Density

A L i t t l e B i t A b o u t D e n s i t y ! By: Yasmine and Braelie

Table of Contents 1. Density 2. What is Density 3. Comparing Densities and Substances 4. Charging Densities 5.Work Cited

Density To find out why an object floats or sinks you must compare the object’s mass to its volume. That is also called finding the density. ** What is Density? ** “The density of a substance is its mass per unit volume”(Jones). Equation: Density=Mass / Volume The density of an object is always measured in cubic centimeters per the measurement of grams. For example the measurement of an object that is 11.3 grams the density would equal 11.3 grams per cubic centimeters. Water is always measured as a density of 1.0 grams per cubic centimeter. So therefore anything with a density above the density of water is more dense than water and things with less density is less dense than water.

 <-- **This piece of cork's density is less than that of the water therefore allowing it to float on the surface of the cup of water.**

** Comparing Densities and Substance s ** Some liquids can float on top of other liquids. If you were to put two different objects (or liquids) in a cup, then the ones that have the most density will be on the bottom while the objects with the least amount of density will float on the top of the others. If the density of the object is equal to that of the liquid then the object will float at a constant depth.In other words this means that if you put an object less dense than water in a glass of water it will float and if it is more dense than the water it will sink, therefore if it is the same measurment of density as the water then it will stay in one spot or float at a constant depth in the water.

 This is an example of something that equal to water, notice how it doesn't sink or float. "It remains at a constant depth" (Jones)

** Changing Density ** By changing the density you can figure out why an object floats or sinks. For example the density of water can change by freezing it to ice and the ice can float in the water, therefore the ice is less dense than the water even though they are both the same substance. Water expands when it is frozen, thus making the ice take up more space. (Did you know? Ice burgs are really big ice-cubes!)By changing an object’s density you can either make it sink or make it float. Volume stays the same while the density depends on the mass’ increase. Thus creating the object that you are measuring to dive farther down into the water. This is also explained as a buoyant force. Changing water level can change the object’s density. The object will dive when its weight is bigger than the buoyant force. It will rise to the surface when the object’s weight is less than the buoyant force. (Don’t forget: air is also a fluid!) If you decrease the density in a balloon then the balloon will float and not sink in the air. Instead of regular air you can also fill a balloon with a gas called helium. A balloon that is filled with helium,(like the ones at your birthday party ) will float in air because helium is less dense than air. However, a balloon filled with air will not float in air because its denser then the surrounding air. This is because the air inside the balloon is under pressure. This results in the balloon falling to the ground.

This is ﻿ an example of ice floating in water. Notice how the ice is floating in the water, making it less dense. Even though they are the same substance. media type="custom" key="7992414" align="center"

media type="custom" key="8022298" Work Cited: Jones, "Motion, Forse and Energy." Ed. Upper Saddle River: Pearson Education, Inc., 2009. Print <span style="color: #333333; display: block; font-family: times new roman,times,serif; font-size: 12px; font-style: normal; letter-spacing: 2px; margin-left: 20px; padding-bottom: 20px; padding-left: 20px; padding-right: 20px; padding-top: 20px; text-align: left; text-indent: -20px; width: 350px; word-wrap: break-word;">"Density." //Xtranormal//. Web. 11 Jan 2011. "Glog-74." //Xtranormal//. Web. Jan 2011. .