Flashlights

the sap or rosin came to the surface and dried to spheres that reflect their golden color.

Yes it is possible to make an acid battery using the acid in a lemon. (you would need allot of lemon batteries to light a flashlight bulb though - try using a diode light bulb)

For more information on how to do this look in the link I will place below.

Heat to make the filament glow white hot and emit light (electromagnetic radiation).

80/2 = 40 deg

The light helps the flash light fish attract its food like shrimp krill and small fish hope this helped!

You have + and - on batteries, the polarities have to be in the same direction or the current won't flow.

I can't give you a for-sure answer, but Cree LEDs are some of the most efficient out there.

For a normal battery,for example,AA,AAA,CR123A,CR2 it can just work alittle time and not steady. But for charging batteries,it is steady and can be used fora long time,for a normal 18650 battery,with 70 LM, it can be used for 2-3 hours the LED flashlight is excellent,here is an experience i can share with you: It was a night,when i come bace to my home late,but that day was very special,because it was very dark everything not as usual,then when i went to a shop,i was told our power cut.How worried i was because i can do nothing.Hardly have i reached my house i found it was very bright.My housemate are using her LED flashlight,how happy i was,still i can do everything as usual.She told me she bought from her friend 8 years ago who work in a manufacturer and make LED fllashlith,he said the LED recharging flashlight using special ulria bright white LED,LED light source is the best light source in the world,it is environment protect,long use time (about 3 times)than any other light(incandescente lamp,mecury lamp).and power save,safe and solid performance,realy excellent.And then it was working as the first ,high bright.Sometimes she took it to travel and Camping, climbing, fishing, and other outdoor sports and so on.It just recharge for 4 hours and can charge more than 2 hours.He just need to recharge indoor and then took it is ok. I was so attracted by this LED flashlight, so then i bought one too.Excellent!!!

i'm not very sure, but i know it has magnets. as for zinc, you will have to see if someone else answers it. Yeah...;.

Invented in Germany in 1887, the world's first flashlight consisted of a mixture of magnesium, potassium chlorate and antimony sulphide. when ignited, the "blitzlichpulver" (flashlight powder) burned quickly and brightly, creating a pure white light.

The downside however, was that the dense white smoke released by this reaction was also hazardous to health.

Try the Torch from www.wickedlasers.com -4100 lumens for under 300 dollars

spotlight, torch, electric lamp