Investigating Diffusion of Molecules in Liquid
Summary
Students will investigate how molecules move in liquid. They will use liquids, at different temperatures, to see how food coloring molecules move. Students will begin by forming questions that they have about how long it will take the food coloring to dissolve in different temperatures of liquid. They will plan their investigation and identify the variable they will change in their experiment. They will collect and record data they found in their observations. Students will share their data in small and large groups to compare their findings.
CollapseLearning Goals
This activity is designed for students to do a scientific inquiry. The students will develop skills in designing and implementing a scientific inquiry. They will observe that molecules in liquid move, and in a random manner. Students will learn that heat will increase and cold will decrease the speed of molecular movement in water. Students will use their creativity in modifying a science investigation.
Context for Use
This activity is based on grade 5 standards, although it is used in a multi-age classroom for grades 4-6. The activity is a guided inquiry that is done in the classroom. The anticipated time needed is one 60 minute class period. Special equipment needed includes: clear cups, food coloring, cool water, warm water, ice cubes, eyedroppers/pipettes, isopropyl alcohol, dishwashing soap, markers/colored pencils, and timers.
Students should wear goggles and lab coats if they have them.
Students should wear goggles and lab coats if they have them.
Description and Teaching Materials
The activity begins with the teacher placing food coloring into a room temperature beaker of water. The teacher times how long it takes for the food coloring to dissolve in the water. The students are asked to observe how the food coloring moves in the water and record what they observed in their notebooks. As a class, discuss what was noticed. The teacher records the observations on the board. Next, record what the students know about water, food coloring, and molecules dissolving in liquids. They will then write what they want to know about how food coloring will dissolve in the liquids available. They may have questions such as, will the food coloring move different in hot water or ice water? How will the food coloring move in alcohol? Students will then move to a lab area to complete their experiment. They will record their observations in their science notebooks. Students can use markers/colored pencils to record how the food coloring blended in the liquid. The students can continue to experiment, as time allows, to try other questions they have for the investigation. Students will then journal about what they found in their investigation. They will write what they observed and then share their findings in their small groups. Finally, the large group will come back to share their findings and their explanations.
Teaching Notes and Tips
This activity can be messy with the use of food coloring. Lab coats on the students and newspaper on their work stations can reduce the mess. Students should be encouraged to try as many variables as time allows to ensure that they can start to come up with some possible explanations for how the liquids interacted. They should also be aware of any occurrences that would help them to critique their experiment, such as added variables that could give them inconsistent outcomes.
Assessment
Students will be recording their questions, observations, and analysis in their scientific journals, which will be used for assessment purposes. Classroom observations will also be used as an assessment tool.
Standards
5.1.1.2.1-Generate a scientific question and plan investigation
5.1.1.2.2-Identify and collect relevant evidence
5.1.1.2.3-Conduct or critique an experiment
5.1.1.2.2-Identify and collect relevant evidence
5.1.1.2.3-Conduct or critique an experiment