7th: Topic Test Review

You probably use the term heat many times a day. As an example, when you cook, dinner, you heat your dinner on a hot stove. When you place a piece of cool metal in the sun, it is heated by the sun’s energy. Why is heat the correct term to use in these examples?

• They show that when objects are touching, they are the same temperature.

• They show that heat flows from something warmer to something cooler.

• They indicate that heat is created to raise the temperature of something.

• They indicate that the kinetic energy of the particles decreases when something is heated.

When a boy and his friends arrive at a barbecue, they offer to help their friend cook. They place meat and vegetables from the refrigerator onto the hot grill. When the food is cooked and taken off the grill, it is at a much higher temperature than it was before it was cooked. Which statements are true about the food? Choose the two that apply.

• The kinetic energy of the food particles increased, causing the food temperature to rise.

• The thermal energy of the food increased.

• The kinetic energy of the food particles decreased, causing the food temperature to rise.

• The thermal energy of the food decreased.

A student likes to attend football games, no matter how cold and snowy the weather becomes. She is going to a game on a very cold day and takes along a hand warmer. She activates it and tucks it into the glove she is wearing. She holds her hands together, and before long, her hands are warm. Which best describes how her hands were warmed?

• Heat was transferred by conduction, resulting in an increase in kinetic energy.

• Heat was transformed by convection, resulting in the conservation of energy.

• Thermal energy was transferred by currents, resulting in an increase in kinetic energy.

• Heat was transformed by radiation, resulting in an increase in kinetic energy.

You are camping, and it is time to build a campfire. You gather logs and stack them loosely, and then you add small twigs and leaves to make the fire easy to light. As you sit by the fire, the logs burn bright in the darkness, and you feel the heat coming toward you. Which of these statements are true about the amount of energy transformed in the camp fire? Choose the two that apply.

• The Law of Conservation of Energy applies to these transformations.

• The chemical energy in the logs is lost during the transformation.

• The fire is hotter than the logs were, so energy is gained in this transformation.

• The amount of heat and light energy released equals the amount of chemical energy that is burned.

A new home had a wooden floor put down in cool weather. As the weather became warmer, the floor started to buckle, rising up in the middle of the floor. The floor was fixed by trimming the edges of the floor so that there was a space between the flooring and the wall. Choose the response that best explains why this helped to make the floor flat again.

• The particles in the floor decrease in thermal energy in warm weather, decreasing the kinetic energy of its particles and making it expand. Trimming it gave it room to expand.

• The particles in the floor increase in thermal energy in warm weather, increasing the kinetic energy of its particles and making it expand. Trimming it gave it room to expand.

• The particles in the floor decrease in thermal energy in warm weather, decreasing the kinetic energy of its particles and making it contract. Trimming it gave it room to contract.

• The particles in the floor increase in thermal energy in warm weather, increasing the kinetic energy of its particles and making it contract. Trimming it gave it room to contract.

Which of these statements describes visible light? Choose the two that apply.

• Red light has a longer distance between wave crests than blue light.

• Yellow light has a shorter distance between wave crests than green light.

• Blue light has a longer distance between wave crests than red light.

• Blue light has a shorter distance between wave crests than orange light.

• Orange light has a shorter distance between wave crests than violet light.

Erika visits the Grand Canyon with her family. When she shouts near the edge, she can hear her voice echo throughout the canyon. Which statement describes why Erika hears her echo?

• The sound was loud.

• The sound waves travelled in a vacuum.

• The sound waves reflected off the canyon walls.

• The sound waves bent as they travelled into the canyon

Describe how light and sound waves are affected when they move from air to water.

• Light and sound waves are absorbed by the water.

• Light and sound waves change speed when they move from air to water and look as if they are bent.

• Light and sound waves are reflected off the surface of the water and bounce off in the equal, but opposite angle.

• Light and sound waves move through the water with no change.

Bella is designing a model of a longitudinal sound wave for her science classroom.

Which of the following pieces of information should Bella include in her model? Choose the two statements that apply.

• Sound must travel through a material to transfer energy.

• Sound must travel through a vacuum to transfer energy.

• Rarefaction and compression are properties of longitudinal waves.

• Crests and troughs are properties of longitudinal waves.

Henry ties a rope to the handle of a door. He moves the rope up and down to make waves.

The highest areas on the wave are called _______.

• compressions

• crests

• rarefactions

• troughs