8th Grade Science FOCUS on Acheivement Week 4

Walter is making a list of energy transformations. He needs at least 1 example in which electrical energy is transformed to mechanical.

• turning on a radio

• turning on a stove

• turning on a light bulb

• turning on a ceiling fan

When a ball bounces, it had changing amounts of potential and kinetic energy. Eventually the ball will stop bouncing. Why does it stop?

• The ball's energy gets used up each time it bounces

• the mass of the ball is too small to allow it to continue its own motion

• the ball's energy gets transferred to other energy types like heat and sound that won't help it bounce

• the pull of gravity is stronger than the energy of the ball, which makes the ball slow down to a stop

An electric can opener that plugs into the wall to work, converts electrical energy into which of the following?

• chemical

• mechanical

• potential

• radiant

When you bake a cake in an oven a chemical change that involved energy occurs. Which statement describes the AMOUNT of energy in the oven while the cake is baking.

• the total amount of energy increases because the oven gets hot

• the total amount of energy decreases because it changes into matter

• the total amount of energy stays the same, but changes from one form to another

• the total amount of energy will either increase or decrease, depending on how much cake batter there is

Polly is explaining the Law of Conservation of Energy to her friend. She is using a light bulb as an example. Which statement best explains this law?

• Electrical energy is destroyed to create light and thermal energy

• Potential energy is used to create electrical energy and release light and thermal energy

• Electrical energy is transformed into light, and thermal energy is released to the surroundings

• Electrical energy created by the light bulb is converted into light and thermal energy and used up by the surroundings

Many countries use Wind Farms to generate electricity. Unfortunately, when the mechanical energy from the wind is transformed into electricity, some energy is lost as heat. Which best describes how mechanical energy, electrical energy and heat are related above?

• Mechanical + Electrical + Heat = 0

• Electrical + Heat = Mechanical

• Electrical + Mechanical = Heat

• Mechanical + Heat = Energy

Sasha drops some of her ice cream on a hot sidewalk. Which of the following correctly describes what happens next?

• The temp of the sidewalk and the ice cream both remain unchanged

• the temp of the ice cream increases as it send cold to the sidewalk

• heat from the sidewalk is transferred to the ice cream, increasing the temp of the ice cream

• cold from the ice cream is transferred to the sidewalk, decreasing the temp of the sidewalk

Erin places some ice cubes into freshly made tea that is still quite warm. Which of the following correctly describes what happens next?

• some of the heat from the tea is transferred to the ice and causes them to melt

• the temp of the ice remains the same as the temp of the tea drops

• the cold from the ice is transferred into the tea and causes the cubes to warm up and melt

• heat is transferred between the ice and the tea, which causes the temp of the tea to increase

Eric places some room temperature strawberries into his freezer. Which of the following correctly describes what happens to the strawberries?

• the heat from the berries is transferred to the freezer and causes the strawberries to freeze

• some of the cold from the freezer is transferred to the strawberries and causes the strawberries to freeze

• the temp of the freezer remains the same as the temp of the strawberries decreases

• heat is transferred from the freezer to the berries and causes the temp of the berries to decrease

Vinnie places his cold drink on the roof of a hot car. Which of the following correctly describes what happens next?

• the temp of the drink increases as it sends cold into the hot metal of the car

• heat is transferred from the car into the drink and increases the temp of the drink

• cold is transferred from the drink into the metal of the car, decreasing the temperature of the roof

• the temperature of the area under the drink decreases until it is the same temperature as the cold drink