Hi, young learners! Welcome back to Primary 2 Basic Science Technology. In our previous lesson, we learned about the properties of water. Today, we’re going to learn about Water (Floatation).
Objectives
By the end of this lesson, you should be able to:
- Identify items that float on water.
- Identify items that sink in water.
- Explain why some items float and others sink.
Water (Floatation)
Floatation is the ability of an object to stay on the surface of water without sinking. This happens because the object is lighter than the water it displaces.
What is Density?
Density is how much mass is packed into a certain amount of space. Think of it like this: a big, fluffy pillow takes up a lot of space but doesn’t weigh much, so it has low density. A tiny, heavy rock takes up little space but weighs a lot, so it has high density.
How Density Affects Floatation
When you put an object in water, it pushes some of the water aside. If the object is less dense than the water it pushes aside, it will float. If the object is denser than the water it pushes aside, it will sink.
Examples of Things That Float on Water
Some examples of things that float on water include:
- Wood: Wood is less dense than water, so it floats.
- A leaf: A leaf is light and has a large surface area, allowing it to float.
- A plastic ball: Plastic is generally less dense than water.
- A paper boat: Paper is light and can be shaped to displace water effectively.
- An apple: An apple has a lower density than water, making it float.
Examples of Things That Sink in Water
Some examples of things that sink in water include:
- A stone: Rocks are dense and heavier than water.
- A metal spoon: Metals are generally denser than water.
- A coin: Coins are made of dense materials like copper or silver.
- A ceramic bowl: Ceramic is denser than water.
- A glass marble: Glass is denser than water.
Evaluation Questions
Now that you’ve learned about floatation, let’s see if you can answer these questions:
- Can you name three items that float on water?
- What happens to a stone when you put it in water? Why?
- Explain why a plastic ball floats but a metal spoon sinks.
- Can you think of any other objects that float or sink?
- If you had a piece of wood and a piece of metal of the same size, which one would you expect to float? Why?
Conclusion
Today, we learned about floatation and how density plays a role in whether an object floats or sinks. Remember, if an object is less dense than water, it will float. If it’s denser than water, it will sink. Keep exploring and experimenting with different objects to see what happens! See you in the next lesson!
