http://www.voanews5aitmne6gs2btokcacixclgfl43cv27sirgbauyyjylwpdtqd.onion/a/6998909.html
But you can realize that you can just use, you know, your ordinary house vinegar and you can use some sodium bicarbonate, which is just, you know, soda. And you can just have a little experiment with household items and it's really good for kids to know that, you know, you can do it at home. You don't need to be in a science lab to do it.