Modulate the light output of the LED with the output from a microphone. Align the beam of the LED with the photo diode set up across the room. Amplify the signal from the photo diode and feed to a loud speaker. If one speaks into the mike the voice will come through the speaker without any radio waves being used.

This can be useful for defense where radio silent communication is needed.

We took 2 large containers (bowls/buckets) and filled one with red colored water to represent blood. The we got a siphon (used to fill a kerosene heater). She used the siphon to move the “blood” from one container to the next. The part you squeeze with your hand represents the heart and the 2 tubes represent the veins and arteries. This flows very easily.

Your report will show that smoking one cigarette reduces the size of the arteries by 30%. Buy 2 slightly smaller tubes that will fit into the tubes (arteries) on the siphon. Then pump it again. It will be a lot of work without much “blood” going thru.

This shows how the heart enlarges (because it is a muscle and is working too hard) and it shows how the blood doesn’t flow well to all body parts (like feet and hands) which will deprive the body of oxygen. (because that’s the blood’s job is to deliver oxygen)

It’s very simple and very cheap. My daughter did this because she wanted to know why her Papa’s feet were purple from smoking. He died a short time later. She was asked to show this project to several classrooms of middle school children so they would truly understand some of the effects.