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Summary:
Students will learn that warm air is less dense than cold air. Students will also learn that objects that are less dense than water will float in the water.
Main Curriculum Tie:
Science - 4th Grade
Standard 2 Objective 1
Observe, measure, and record the basic elements of weather. Career Connections: Materials:
Glass Jars
Spoons
Table Salt
Kosher Salt
Borax (optional)
Epsom Salt
Food coloring
Eggs (hardboiled)
Ice or snow
Water
Electric Kettle
Pencils
Straws or pipettes
Food coloring
Background For Teachers:
Density is a key concept in the understanding of weather and the way the air and atmosphere behaves.
Warm rises and cold air sinks, this is the concept that creates thunderstorms.
Density is a unit mass for a unit volume meaning the density is the amount of mass occupying a space
If an object in water is less dense than water it will float (such as a stick in water).
Student Prior Knowledge:
Students should be able to not make a mess and clean up responsibly. Intended Learning Outcomes:
Students will learn the concept of density as it relates to water and air. Instructional Procedures:
Density of Air:
Lead the students in a discussion of, "Does air has weight?" See if they'd like to make a hypothesis what could impact the weight. Could the temperature change the weight of the air?
PART 1
- Have student form a hypothesis about air density and if hot air or cold air is of different density.
- Give students a jar with hot water filled about halfway and have them color the water yellow.
- Have students color some ice cold water a color such as blue in a small plastic cup. They could also collect snow to make the water cold.
- Students should use the straw (or pipette) to collect some very cold water and slowly lower the straw into the side of the jar. Releasing the water from the straw into the side of the jar they should see where the blue water goes (it should be on the very bottom).
- Repeat the experiment but using cold water in the jar and hot water in the small cup.
Density of Water and Objects:
PART 2
- Have students each get a jar full of cold water and one egg.
- Students should experiment with their egg to check if it floats or sinks in the water.
- After seeing that the egg sinks, have students see what's available to change their predicament. Their goal is to float the egg.
- Students can use ingredients such as sugar, salt, kosher salt, baking soda, or anything else you have lying around!
- Students can also change the temperature of the water.
- Students should WRITE a hypothesis and outline their experiment. They should list what ingredient they will use and why. The hypothesis should be why they think an ingredient will work.
- Students will stir their experimental ingredient into their water (removing the egg of course and replacing it later).
- Have students present their findings to the class.
Strategies For Diverse Learners:
Students can draw what happened and label it in any language.
Extensions:
Students can experiment with other objects with their egg/density solution such as sticks or rocks.
Students can use different temperatures of water to experiment with density.
Author:
Dina Freedman
Irene Rizza
Erin Moulding
Holly Godsey
Steven Pinta
Stanley Smith
Edwin Opperman
Andrew Basinski
Created Date :
Jan 02 2011 21:31 PM
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