I am trying to work out wjat type of technology I would need to send a signal (warning) that a specific item is in range of an item say 5 meters. Like a transmitter and receiver type devise. Any ideas?

1) video capture. If the picture changes, alert the device.
2) infrared. send out a pulse of infrared light. wait for it’s reflection. Measure the time delay and divide by 2 to get distance.
3) proximity (capacitive). As the dielectric changes due to foreign objects between / near two plates, the capacitance changes.
4) ultrasonic. just like infrared, but uses sound too high to hear.
5) RF. radiate a radio signal. Watch for its reflection from metal objects.

How do they find hidden microphone or other devices and how does it work technologicaly speaking and how do they applied the method of searches in order to get results.

Is it like a radar type deal thing? I can't hardly imagine that it is a very advance technology. In fact I'm pretty sure it is somewhat simple and cheap.
How is it called?
How such device is called?

All electronic devices generate electromagnetic signal. Other electronic devices like sensor can monitor/sweep electromagnetic signal. This devices are simple and cheap, but for make devices with high performance need other electronic circuits and cost.

http://www.searchoptima.com/electronic_sensor.electronics

I'm doing a science project. What are some examples of technology we use often that can be powered by the sun?

- Photovoltaics, which provides electricity to anything that needs it.
- Solar Water Heaters, which provide hot water for a home and are very cost-effective.
- Cars! About 20 universities participate in the American Solar Challenge to build and race cars powered only by solar energy.
- Cooking, particularly in the developing world.
- Photosynthesis, which is pretty important to everything.

This is how it goes in my school:
6th grade- Science in general
7th grade- Life Science
8th grade- Earth Science
9th grade- Physical Science
10th grade- Biology
11th grade- Chemistry
12th grade- None

Also, 9th grade takes Health.
I don't know if that counts as a Science class.

6th-Earth Science
7th-Life Science
8th-Physical Science
9th-Chemistry
10th-Biology
11&12 are varying

I want to not focus on the information age, such as computers and internet, but instead focus on things such as robots, and physical technology.

An example I have so far are roller coasters, without technology they would not be safe and not run.

Anyone have any other ideas?

artificial limbs
pace makers
new medication
incubators
neonatal intensive care units
car seats

Hi Do your know currently the lower secondary science textbook(express/Normal academy) used in most secondary schools? I saw a number of them1) In science 2)Interactive science for inquiring minds 3) new science discovery 4) science matters Which one will it be? thanks!

holt spectrum