Machines Get Hot!

Warm-up

• Do they feel cold, warm, damp, or sticky? • What will happen if hands are rubbed

together? • TIMER! • What happened?• “The observation: The movement of your

hands caused heat!”• Do you feel more heat?

Is my Hypothesis true?

Hypothesis

• I predict that when I rub my hands together they will get stick together because they are sticky.

Actual Result

• My hands got warm as I rubbed them together.

Results

My hypothesis was incorrect because….

I said my hands would stick together since they were sticky. However, my hands did not stick together. Instead they got warm when I rubbed them together.

Instruction Sheet

• Rub a penny with wool for ten seconds.• Rub a penny with half a sheet of paper for ten

seconds.• Touch the penny, touch the wool, and touch the

paper.• What happened to the penny, wool, and paper?• Write the question and your observations in

your science journal.

Warm-up Continued

• What happens when two objects are rubbed against one another?

• “One possible answer is: Heat is produced when two objects are rubbed together.”

Lesson

• What machines produce heat?

• Types of machines that produce heat:

Mechanical machines

Electrical machines

Definitions

• Mechanical machines—those machines that have moving parts, and the parts can be put into motion by a person.

• Electrical machines—those machines that have moving parts, but work by the use of a motor.

Back

Different Machines

Mechanical Machines

Mechanical machines are machines that have moving parts, and the parts can be put into motion by a person.

Electrical Machines

Electrical machines are those that have moving parts, but work by the use of a motor.

Lesson Continued

• What happened when the grinding gears rubbed together?

• On a scale of 1 to 5, how hot were the grinding gears of the pencil sharpener when you touched them?

• What happened to the temperature of the water after the blender was turned on?

Assignment for Number 1

• If you have the number 1 on the top of your page, you will make the final decision of what the machine is—mechanical or electrical. Put the name of the machine in the first or second column, depending on what your group’s answer is. However, before you write down the name of your machine in its proper column, make sure you have talked with your entire group first and have come up with the answer together.

Assignment for Number 2

• If you have the number 2 on the top of your page, you will make the final decision on whether the machine produces heat or light. Put a check mark in the third or fourth column of the handout, depending on your group’s answer. However, before you write the check mark, make sure you have talked with your group and come up with the answer together.

Assignment for Number 3

• If you have the number 3 on the top of your page, you will make the final decision of how hot your group thinks the machine is on a scale of 1 to 5. Also, make sure that you have talked with your group before you circle the final answer.

Assignment for Number 4

• If you have the number 4 on the top of your page, your job is to make sure that everyone in your group, including yourself, have completed their worksheet by putting the information talked about in the group in the proper columns. Also, make sure your group, including yourself, glues the completed Things are Hating Up handout into your science journal.

Application

• What kind of machines do you use in your home?

• Are the machines you use mechanical or electrical?

• Use these questions to explore the machines in your home, write your observations in your science journals, and share your findings with your family.