Random 1
What does it mean if a ball is just sitting at the highest top of the hill?
A) Less potential energy
B) Greatest potential energy
B) Greatest potential energy.
For thousands of years, people have used the power of water to do work. One example is a hydroelectric dam. Hydroelectric dams, like the one shown below, use water to generate electricity.
Which of the following best explains why people can use water to generate energy?
A. Water flowing downhill has energy.
B. Water contains a lot of heat energy.
C. Water is a good conductor of electricity.
D. Water easily absorbs energy from the Sun.
A. Water flowing downhill has energy.
In a hydroelectric dam moving water flows downhill and is used to turn turbines, start a generator, and create electricity.
Shayna and Mike are making a list of electrical appliances that people use in their homes. Here are four things on their list. Which of the objects was designed to convert electrical energy into useful heat energy?
A. fan
B. lamp
C. radio
D. toaster
D. toaster
Electrical energy is transformed into heat energy. The toaster used electrical energy that is transformed to heat energy to toast the bread.
Katie and her family are watching a fireworks display at an outdoor Fourth of July celebration. The fireworks store chemical energy, and when they are set off, they give off two forms of energy: light and which of the following?
A. electrical
B. mechanical
C. solar
D. sound
D. sound
Fireworks change chemical energy into light and sound energy when they are set off.
Rodney is taking a shower. The temperature of the water coming out of the showerhead is 40 °C (104 °F).
What might Rodney predict is the air temperature inside the closed shower stall?
A. 25 °C (77 °F).
B. 40 °C (104 °F).
C. 50 °C (122 °F).
D. 55 °C (131 °F).
B is correct because the temperature of the shower stall should be the same or nearly the same as the temperature of the water coming out of the showerhead, which is 40 °C (104 °F).
Cora has a homework assignment to create a list of examples in which energy can be shown to cause a change.
Which of the following should NOT be included in Cora's assignment?
A. the Earth revolves around the Sun
B. a man stands on the surface of the Earth
C. a satellite orbits the Earth at a constant speed
D. a meteorite falls through the Earth's atmosphere
B. a man stands on the surface of the Earth
Energy has the ability to cause motion or create change. A man standing (not in motion) has only stored energy. The examples shown in the box are all forms of mechanical energy (energy of motion).
On hot summer days, Rudy uses a fan in his bedroom. What energy transformation most helps the fan to do its job when he turns it on?
A. electrical energy into heat energy
B. energy of motion into heat energy
C. electrical energy into energy of motion
D. energy of motion into electrical energy
C. electrical energy into energy of motion
Electrical energy is converted to energy in motion (mechanical energy) which moves the fan’s blades.
Solar power is a technology that relies on a renewable energy resource. Solar power changes energy from the Sun into a form of energy that can be used to heat our homes and run household appliances.
What form of energy must solar energy be changed into in order to run household appliances?
A. chemical
B. electrical
C. light
D. thermal
B. electrical
Light energy from the sun is captured by solar panels and converted into electrical energy to run household appliances.
Stacey has a glass of water. She measures the temperature of the water to be 30 °C (86 °F). She adds ice cubes to the water. After 10 minutes, which of these is most likely the temperature of the water?
A. 50 °C (122 °F)
B. 40 °C (104 °F)
C. 30 °C (86 °F)
D. 20 °C (68 °F)
D is correct because the melted ice would cool the water down, and 20 °C (68 °F) is colder than the original temperature of 30 °C (86 °F).
Jose is making this chart of examples of actions in which energy has caused change, as shown below. He accidentally added one that should NOT have been listed. Which action should Jose have left off his chart?
A. dropping a book
B. holding a cup
C. rolling a ball
D. opening a door
B. holding a cup
Energy has the ability to cause motion or create change. Holding a cup has only stored energy (not in motion). The examples shown in the box are all forms of mechanical energy (energy of motion).
When Zan sat down to do her homework, she turned on a desk lamp. What energy transformation occurs when a desk lamp is turned on?
A. light energy into electrical energy
B. light energy into energy of motion
C. electrical energy into light and heat energy
D. electrical energy into light and energy of motion
C. electrical energy into light and heat energy
Energy transformation occurs when electrical energy is converted into light energy in a light bulb. The filament in the bulb uses the electric charges to create light, which also gives off heat energy.
