Making Plasma in Your Microwave

Create Spaceship Fuel in Your Microwave

 How many states of matter are there?  Most of were taught there were three of them: Solid, Liquid and Gas.

Actually, there are two more.  The fourth state of matter is called “plasma” (Note - this is NOT the kind of plasma doctors talk about that's associated with blood.  Same word, totally different meaning).  Plasma is the stuff that engines for spaceships in sci-fi shows like Star Trek supposedly use.

Today, you’re going to learn how to safely make plasma in your microwave!  It’s WAY cool.

Here’s all you need:

• A Microwave oven
• A grape
• A Knife, with adult help
• A Plate

(Pretty easy so far, right?)

If you’re not near a computer,  here are the general steps.  It’s just a lot easier to see exactly how to cut the grape, and what the plasma looks like when you get it right on video, so do check it out.

Here are the steps…

Be careful with this!! This experiment uses a knife AND a microwave, so you're playing with things that slice and gets things hot. If you’re not careful you could cut yourself or burn yourself. Please use care!

1. Carefully cut the grape almost in half. You want to leave a bit of skin connecting the two halves, but not too much or it won’t work well.

2. Open the grape like a book. In other words, so that the two halves are next to one another still attached by the skin.

3. Put the grape into the microwave with the outside part of the grape facing down and the inside part facing up.

4. Close the door and set the microwave for ten seconds. You may want to dim the lights in the room.

You should see a bluish or yellowish light coming from the middle section of the grape. If you get it right, you can get the rising plasma ball effect like the video shows.

This is plasma!

Be careful not to overcook the grape. It will smoke and stink if you let it overcook. Also, make sure the grape has time to cool before taking it out of the microwave.

Other places you can find plasma include neon signs, fluorescent lights, plasma globes, and small traces of it are found in a flame.

What’s Going On?

Plasma is what happens when you add enough energy (often in the form of raising the temperature) to a gas so that the electrons break free and start zinging around on their own.

Since electrons have a negative charge, having a bunch of free-riding electrons causes the gas to become electrically charged.

This gives some cool properties to the gas, like the ability to conduct electricity and also to glow (give off light).

Anytime you have charged particles (like naked electrons) off on their own, they are referred to by scientists as ions.

The microwave cooks your dinner by shooting “light” beams at the food. These light beams are specially tuned to increase the energy of the water molecules inside your food.

Grapes are made mostly with juice that conducts electricity (think of how salt water conducts electricity). The grape halves are like little cups full of this conductive juice connected by a tiny bridge (the part that you didn’t cut all the way through).

When you hit the ON button on the microwave, the energy being shot at your grape moves the electrolytes across the bridge very quickly, which heats up the bridge until it bursts into flame.

The electrons that are traveling through the flame zip across and mix with the air, and a burst of bright plasma shoots up. If you watch carefully, you will see two flames, not one.

Everything is matter. Well, except for energy, but that’s everything else (and we’ll get to that later).

Everything you can touch and feel is matter. It is made up of solid (kind of) atoms that combine and form in different ways to create light poles, swimming pools, poodles and even the smell coming from your pizza.

Traditionally, there have been three states of matter. State of matter means the way the atoms tend to hang out together. Not to be confused with a state like Utah, Wyoming, or confusion. The three states are solids, liquids and gases. However, leave it up to a science teacher to tell you that that’s not the whole story.

There are two more states of matter. They are plasma and (are you ready for this next one?) the Bose-Einstein condensate. These two states of matter are both pretty uncommon on Earth.

Believe it or not, plasma makes up a very large percentage of the matter in the universe. Are you wondering how come you’ve never heard of it before? (By the way, blood plasma is different from this stuff, and a good thing too!)

Well, there is very little of it on Earth and the plasma that is here is very short lived or stuck in a tube. Plasma is basically ionized gas or in other words it is gas that is electrically charged.

The stuff in florescent light bulbs is plasma. Plasma TV’s have plasma (go figure) inside of them. Lightning and sparks are actually plasma!

Additional Questions and Activities

1. Does it matter where the grape is located inside your microwave?

2. What happens if you put two grapes in?

3. Does grape size matter?

4.  Does the power setting matter?

5. How does a microwave heat your food?