In this activity, students will become more familiar with using the metric system to convert units of measurement. Students then will then be challenged to redesign a school cafeteria tray using their understanding of metric system and unit conversion.
This activity will help prepare your students to meet the performance expectations in the following standards:
- MS-ETS1-2: Evaluate competing design solutions using a systematic process to determine how well they meet the criteria and constraints of the problem.
- Scientific and Engineering Practices:
- Asking Questions and Defining Problems
- Using Mathematics and Computational Thinking
- Developing and Using Models
By the end of this activity, students should be able to
- Convert between base metric units.
- Complete measurements using metric units.
This activity supports students’ understanding of
- Metric Units
- Unit Conversion
Teacher Preparation: 30 minutes
Lesson: ~2 hours
- 1 masking tape roll per class
- 7 suction cups per group
- 1 handout per student
- 1 piece of graph paper per student
- Start the activity by asking the students “Where do they use metric or have heard metric being used?”
- Explain to students that in science we use the metric system as a way to communicate our results to each other. Ask students “Why would all scientists agree to use one measuring system to communicate?” This question is on the student handout—ask students to record their response.
- Show the video, Metric System for Kids: Explained through Song and instruct students to complete the rest of the Background questions on the student handout. Also direct students to record the decimal value of each of the metric units shown in the video on the metric line on their student handout. (We will cover these units: kilo-, hecto-, deci-, deci-, centi-, milli-)
- Teachers can demonstrate how to convert units using dimensional analysis, or through a visual method of “moving the decimal place”.
- As a visual aide for moving the decimal place, you can use suction cups to help students visualize the decimal “moving”.
- Students should label the suction cups with the units.
- Students tie a loop on one end of the string. The loop is the starting unit. Then, students wrap the string around the hooks on each suction cup sequentially until they reach the desired unit. This represents “moving” the decimal point (converting the unit), and allows them to physically count the moves each time.
- Have students practice converting measurements by completing the Analysis section in pairs or small groups.
- A Challenge Question has been included for students to apply their understanding to a real-world scenario.
- The Extension section has two parts. Students are tasked with designing and improving a new cafeteria tray. It may help to borrow a current tray from the cafeteria as an example, and to encourage students to think about how they can improve its design and function. Students will create a scaled drawing of the tray on a piece of paper. The scale will vary by student. For example, a student might have a scale that is 1 cm = 2.54 inches, while another may use larger or smaller values.
- The second portion of the Extension section is designated as optional. Teachers may need to determine if enough class time and supplies are available. If students complete this section, they can build the model of their trays using construction paper and glue/tape. Other materials that are available can be used as well.
- An Answer Key document has been provided for this activity.
For the Student
- Why would all scientists agree to use one measuring system to communicate?
- What are the base units?
- How are the base units organized?
- 7 suction cups (per group)
- 1 piece of graph paper
- Write the decimal value and the prefixes for the metric system on each line below.
- Label the arrow pointing to the left increasing.
- Label the arrow pointing to the right decreasing.
Convert the following metric units, and show your work:
- Susy ran 3.45 kilometers but her coach requires her to record her distances in meters. How many meters did Susy run?
- During lab today, Jimmy accidently recorded a volume measurement as milliliters instead of liters. How many liters is equal to 75.0 milliliters?
- When the snail was racing the dog, the snail moved 85 centimeters, while the dog moved 50 meters. Convert 85 centimeters to meters in order to compare the distances each animal traveled.
- The lab experiment asked for water to be measured in liters, but the students only had a graduated cylinder with milliliters measurement lines. Convert 0.98 liters to milliliters, in order to complete the experiment.
- Susy was going to knit a sweater and needed to figure out how much yarn she needed to complete the project. The directions said she needed 39 meters but her ruler was in centimeter units. Convert 39 meters to centimeters in order to complete the measurement.
- Susy was learning to use a scale to record mass and accidently recorded the mass of a lab sample in kilograms. The units required are in grams. Convert 0.357 kilograms to grams in order to complete the lab experiment.
- Jimmy’s cat is on a diet of and is limited to only 8.95 grams of food per meal. The cat food can indicates the food quantity in milligram units. Convert 8.95 grams to milligrams in order to feed the cat accurately.
- Last night it rained and Marissa wanted to measure how much rain fell into her rain barrel. Her rain barrel has units of kiloliters, but Marissa is not familiar with kiloliters and wants to convert the amount to the familiar amount of Liters. Convert the recorded value of 4.145 kiloliters to liters.
Dr. Shade has been researching how different shade structures block UV rays from overheating playgrounds. She thinks she has found the perfect shade structure that is the right thickness, width and length to protect all kids while they play outside. However, she collected all her research in standard units rather than metric units. In one week, Dr. Shade has to present her findings at a scientific conference, but she has a problem… All scientists speak the universal language of metric units.
Help Dr. Shade convert all her measurements to metric before the conference and help kids around the world play outside more!
|Thickness of the cloth||0.25 inch||2.54 cm = 1 inch||centimeters (cm)|
|Width of the cloth||23 feet 5 inches||2.54 cm = 1 inch||Meters (m)|
|Length of the cloth||10 feet||2.54 cm = 1 inch||Meters (m)|
Extension: Design a Better Lunch Tray
For years, students have complained to the school cafeteria about their food not fitting on their trays. Either the food spills over the sides of the divider into the other sections or the sections are not big enough for the food items they really love (like pizza!) The cafeteria staff is giving you a chance to redesign a food tray that is student friendly and will contain each food item without it spilling into the next section space.
Part I: Drawing
- Your drawing should be on an 8.5 x 11 piece of graph paper.
- It should include the scale for your tray. example: 1 cm= 2.54 inches
- An explanation for why you choose the scale that you did, the use of each section of the tray and why it is better than the current tray.
- Calculate the actual dimensions (based on your scale) of the tray and record them.
Your tray should meet the following requirements:
- Be larger than 5cm.
- Includes a section for a protein, vegetable, fruit, milk and snack.
- Easy for students to carry.
- Cannot be the same size as the current tray used at school.
- You will need to scale your design from a piece of paper to a model tray.
Things to remember:
- Food comes in different sizes so keep that in mind when you are designing.
- You can research different trays available.
Part II: Building (optional)
- Build your tray according to the scale and design recorded on your drawing.
- Use the material provided by your teacher, or those that you have available.