In many electrical factories, fossil fuels are burned to boil water and generate steam. This steam is then used to help generate electricity. What type of energy is given off by the fossil fuels and used to boil the water?
A. chemical energy
B. heat energy
C. light energy
D. sound energy
B. heat energy
When burning fossil fuels chemical energy is turned into heat energy (steam) to power a generator to make electricity.
The Sun is the source of heat in a desert. The body temperatures of reptiles like this lizard change with their environment.
Which statement describes how the heat of the sand affects the lizard’s body as it comes out of the shade?
A. Its body temperature increases.
B. Its body temperature decreases.
C. Its body temperature stays the same.
D. Its body temperature decreases, then increases.
A is correct because the lizard’s body temperature would be warmer in the hot sand than in the shade.
Hugh is looking out his window and notices leaves moving in the trees across the street. Which of the following explains where the leaves get the energy required to cause this movement?
A. Gravity pulls the leaves back and forth.
B. The Sun radiates heat into the leaves.
C. The leaves undergo photosynthesis.
D. Wind transfers energy to the leaves.
D. Wind transfers energy to the leaves.
Wind energy can be described as air in motion. When the wind blows its energy is transferred to the leaves causing them to move back and forth.
Bill’s mom likes to listen to the radio in the kitchen while she is making dinner. What energy transformation does she notice when she turns on the radio?
A. electrical energy into heat
B. light into chemical energy
C. sound energy into electrical energy
D. electrical energy into sound energy
D. electrical energy into sound energy
Energy transformation occurs when electrical energy is converted into sound energy in a radio. Wires in the radio use the electrical to pick up the audio waves to produce sound.
Bobbie is playing with his radio-controlled car by using a handheld remote box. What type of energy is being used to power Bobbie's car?
A. chemical energy
B. electrical energy
C. heat energy
D. mechanical energy
B. electrical energy
In a remote control chemical energy is exhibited through the use batteries and converted to electrical energy.
Joaquin places a thermometer in a glass of water. He places a second thermometer
in a glass filled with sand. Both thermometers start at the same temperature.
Which describes what will most likely happen after the beakers sit in the sunlight for 30 minutes?
A. The temperature in the beaker with sand will decrease.
B. The temperature in the beaker with water will not change.
C. The temperatures in both of the beakers will increase.
D. The temperatures in both of the beakers will decrease.
Answer C is correct because both beakers should experience a rise in temperature after sitting in the sunlight for 30 minutes.
Shawn's teacher asks him to think of several actions from soccer practice that show how energy causes changes.
Which of the examples below shows a change caused by applying energy?
A. kicking the ball
B. sitting on the ball
C. resting his foot on the ball
D. holding the ball in his hands
A. kicking the ball
Energy has the ability to cause motion. When a soccer ball is kicked mechanical energy is applied and causes the ball to be set into motion.
Batteries store energy in the form of chemical energy. The chemical energy can be converted into electrical energy, which can be used to operate a pencil sharpener.
Which diagram best shows the energy conversions that help the boy sharpen the pencil?
A. electrical →chemical →heat
B. chemical →electrical →sound
C. chemical →electrical →motion
D. motion →electrical →chemical
C. chemical → electrical → motion
Energy transformation occurs when chemical energy is turned into electrical energy then is converted into mechanical in a pencil sharpener. The chemicals in a battery create electric charges that flow through a wire to a motor that spins in order to sharpen a pencil.
Amber visits a theme park that has a roller coaster that travels upside down. Which of the following is the best explanation for why the roller coaster car stays in contact with the track when it travels upside down?
A. The track and car are held together by a series of strong magnets.
B. The car has large amounts of thermal energy that binds it to the track.
C. The car has chemical energy that resists the effect of gravity when it is upside down.
D. The car has mechanical energy and is fast enough that gravity cannot pull the car down.
D. The car has mechanical energy and is fast enough that gravity cannot pull the car down.
Mechanical energy is energy gained by the physical movement in position of an object. As the rollercoaster moves fast on the track, it overcomes the force of gravity.