Reply To: Trouble with Brownian Motion demo
Sorry not to get back to you until now. From what you describe, I think the problem is in the way you are using your microscope. Use the condenser to cut the light way down so that the background is only a light gray. Then carefully focus. Be sure you are focusing on the liquid under the coverglass. Get a rough focus with 40x, then go to 100x. Hopefully, this will give you something similar to what you see in videos.
I am very happy to see that you are (attempting) giving your kid(s) a first hand experience of this. Please let us know how it goes from here.