17. Two samples of pure water are mixed with food coloring. One sample is red, and the other is blue. When the two water samples are combined, the red water floats on top of the blue water. Which statement best explains this result? (1 point)

Question

• The red water is warmer and is less dense.
O The blue water is colder and is less dense.
• The red water is colder and is more dense.
•The blue water is warmer and is more dense.

Answer 1

The correct statement that best explains why the red water floats on top of the blue water is:

• The red water is warmer and is less dense.

When liquids of different temperatures are combined, the warmer liquid tends to be less dense and will float above the colder, denser liquid. In this case, the warmer red water being less dense causes it to float over the colder blue water.

Answer 2

18. Which investigation would best show the transfer of heat energy without any type of matter as a medium? (1 point)
• an investigation of radiation using a current within a fluid
an investigation of conduction through movement of particles within a
solid
• an investigation of conduction using collisions between particles
• an investigation of radiation using electromagnetic waves

Answer 3

The investigation that would best show the transfer of heat energy without any type of matter as a medium is:

• an investigation of radiation using electromagnetic waves.

Radiation is a method of heat transfer that does not require matter or a medium; it can occur through a vacuum. Electromagnetic waves, such as infrared radiation, carry heat energy and can transfer it across empty space.

Answer 4

19. Convection ovens cook food more evenly than a standard thermal oven. Which statement explains how a convection oven works?
(1 point)
• Hot air is transferred through direct molecule contact.
Hot air is transferred through density differences when hot air rises and cool air sinks.
Hot air is transferred through density differences when cool air rises and hot air sinks.
• Hot air is transferred when heat radiates from a thermal burner.
20. People use oven mitts to avoid getting burns when moving hot metal pans while cooking. Which physical property of the metal pan requires the use of an oven mitt when it is hot? (1 point)
• High thermal conductivity
• Low thermal conductivity
• High solubility
• Low magnetism

Answer 5

For question 19: The statement that explains how a convection oven works is:

• Hot air is transferred through density differences when hot air rises and cool air sinks.

In a convection oven, the hot air circulates, allowing for more even cooking as the rising hot air pushes cooler air down, creating a continuous flow of heat.

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For question 20: The physical property of the metal pan that requires the use of an oven mitt when it is hot is:

• High thermal conductivity.

Metal pans conduct heat very well, which means they can become extremely hot when heated. Using oven mitts helps prevent burns when handling them.