I found this really easy experiment from E is for Explore! You only need a glass, milk, and a can of red bull.
Next, the young scientist poured the Red Bull into the glass of milk.
After, she poured the Red Bull in, we could actually see the milk and Red Bull move and separate in the glass. You can see it swirl a little in the following two photos.
We also noticed that the solid grew. We snapped this photo right after we poured in the Red Bull.
And this is a photo 5 minutes later. Notice how the solid grew a 1/4". When we touched it, it also had a spongy consistency.
We used organic 2% milk. Take a look at the E is for Explore! website to see the video with 5 different milks from E is for Explore! I think that we had a larger percentage of solid than the milks in the video. The teacher recommended whole milk.