Speech topic: The Density Column.
Introduction
Laura: Good morning everyone. My name is professor Crazy Fligm Wigms
Sabi: And my name is professor Wodle Ding Aloo.
Laura: Today we are going to do a physical reaction.
Sabi: That's right professor Crazy Fligm Wigms. We will show you what this experiment is called once we show you the ingredients. Professor, bring in the ingredients.
Laura: Okay, to do this experiment you will need the following items: a tall clear jar, container, golden syrup or honey, water, oil and detergent.
Sabi: Now as we promised you, the name of this experiment is "THE DENSITY COLUMN".
Laura: The formula you need to calculate density is: This means you measure the mass per unit volume.
Sabi: If you are wondering what these weird things on the table are, well they are called molecules. This one is one of our ingredients, it is called dihydrogen monoxide (H2O) or water.
What you need?
To do this experiment you need the following items:
- tall glass jar
- container
- golden syrup or honey
- water
- lamp oil
- food colouring
- detergent
Aim
The aim of this experiment is to see the different densities of water, lamp oil and golden syrup.
Hypothesis
Our hypothesis is that once we put in all the ingredients they will stay separated.
Methodology
- Chose a colour from the rainbow food colours. Add the food colouring into the water which is in a container. Stir carefully.
- Carefully pour some golden syrup, water, and oil into the container in that order. What do you see?
- Add a drop of detergent. What happens?
Observation
The golden syrup sunk to the bottom because it is dense. The lamp oil however stayed at the top because it has a smaller density than water and golden syrup. The water stayed in the middle because it has a smaller density than golden syrup but a greater density then lamp oil.
Conclusion
Golden syrup, water and oil have different densities so they don't mix. Instead they form three different layers. The denser fluids sink to the bottom while less dense fluids rise to the top. Where other objects sit in the density column depends on how dense the objects are.
Although water golden syrup and lamp oil have different densities they can still be mixed into each other. Our conclusion is that our hypothesis was correct. It was correct because the ingredients did stay separated.
Safety Notes
Don't swallow the food colouring, the detergent or the lamp oil. To prevent any stains you should have a cloth under the experiment or you can do your experiment outside.
Causes
The cause of the density column is called Intermolecular force. This is what it means: the force between two molecules.
Real life reaction
You use densities in everyday life such as washing the dishes, using body oil and even making things float. The ability to make an object float is called buoyant force.
Laura: I hope you have enjoyed watching our experiment.
Both: Thank you.
Thursday, 16th of April 2009. Melbourne, Australia