水果电池，柠檬真的能发电？

Lemons contain weak acid. 柠檬里有弱酸。 Put two metal strips into the lemon. 把两片金属插进柠檬里。 The acid reacts with the metals. 酸和金属发生反应。 Tiny electric current starts to flow. 微弱的电流就开始流动了。 It can light up a small LED. 它能点亮一颗小小的LED灯。 You can also use potatoes or apples. 用土豆或苹果也能发电。 It is not much power, but it works. 电量不大，但真的能用。