup are clear despite the colored water inside?

• The droplets are colored.

• The droplets are clear.

• The droplets are a mix of colors.

• The droplets are opaque.

How can the structure of solid particles explain why water cannot leak through the walls of the cup?

• Solid particles are tightly packed, preventing leakage.

• Solid particles vibrate and create gaps for water to pass.

• Solid particles dissolve when in contact with water.

• Solid particles can move aside to let water pass.