Water – Objects That Float Basic 2 Basic Science Lesson Note

Learning Objectives: By the end of this lesson, pupils should be able to:

• mention objects that float in water
• describe the characteristics of objects that float in water
• demonstrate how to make objects float in water

Lesson Content:

What is Floating in Water? Floating is when objects stay on top of water instead of sinking to the bottom. Objects float because they are lighter than the water they push aside.

Objects That Float in Water:

Natural Objects:

• Wood: Most pieces of wood float

Leaves: Tree leaves float on water surface

• Feathers: Bird feathers are very light

• Ice: Frozen water floats on liquid water
• Oil: Cooking oil floats on water
• Cork: Natural cork from trees

Man-Made Objects:

• Plastic bottles: Empty bottles with air inside
• Boats: Ships and boats designed to float
• Rubber balls: Air inside makes them float
• Life jackets: Designed to help people float
• Styrofoam: Very light plastic material
• Empty cans: With air inside, they float

Everyday Floating Objects:

• Soap: Bar of soap floats in bath
• Balloons: Air-filled balloons float on water
• Plastic cups: When empty or with little water
• Paper boats: If made waterproof
• Coconut shells: Empty coconut shells

Characteristics of Objects That Float:

1. Density (Lightness):

• Less dense than water: Objects lighter than same amount of water
• Air inside: Objects with air spaces float better
• Light materials: Wood, plastic, cork are naturally light

2. Shape Matters:

• Hollow shape: Bowls and cups can float if right-side up
• Wide and flat: Large surface area spreads weight
• Boat shape: Designed to push water aside and stay up

3. Material Type:

• Natural floaters: Wood, cork, oil
• Synthetic floaters: Most plastics, styrofoam
• Trapped air: Objects with air pockets inside

4. Water Displacement:

• Push water aside: Floating objects push away water
• Buoyant force: Water pushes back up on object
• Balance: Object floats when forces balance

Demonstrating How to Make Objects Float:

Experiment 1: Making Clay Float Materials: Clay, water container Steps:

1. Roll clay into ball – it sinks
2. Shape clay like a bowl – it floats!
3. Explanation: Bowl shape traps air and spreads weight

Experiment 2: Floating Different Materials Materials: Various objects, large water container Test objects: Cork, stone, wood block, plastic bottle, metal spoon Procedure:

1. Predict: Guess which will float
2. Test: Place each object gently in water
3. Observe: Which float, which sink?
4. Record: Make list of floaters and sinkers

Experiment 3: Making Foil Float Materials: Aluminum foil, water Steps:

1. Crumple foil into tight ball – it sinks
2. Shape same foil into boat shape – it floats!
3. Explanation: Shape changes how foil sits on water

Experiment 4: Adding Weight to Floaters Materials: Floating object (cork), small weights (coins) Steps:

1. Start with cork floating in water
2. Add one coin at a time on top
3. Watch what happens as weight increases
4. Eventually sinks when too heavy

Making Objects Float Better:

Design Principles:

• Make it hollow: Create air spaces inside
• Spread the weight: Make wide, flat shapes
• Use light materials: Choose wood over metal
• Waterproof it: Keep water from getting inside

Boat Building Activity: Materials: Various materials (foil, plastic containers, cork, clay) Challenge: Make a boat that can carry the most weight Steps:

1. Design your boat shape
2. Build using materials provided
3. Test in water – does it float?
4. Add weight (coins or small objects) to test capacity
5. Improve design based on results

Real-World Applications:

Transportation:

• Ships: Designed with hollow hulls to displace water
• Boats: Various sizes, all use floating principles
• Submarines: Control floating by adding/removing water

Safety:

• Life preservers: Help people float in emergencies
• Life boats: Emergency floating vessels
• Pool floats: Help people who can’t swim

Industry:

• Oil cleanup: Oil floats, can be removed from water surface
• Lumber transport: Logs floated down rivers
• Fishing: Fishing nets use floats to stay at surface