Science - Unit P Day 10

Science - Unit P Day 10

By KELLY COOTS

Multiple Choice

Which of the following is an example of electrical energy being changed into motion?

• a fan inside a computer

• the screen of a laptop

• the speaker in the ceiling

• a teapot boiling on a stove

​Electrical energy can be changed into heat, light, and sound, as well as the energy of motion (mechanical energy.) The heat produced by electrical energy can be used for many things. For example, that heat can be used to cook our food. It can also be used to heat our water: we use hot water to cook with, to make drinks like coffee and tea, and we use hot water in our sinks and our baths. Electrical energy also provides heat for our homes on cold days. We use heat to clean and dry our clothes when we do laundry. These are some of the many ways we use the heat produced by electrical energy every day.

Electrical Energy Transforms​

Multiple Choice

Which of the following gadgets best shows the transformation of energy from electrical to mechanical with the correct reasoning?

• A light bulb because electricity is being used to create light and heat.

• A fan because electricity is being used to spin the blades of the fan.

Multiple Choice

Two students place three ice cubes in a glass of water that was at room temperature. Which of the following scenarios would best describe the results of the investigation?

• Energy from the water will transfer to the ice cubes, causing the ice to melt.

• Cold from the ice cubes will transfer to the water, causing the water to cool.

​Most machines and tools that we use to make heat use plugs instead of batteries. That is because changing electricity into heat uses a lot of electricity. Electricity flows through metals very well. Metals are good conductors of electricity, as well as heat. That is why wire is made from copper: copper is soft enough to bend easily, and conducts electricity very well. Some materials do not conduct electricity at all: rubber, for example, is used to cover the copper wires because rubber prevents the flow of electricity. Rubber is an insulator.

Multiple Choice

___________________ are materials that ALLOW heat and electricity to move easily through them.

• Conductors

• Insulators

Multiple Choice

Which particles move the FASTEST and have more thermal energy?

• Cold Particles

• Hot Particles

Multiple Choice

How does thermal energy move?

• When objects touch.

• When objects stay still.

Multiple Choice

______________ are materials that RESIST the flow of heat or thermal energy.

• Conductors

• Insulators

​Some materials conduct electricity, but not very well. Electricity will flow through these materials, but because they are poor conductors (but not so poor as to be insulators) these materials produce heat when electrical energy passes through them. This is why some lightbulbs produce a lot of heat: the materials they use produce both heat and light.

Multiple Choice

Why are metals useful for making electrical wire?

• Metals do not bend.
• Metals hold much heat.
• Metals are insulators.
• Metals are conductors.

Multiple Choice

Gloves help keep your hands warm in winter because:

• They are conductors of heat.
• They are fuzzy.
• They are conductors of electrical energy.
• They are insulators.

Multiple Choice

Thermal energy travels...

• Hot to cold
• Cold to hot
• Inside to outside
• Outside to inside

​When you turn on your stove, the first thing that happens is that a circuit closes and allows electricity to flow from the outlet in the wall to the stovetop. You will be able to observe the stovetop starting to glow red as it heats up: as electricity passes through the material in the stovetop, electrical energy is changed into heat, and some light.

Multiple Choice

This circuit has a battery, buzzer, and switch.
When the switch is closed the buzzer will sound because -

• the switch gives energy to the battery
• the buzzer is made of special plastic
• the wires are cooled by the surrounding air
• electricity can flow in a complete path

Multiple Choice

Which of the following can work as an energy source?

• Battery
  
• Light bulb
• Wire
  
• All of them

​You would find the same kind of heating element in a hot water heater, a coffee maker, a clothes dryer, and a hair dryer. All of these tools change electrical energy into heat that we can use.

Multiple Choice

Which of the following is not an example of electrical energy being changed in to sound?

• listening to music on headphones

• morning announcements over the speakers

• exploding fireworks

• the music playing on the speakers at PE