1. The Microwave Oven
Introduction

2. The Microwave Oven Form of energy that travels like radio waves
Magnetron (MAG-nuh-trahn) tube turns electricity into microwaves
Microwaves are distributed throughout the oven by a stirrer blade which is a fan like device
Microwaves bounce off the oven’s walls and floor until they are absorbed by food
Microwave energy is reflected from metal but will pass through glass, paper, and plastic

3. Invention of the Microwave
All started one morning in 1945
Dr. Percy Spencer
Scientist
Working in his lab
Felt heat on his hands
Microwaves
Placed a chocolate bar where the heat was located
Within seconds the chocolate melted
This was the beginning of the idea of using microwaves in cooking

4. Parts of the Microwave Door Metal wire mesh
Allows you see but the microwave can not get out

5. Parts of the Microwave Magnetron Tube
Changes electricity to microwave energy
Looks like a radio or TV tube
Should last for 3,000 hours of use
(10 years)

6. Parts of the Microwave Cavity The inside of the microwave
Stainless steel
Glass tray on the bottom

7. Parts of the Microwave Fan What you hear when the microwave is running
Helps cool the magnetron tube

8. Parts of the Microwave Stirrer Looks like a fan
Moves the microwave around the cavity

9. Parts of the Microwave Wave Guide
A pipe that carried the microwaves from the magnetron tube to the cavity

10. Power Levels 100% 50% Tube is producing microwaves the entire time
in one minute the magnetron tube is only working for 30 seconds

11. Hot Spots
Microwave are not sent through the stirrer evenly throughout the microwave
The turntable will help with even cooking

12. Experiment with Hot Spots
1.Place a Piece of wax paper on the bottom of the microwave covering the entire surface
2.Place 5 marshmallows on the wax paper
One in each corner
One in the center
3. Turn Microwave to 100% Power
4. If the stirrer is sending out even microwave the marshmallow will all grow at the same rate and size
5.Marshmallows that get big first are the hot spots in your microwave

13. Microwavable Containers
Microwave will pass through
Glass
Plastic
Paper
Wood
Straw

14. Microwaveable Containers
DO NOT USE METAL IN THE MICROWAVE

15. Standing Time Food continues to cook when removed from the microwave
Cook foods until just almost done
Remove
Let stand until they are finished cooking

16. Cook Times
Most foods cook in the microwave in 1/3 of the time

17. Help with food cooking
Stir Foods
Place in circular formation