At the first-grade level, students should be able to use thermometers to make temperature readings, and this is a good objective for your lesson plan. A three-part lesson objective might include teaching students how to use thermometers to measure temperature, instructing them on how to record temperature measurements and associating temperature measurements with specific seasons. This type of teaching objective involves a practical action, as well as applications of that action.
Some teachers prefer to use actual thermometers to take temperature readings of hot and cold water, for example, or outdoor air temperature. As an alternative, you can just prepare a demonstration thermometer using cardboard and markers, with a sliding temperature indicator so you can adjust temperature levels. You may also create seasonal worksheets for each student, so they can associate temperature readings with different seasons. Be colorful and creative to heighten student engagement.
Your lesson plan should emphasize the concept of degrees. Use an actual thermometer or one you've made yourself to teach different degree readings, ask students to determine whether a given reading is relatively cold, cool, moderate, warm or hot and apply these readings to the various seasons of the year by asking the season in which a given reading would be most likely to occur.
Evaluation should focus on how accurately students are able to read temperatures, understand the concept of degrees and link specific temperature readings with the various seasons of the year. If you choose to have the students work in groups, you can also observe the group dynamics to determine how well each student works with the other students in the group.