Hands – On Activity #1

Science Area: Matter, Energy, and Machine 3.15 Some things dissolve

in others and some do not.

Materials: * a glass jar or clear drinking glass * salt

* vegetable oil * water

* food coloring (optional) * measuring cup

Sketch:

State Goals: 11.A.1a Describe and observe event.

11.A.2b Collect data for investigations using scientific process skills including

observing, estimating and measuring.

Safety Considerations: Avoid spills. Avoid contact with eyes.

Science Process Skills: make predictions, observe and describe, draw conclusions and interpret results.

Procedures: 1. Pour about 3 inches of water into the glass/jar.

2. Pour about 1/3 of vegetable oil into the glass/jar. When

everything settles, is the oil on top of the water or underneath it?

3. Add 1 drop of food coloring into the glass/jar. What happened? Is

the drop in the oil or in the water? Does the color spread?

4. The salt will sink to the bottom of the mixture, carrying a blob of

oil with it.

5. Add more salt to keep the action going.

6. As the blob dissolves, the salt releases the oil, which floats back

up to the top of the water.

Explanation: Oil floats on water because a drop of oil is less dense than a drop of water.

Density is a measurement of how much given volume of something weighs. Things

that are less dense than water will sink. Oil and water don’t mix well. Salt is heavier than water, so when the salt is poured on the oil, it sinks to the bottom of the mixture, carrying a blob of oil with it. In the water the salt starts to dissolve. As it dissolves the salt releases the oil, which floats back up to the top of the water.

Source: Pat Murphy, Ellen Klages, Linda Shore, and the Exploratorium. The Science Explorer

Out and About. Henry Holt and Company,Inc. New York. 1997. pg 104-105.

Hands – On Activity #2

Science Area: Matter, Energy, and Machine 3.15 Some things dissolve

in others and some do not.

Materials: * 3 clear plastic cups * water

* salt * seltzer water

* food coloring * measuring spoon

Sketch:

plain water salt water seltzer water

State Goals: 11.A.1a Describe and observe event.

11.A.2b Collect data for investigations using scientific process skills including observing, estimating and measuring.

Safety Considerations: Avoid spills. Avoid contact with eyes.

Science Process Skills: make predictions, observe and describe, draw conclusions and interpret results.

Procedures: 1. Fill two cups 2/3 with water.

2. Add 1 drop food coloring to the first cup and immediately observe what happens.

3. Add the salt to the second cup and stir until salt dissolves.

4. Add 1 drop food coloring to the second cup and observe.

5. Fill third cup 1/2 with seltzer water.

6. Add 1 drop food coloring to the third cup and again observe.

Explanation: In salt water, the drop starts to sink and then rises. In plain water the drop slowly swirls and moves throughout. In the fizz water, the drop quickly disperses and evenly colors the liquid. Food coloring is simply colored water. Mixing it in plain water does not have a dramatic effect other than that the color becomes diluted (more pale). Salt water is more dense than plain water. This means that anything less dense will float on the top, including the food coloring (colored water). This is why it is so easy for us to float in the ocean when swimming. The gas bubbles in the fizz water act to speed things up. The drop of food coloring is quickly broken up and is quickly carried to all parts of the liquid.

Sources: http://membership.acs.org/C/Chicago/eled/cheers.html#drops

Hands – On Activity #3

Science Area: Matter, Energy, and Machine 3.15 Some things dissolve in others and some do not.

Sketch:

warm water cold water

Materials: * 2 cups * 2 bouillon cubes

* warm and cold tap water * spoon

State Goals: 11.A.1a Describe and observe event.

11.A.2b Collect data for investigations using scientific process skills including observing, estimating and measuring.

Safety Considerations: Avoid spills. Avoid contact with eyes.

Science Process Skills: make predictions, observe and describe, draw conclusions and interpret results.

Procedures: 1. Fill one cup with cold tap water.

2. Add one bouillon cube.

3. Allow this cup to sit undisturbed while the second cup is prepared.

4. Fill the second cup with warm tap water.

5. Add one bouillon cube to the water and stir.

Explanation: The solid cube dissolved more quickly when placed in warm water and stirred. Dissolving means that the solute breaks apart and moves evenly throughout the solvent. The bouillon cube is the solute and the water the solvent. Heat causes the molecules of water to move faster and the water molecules hit the cube, causing pieces to break off. Stirring increases the breaking process. The cube will finally dissolve in the cols water, but it takes a much longer period of time. Stirring the cold water will help speed up the dissolving.

Source: VanCleave, Janice. 201 Awesome, Magical, Bizarre & Incredible Experiments. John Wiley & Sons, Inc. New York. 1994. pg. 60.

Related Links:

http://membership.acs.org/C/Chicago/ChmShort/cs99.html

http://membership.acs.org/C/Chicago/eled/cheers.html#drops

http://www.exploratorium.edu/science_explorer/volcano.html

http://www.csulb.edu/~lhenriqu/300demo.htm#PaulCoe

http://familyfun.go.com/parenting/learn/activities/feature/famf119weirdsci/famf119weirdsci2.html

http://homeschooling.about.com/od/sciexperiments/p/sciexp408.htm

http://www.onekama.k12.mi.us/onek2k/g5/science.htm

http://nicholasacademy.com/scienceexperiment220sweettea.html

http://www.cruftbox.com/cruft/docs/dissolve.html

http://www.alka-seltzer.com/as/experiment/student_experiment1.htm

http://www.chatham.edu/PTI/Kitchen_Chem/BCleveland_01.htm