Lesson Plans
Three of the following activities are based on a NASA Educator Resource Guide titled "Astrobiology in your classroom Life on Earth . . And elsewhere?" The Resource Guide contains 5 classroom activities for grades 5-10 and can be downloaded in PDF form from NASA. I will use Activity One, What is life?, Activity Two, What does life need to live?, and Activity Three, What makes a world habitable? Two hands-on activities Radiation Measurements and Effect of Distance on Intensity of Light will help students understand concepts needed for the last activity to determine what makes a planet habitable. NASA Activities Four and Five could be used as enrichment activities.
What is life?
Objective
To develop a working definition of life.
Materials
For each pair of students: a copy of Activity Guide for Activity One, a different pair of objects (i.e. live ant and plastic ant) for each pair of students, hand lens. For each group of four students: three jars, hot tap water in a container, 3 tbsp. sand per jar, 1 tsp. sugar per jar, half of ¼ oz. packet dry yeast for jar 2, 1 fizzing antacid tablet, crushed for jar 3, a copy of Think About It for Activity One.
Description
Students compare living and nonliving examples and develop their own working definition of life. The teacher background information lists characteristics that most living creatures share. The procedure suggests having one pair of objects for each student and lists 8 sets of suggested objects. For my classroom, I will need to have students work in pairs and will also need to increase the number of objects from 8 to 14 for classes up to 28 students. After the pairs of students have recorded their observations on the Activity Guide that is included in the Educator Resource Guide, students form groups of 4 students, compare the two lists, and create a new list with a common set of characteristics to use to identify life.
Students next test their definitions by playing a modified game of "20 Questions". I will first model the game with the class helping students form yes/no questions. The number of questions will be reduced to between 5 and 10. The Educator Resource Guide suggests some objects to use when modeling the game that should really help students to refine their original lists. Each group of 4 students will then think of an object for the rest of the class to question and subsequently guess the identity. These activities will take one class period.
The next class period each group of 4 students will observe, using a hand lens, three jars (sand and sugar; sand, sugar, and yeast; sand, sugar, and an antacid tablet). They can smell, touch, and listen but not taste. Students will then add hot water and make and record new observations. Each group will report to the class their findings and record their information on a class chart. The class will create a new working definition of life and students will complete the questions on the Activity Guide. The teachers' guide also includes a sheet of "Think About It" questions for use as a reflection on the activity. The suggestion is to use this sheet as an evaluation tool or for homework. I will use it for in class assessment and allow students to work together.
What does life need to live?
Objective
To establish the fact that all life requires water, nutrients, and energy to live.
Materials
For each group of students: a copy of Activity Guide (p. 16 & 17) for Activity Two, a copy of How to tell what's growing in your environment (p. 19) for Activity Two, a different Environment Card (p. 15), material for each of the twelve environments (see p. 14), hand lens and/or microscope.
Description
This activity will probably take two class periods for the set up and to complete the Activity Guide questions and another full day at the end of the activity to complete the Think About It questions. Since there are 12 environment cards and set ups, students groups will consist of 2 to 3 students depending on the number of students in each class. Student groups will think about, discuss with each other, and then create a list of what is needed for an organism to live a long time. Then each group will select at random one of the 12 environment cards. Students will then write a set of instructions (5 to 10 steps) to maintain this environment for 10 days in order for the organism to live. After getting approval of their plan from the teacher, students will prepare the environment following their plan. During the observation time, students will record their observations each day when they first come into the classroom. Students will include a drawing with their daily observations. The guide sheet will help students identify what is growing. At the end of the activity, students will answer the Think About It questions. During the ten-day observation period, students will complete activities on What makes a world habitable?
Radiation Measurements
Objective
To measure and compare the energy reflected and absorbed by different colored objects.
Materials
Per group: Styrofoam cup, 2 thermometers, data table, mirror, and ruler
Steps
- Construct a simple radiant energy collector by making a hole in the center of the bottom of the cup using a pencil that is about the same diameter as the thermometer. Push the thermometer through the hole so that the bulb part is inside the cup 1 to 2 inches.
- Take the students outside on a sunny day and have them measure temperature for a number of objects of different colors, including at least one dark and one light object. For each object, the students should measure both the temperature at the surface using the plain thermometer and above the object using the thermometer in the cup.
- Students should also measure the temperature above the mirror and directly on the mirror.
- Students should be sure to hold the radiant energy collector the same distance above all objects.
- All measurements should be recorded in a data table.
- Students will analyze data and based on their temperature data determine which colors absorb more energy and which reflect more energy.
Effect of Distance on Intensity of Light
Objective
To illustrate how The Inverse Square Law applies to intensity of light as distance changes. As the energy from a point light source radiates out, its intensity diminishes rapidly. Students will use the inverse square law to understand this relationship.
Materials
3 sheets graph paper, a ruler, and 1 flashlight per group
Steps
- 1. Label one sheet of graph paper Earth, one as Mercury, and one as Mars.
- 2. One student holds the flashlight 6 inches above the graph paper labeled Mercury.
- 3. The other student draws a circle around the brightest circle on light on the paper.
- 4. Students repeat the same procedure using 12 inches for Earth and 24 inches for Mars.
- 5. Students then count the number of squares enclosed by the circles. Students will have to estimate ½ or ¼ of a square for those partially enclosed squares depending on the size of the square on the graph paper. As an alternative, students can count all squares that have some light shining on them based on the assumption that these partially lit squares will average out.
- 6. Students will then calculate the energy per square. As all three graphs have the same intensity of light shining on them from the same flashlight, an assigned number for this energy can be used. The amount of power can be calculated by multiplying current times voltage. The flashlight bulb should indicate current in amperes (amps) and voltage in volts (v). Example is 0.7 amps. X 2.4 v = 1.7 watts. If you use two new 1.5 volts batteries in series the voltage should be 3.0 volts, so you could use either number for voltage.
Math Extension
The NASA Educator Research Guide Activity 3 Math Extension describes a class demonstration activity using an overhead projector that should help students understand the results from their experiment. Even though the projector is not a point source it still demonstrates the inverse square law fairly well. The intensity of the light energy changes in a predictable way as the light spreads out. At too great a distance from the Sun, the amount of energy is so reduced that the planet does not receive enough energy. The teacher shines the projector on a blackboard or whiteboard, students trace the lighted area on the board, measure the length of one side of the lighted square, and measure the distance from the light source to the board. The length of one side is squared to get the area of the lighted square. Students record their data in a data table. The distance of the projector to the board is subsequently doubled and then tripled. Students will make predictions first, collect new data, and record. Students will graph their data to see the trend and make further predictions based on their graph.
What makes a world habitable?
Objective
To assess the possibility of life in the Solar System.
Materials
For each group of four students: One set of Habitability Cards, A Key of habitability factors (p. 35) reference sheet, and Searching for a habitable world (p. 36) data chart.
Description
With background from the computer activities and the hands-on activities previously described, students should be prepared to compare other planets to Earth to determine if they could support life. Students will use Habitability Cards with facts about each of the planets and some of the moons of our Solar System along with A Key of habitability factors reference sheet to assess whether each planet or moon is a possible candidate for life or not. This activity uses the key habitability factors of temperature, water, atmosphere, energy, and nutrients. On the data chart, students will checkmark whether life is likely, life is possible, or if life is unlikely and state their rationale for their choice. After each group has completed the chart, the group will select its top 3 candidates and record their choices on a class chart and explain their reasoning to the whole class.
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