ECSI 317 - Hira and Shannon

1. ECSI 317 POEShannon and Hira

4. Predict
Why does the oil float on the water?
Does this have anything to do with why the
food colouring mixes with the water?
What does the Alka Seltzer tablet change?

5. Predict
Prediction: The oil floats on water because it is
less dense than water. No it does not have
anything to do with the food coloring. The tablet
creates some sort of gas which causes the oil to
move around.

6. Video: Lava Lamps

7. Curriculum Connections
Grade 5 - Physical Properties of Materials in
Solid, liquid, and gases
Grade 7 - Investigate Properties of a Solution
Grade 8 - Density

8. Observe
1. Fill your bottle about 1/4 full with water.
2. Slowly fill the remainder of the bottle with oil until it is
almost full. Wait for the oil and water to separate
3. Add food colouring in the bottle
4. Break an Alka Seltzer tablet in half and drop half into
the bottle.
Watch the lava lamp action commence.

9. Observe: Questions to Consider
Do you think the effect
would be the same if the cap
was placed on the bottle?
Would the temperature of
the water affect the
reaction?
Does the size of the tablet
affect the amount of blobs
produced.

10. Observe
The oil does stay on top of the
water when first added to water.
The food colouring just stays on
top of the oil initially.
The tablet causes bubbles in the
bottle, the colors begin to move
around and a lot of the color
sinks to the bottom.

11. Explain
Oil is less dense than water so stays on top of
the water.
The water molecules are attracted to other water
molecules and the oil molecules are attracted to
other water molecules. The oil and water do not
mix because of intermolecular polarity.
When you add the tablet, it dissolves and creates
a gas. As the gas bubbles rise up, they take
some of the coloured water with them. When the
blob of water reaches the top, the gas escaped
and down goes the water.