HW Practice Set 4.1 - Energy Conversions

Two bowling balls are rolling down two bowling lanes. The white ball is traveling at a speed of 14 miles per hour. The black ball is traveling at 12 miles per hour.

• The black ball has more energy than the white ball.

• The white ball has more energy than the black ball.

• The black ball has a greater ability to create energy than the white ball.

• The white ball has a greater ability to create energy than the black ball.

Answer explanation

The faster an object is moving, the more energy it has. The white ball is moving faster than the black ball.

Jasmine's town relies on energy from wind to power lights in her school. Her friend Jose lives in another town that does not have a lot of wind. He doesn’t understand how wind can make the lights stay on in her school. Which of the following is the best explanation Jasmine can provide to Jose about how this works?

• Motion energy is converted to thermal energy.

• Motion energy is transferred to solar energy and then to electrical energy.

• Motion energy is created by solar energy.

• Motion energy is converted into electrical energy.

Answer explanation

Motion energy (from wind) is converted into electrical energy (powers the school’s lights). 

Mona lives in Arizona where it is sunny for many days of the year. Her family drives a car that is powered only by the sun. Which of the following are benefits of driving a solar car versus one that runs only on fossil fuels? Select all that apply.

• Solar energy produces less pollution than fossil fuels.

• Solar energy is a renewable source of energy.

• Solar energy is a non-renewable source of energy.

• Solar energy is more expensive than fossil fuels.

Answer explanation

Solar energy produces less pollution, and therefore, is a cleaner source of energy, than fossil fuels. 

Solar energy is a renewable source of energy, so it will continue to provide sunlight for a long time as we continue to use it. 

Tags

NGSS.HS-ESS3-4

NGSS.HS-ETS1-3

Desmond was given a solar cooker. It takes 50 minutes to cook food when placed in direct sunlight. He wants to test variations of this design to find one that can cook the food faster. He changed one variable at a time to test a variety of designs. He also noted the cost that was necessary to make each change. The data are in the table. 

Based on Desmond’s criteria, which design should he choose? 

• 1

• 2

• 3

• 4

Answer explanation

Cooking food the fastest was the main criteria. 40 minutes was the fastest time. It says that Desmond noted the cost, but cost was not part of the criteria.

A science student is using a solar cooker to investigate how energy moves from one place to another. Which of the following explains one way that energy is transferred?

• Heat energy moves from the box to the sun.

• Light energy moves from the food to the sun.

• Light energy moves from the reflector to the sun.

• Heat energy moves from the dark bowl to the food.

Answer explanation

Dark colors absorb heat. Light colors reflect heat. Energy is absorbed by the dark bowl and moves to the food.

The image above shows a blender mixing ingredients for a milkshake. Which of the following best explains the energy in this example?

• Electrical energy is transferred from the surrounding air.

• Electrical energy is transferred to the motion energy.

• Motion energy is transferred to the light energy.

• Motion energy is created as it transfers to the electrical energy.

Answer explanation

Electrical energy (from the wall socket) is transferred (converted) to the motion energy as the blender’s blades move. 

Tags

NGSS.MS-PS3-5

Every time Sonya and Sasha go camping, their lights don't last very long when it turns dark out. They want this light so they can read at their campsite. They brainstorm ways they can design a solar powered light that will last the longest and solve their problem. What steps should they take first to find the most effective solution?

• Test only the design that is the cheapest to make.

• Ask their friends which design they think will work best.

• Test different designs and choose the design that works the best.

• Test only the design that is the easiest to make.

Answer explanation

Testing different designs will show which ones work the best (engineering design process).

Tags

NGSS.MS-ETS1-1

NGSS.MS-ETS1-2

NGSS.MS-ETS1-3

A town relies on water from a dam nearby to provide electricity. Explain the energy in this example.

• Motion energy from the water is transformed into electrical energy.

• Motion energy from the water is transformed into sound energy.

• Electrical energy from the water is transformed into motion energy.

• Electrical energy from the water is transformed into electrical energy.

Answer explanation

Motion energy from the moving water is converted into electrical energy that the town uses. 

Tags

NGSS.MS-PS3-5

The illustration shows a lamp that is plugged into an outlet and powered on. How does this lamp use energy?

• Light energy converts to electrical energy.

• Heat energy is transformed into electricity.

• Electrical energy causes motion energy.

• Electrical energy is converted to light and heat energy.

Answer explanation

Electrical energy is converted to light energy and heat (thermal energy).

A student drops a book to the floor to investigate how energy changes into sound. When the book hits the floor, it makes a loud sound. How was the sound produced?

• Electrical energy was produced when the book hit the floor. This produced a sound.

• Energy of motion from the falling book was converted to heat. The heat produced a sound.

• Electrical energy was produced as the book fell to the floor, which caused a sound to be produced.

• Energy of motion from the falling book was transferred to the floor, which caused a sound to be produced.

Answer explanation

The motion energy from the book transfers to the ground, resulting in the production of a sound. 

Tags

NGSS.MS-PS2-1

NGSS.MS-PS3-5