Motor Oil: This oil didnt work, it was way too dense so tiny bubbles came up and we had to use 3 complete tablets.
Vegetable Oil: This was the original oil that we were suposed to use and it made the bubbles a bit larger than the canola oil's.
Canola Oil: The oil was really smooth and less dense so the bubbles went by faster but they were big and lasted a long time.
We saw that the oil and the water mixed when we poured the oil in the bottle, but it settled quickly. the three drops of food coloring stayed between the water and the oil. When we dropped the tablet in and it started bubbling, the coloring and the water mixed and the bubbles went up. It looked like it was a lava lamp.