National Engineers Month

	Activities by Grade	K - 2		5 - 8
		3 - 4		9 - 12

Condiment Diver

This idea has been copied from the book "While You're Waiting For the Food To Come" by Eric Muller.

Ingredients:

• one condiment packet (ketchup, or soy sauce, or hot sauce)
• one clear plastic bottle with lid (empty soda liter works great)
• one glass of water

Prep
As always, read through the entire activity and practice it at home at least once to make sure your device works.

Fill the empty plastic bottle up to the tippy-top with water. The more full it is, the better this will work. Put the condiment packet inside the bottle. Screw on the lid. "The device you just made is called a Cartesian diver.  There are huge Cartesian divers that travel around the world underwater. They are called submarines! Both your device and submarienes go up and down by squeezing the air in the chamber at the top of the packet. A submarine goes down because water is pumped into an air-filled chamber. In both devices, large and small, a change in density or the way they are packed with "stuff" makes them sink or float.

Activity

Keep the device hidden until you're ready. Or the kids' curiosity will be too distracting from your introduction. When you're ready, take out your device. Tell the kids that you can move the packet inside the bottle just by thinking really really hard.  Hold the device up where they can see it and close your eyes like you're meditating, saying "down, down, down."  As you're saying this, gently squeeze the middle of the plastic bottle. Your packet will begin to sink.  Then 'meditate' it back to the top by letting go of the bottle.  Tell them they can do anything they put their minds to, if they really try. Ask th teacher to demonstrate his/her 'meditating' techniques.  Ask one of the kids if they would like to come up to the front and try. 

Then ask the class if they think you were really serious. Do they think engineers know magic? Of course not. There must be a reason. Engineers are always asking questions about how things work, how things can work better.  What is making the packet move? As kids throw out ideas, see if they work.  After a couple guesses, start explaining it.  "The air bubble at the top of the sauce packet determines whether the packet will sink or swim. Squeezing the bottle causes the bubble to shrink. This smaller bubble can't keep the packet afloat, so it sinks. Releasing the bottle makes the bubble expand, which allows the packet to rise.  Tie in the description of the submarine from the prep work.

For an extended activity, bring different types of condiments and experiment which ones "sink" better than the others. This can be tied into the scientific method. If you have enough supplies, you can bring them with you and offer to let the kids make one of their own to try at home.  Pair them up or put them in groups for this activity.