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Monday, May 18, 2015

Floating and sinking

Which objects can float? Which sink?
Why are floating objects so useful? (arm bands, safety jackets, life buoys, buoys in the sea, boats)
Why do we need to use some objects that sink? (anchors)
Today we had some investigative time finding out what objects around us float and what sink.
First of all we guessed.
Which of these objects do you think will float and which will sink....................?
a bottle full of water, a boat, a lollipop, a pencil, a sponge, an apple, a spoon, a shell, a key, a stone, a plastic duck, a straw, a wooden block, a metal block, toy animals.
We all guessed (yes, even teacher) and we all got some guesses right and some wrong, (which is ok because a guess is just a guess and doesn't have to be right!)
One thing we noticed is that when an object sinks to the bottom it looks like there are two of it in the water.  Teacher explained that this is due to refraction of light - light bends when it goes through water so we see one object from the top and one from the side of the container.  This gives the illusion of there being two identical objects in the container.
Some of us find this a bit hard so we are just interested to see it in action even if this science is something we will learn more about when we are bigger.
For now we are really enjoying guessing and testing lots of objects to see whether they float or sink.
We can even guess why?  (hint, objects with air in them float and objects that have no air in them at all usually sink).
But what about apples and sponges?
These were a bit of a surprise.
Try floating them and see what we learned!

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