Physics: Floating and Sinking with Different Materials
Explore how materials behave in water
Physics: Floating and Sinking with Different Materials
Explore how materials behave in water
Physics - Grade 2-3
- 1
A wooden block and a metal spoon are placed in a tub of water. Which object will most likely float, and which object will most likely sink?
Think about what happens to a stick and a coin in water.
The wooden block will most likely float, and the metal spoon will most likely sink. Wood is usually less dense than water, while metal is usually more dense than water. - 2
Circle the object that is most likely to float: a rubber duck, a glass marble, or a rock. Explain your choice.
The rubber duck is most likely to float because it is light for its size and may have air inside. The glass marble and rock are usually more dense than water and sink. - 3
Mia drops a plastic bottle with the cap on into water. It floats. Then she fills the bottle with water and drops it in again. What will probably happen, and why?
Air inside an object can help it float.
The filled bottle will probably sink or float lower in the water. Adding water makes the bottle heavier and leaves less air inside to help it float. - 4
A small ball of clay sinks when placed in water. If the same clay is shaped like a little boat, it may float. Explain why changing the shape can help it float.
Think about how a heavy metal ship can still float.
Changing the clay into a boat shape can help it float because the shape spreads the clay out and traps air. The boat shape pushes more water out of the way, which can help hold it up. - 5
Look at this list: cork, penny, sponge, steel nail. Sort the objects into two groups: likely to float and likely to sink.
The cork and sponge are likely to float. The penny and steel nail are likely to sink because metals are usually more dense than water. - 6
A sponge floats at first. After it soaks up a lot of water, it sinks lower in the water. Why does this happen?
Dry objects with air pockets often float better than wet ones.
The sponge sinks lower because it becomes heavier when it soaks up water. The water fills spaces that used to hold air. - 7
Two objects are the same size. One is made of foam, and one is made of metal. Which one is more likely to float? Explain your answer.
The foam object is more likely to float because foam is light for its size and often contains tiny air spaces. The metal object is more likely to sink because metal is heavy for its size. - 8
A student says, "All big things sink and all small things float." Is this always true? Use an example in your answer.
Size alone does not decide if something floats or sinks.
This is not always true. A large boat can float, while a small pebble can sink. Floating and sinking depend on the material, shape, and how heavy the object is for its size. - 9
In a science test, a leaf, a paper clip, and a crayon are placed in water. The leaf floats, the paper clip sinks, and the crayon floats. Write one observation from the test.
One observation is that the leaf floated in the water. Another correct observation is that the paper clip sank or that the crayon floated. - 10
You want to test whether a new classroom object floats or sinks. Write the steps you would follow to do a fair test.
A fair test changes only one thing at a time.
I would fill a container with water, gently place the object in the water, and watch if it floats or sinks. I would use the same container and water level for each object so the test is fair.