Post on 11-Apr-2017
WHAT FLOAT? WHAT SINK?Cam-Tu Diep
FLOATING AND SINKING An object floats when it rests on top of a
liquid or when it rises in the air. Apples float in water. Hot air balloons float in the air.
FLOATING AND SINKING An object sink when it drop down in
liquid or when it falls down through the air. Rocks sink in water. Rock should also sink in air. If the pebbles can’t float in water. They couldn’t float in air either.
WHAT FLOATS? WHAT SINKS? Solid objects are not the only things that float
and sink. Liquids and gases do too.
A bubble is a liquid with gas inside it. Bubbles float.
Corn oil and syrup are both liquids. Corn oil floats in syrup.
Corn Oil
Colored Water
MILK AND CHOCOLATE SYRUP ARE LIQUIDS. BUT ONE IS DENSER THAN THE OTHER
If you’ve ever poured chocolate syrup into milk, then you know that the sauce will sink.
AIRThe air in our environment is
made up of many gases.
The air we breathe here on Earth is made up of different gases. It contains around 78% nitrogen, 21% oxygen, 1% argon and a small amount of other gases.
GAS
Helium balloons float in the air. The helium inside these balloons allow the balloons to float. Gases such as propane and butane do not float in air.
DENSITY All solids, liquids, and gases have
density. Density is how heavy something is
compared to its size.This bowling ball isn’t very big but it is very dense so it is extremely heavy.
DENSITY These candy treats are about the same size.
One is solid chocolate. The other has a lot of air inside. The solid chocolate has more density.
WHAT FLOATS? WHAT SINKS? Object will sink if they have more density
than the liquid or gas they are in.
http://youtu.be/RUMX_b_m3Js
WHAT FLOAT? WHAT SINK?
WHY DO THINGS FLOAT? AN EASY LESSON
http://youtu.be/y0SnFCs9z1g
Have you ever heard the story of Archimedes, an ancient Greek scientist? One day, he noticed the water level rising when he got into his bathtub. He was so excited, he hopped up and ran out into the street stark naked, shouting, "Eureka!" ("I've found it!")
DISCUSSION If something is heavier than another, does this mean that
the heavier item will sink? Not necessarily, because a really heavy boat floats yet a light penny sinks. But a boat has to be careful not to overload itself as it could reach a point where it becomes too heavy and could sink.
Does the shape of an object determine whether an object sinks or floats? Sometimes it does. If you make a tin foil ball that sinks, you can then stretch out the tin foil and make it float. It is the same weight, but the weight is spread out across a larger space (change in density).
The peel on the orange is spongy and full of air pockets, thus allowing the orange to float. Once the peel is removed, the ‘naked’ orange sinks. The orange peel acts like a life jacket which helps humans to float when in water.
EXTRAS The following slides contains extra
information about this topic that you can add to the program if you’re doing a longer program or a program for older kids.
ARCHIMEDES’ PRINCIPLE Archimedes’ principle is better known as the
law of buoyancy (the ability to float in a liquid or to rise in a fluid ).It states: Something submerged(partially or fully) in water experiences a force that tries to push it up (and out of the water). The amount of that force is exactly equal to the WEIGHT of the WATER that the object is displacing.The following video website (video included) provides a great review of Archimedes' Principle
http://youtu.be/eQsmq3Hu9HA http://youtu.be/qvlurmJNDEw
LIQUID DENSITY
This test tube contains corn syrup on the bottom, colored water in the middle, and oil on the top
Liquid Density
Density is mass (how many atoms are in an object) divided by volume.
The more atoms a liquid contains the denser it will be.
REFERENCES What floats? What sinks? : a look at
density / Jennifer Boothroyd. www.science4mykids.com