Get your students up and moving with our interactive 1 Kilogram Hunt: Mass Worksheets! This hands-on investigation is designed to develop your students’ understanding of mass through real-world comparison and estimation. By using their senses, observations and reasoning skills, students will explore and estimate which classroom items weigh approximately one kilogram, and then confirm their guesses using scales.

This activity makes abstract measurement concepts feel more tangible and accessible for young learners. By physically lifting and comparing everyday items, students gain practical experience with the weight of 1 kilogram. They also learn how estimation and measurement tools work hand in hand to improve accuracy and understanding. This resource is a perfect fit for early years and lower primary mass units and can easily be adjusted to suit your classroom needs.

Each student begins by identifying an anchor item that is known to weigh exactly one kilogram. Using this as a reference point, they search around the classroom for other items that feel similar in mass. Once they’ve made their selections, they use digital or analogue scales to record and evaluate the actual mass of each item, comparing their estimation to the true value. This mix of prediction and verification promotes mathematical thinking and supports the development of key mass-related vocabulary.

Key Learning Outcomes:

• ✅ Identify and estimate the mass of everyday classroom objects
• ✅ Compare items based on tactile observation and reasoning
• ✅ Measure mass using standard measuring tools such as digital or analogue scales
• ✅ Strengthen estimation skills and develop accuracy in measurement
• ✅ Record and reflect on comparisons between estimated and actual measurements

What’s Included:

• Two differentiated worksheet versions:
  • - Version 1: Fewer items to estimate and larger space for illustrations or written descriptions
  • - Version 2: More items to find with additional recording lines for older or more advanced learners
• Student-friendly table format for recording estimates and actual mass measurements

Materials Needed:

• Printed worksheets (Version 1 or 2, depending on student level)
• Reference item known to be 1 kilogram in mass (e.g. 1 kg bag of rice)
• Scales (digital or analogue) for measuring mass
• Pencils or markers for writing or drawing
• Optional: tubs, bags, or boxes for collecting classroom items to compare

How to Use:

1. Introduce or revise the concept of mass and the unit kilogram using classroom visuals or real items.
2. Show the 1 kilogram reference item and discuss strategies for estimating other objects’ weights based on feel and comparison.
3. Distribute the worksheet version appropriate for each student.
4. Students find and record several classroom items they believe are close in mass to 1 kilogram by feel alone.
5. Using scales, students measure and record the actual mass of each item and reflect on the accuracy of their estimates.

Ideas for Classroom Use:

• 💡 Use during a Maths rotation station as a practical measurement task
• 💡 Combine with a science lesson on properties of materials or forces
• 💡 Create a classroom display comparing predicted vs actual masses
• 💡 Challenge students to bring in a home object they believe weighs 1 kg and test it together

Top Teacher Tips:

• 💛 Print worksheets on A3 for younger students or for group collaboration
• 💛 Discuss estimation techniques beforehand, such as using both hands to feel balance
• 💛 Use a range of unusual and surprising items to make comparisons more engaging
• 💛 Model how to zero and use both digital and spring scales before the activity begins

1 Kilogram Hunt: Mass Worksheets offer a fun, tactile and educational way for students to deepen their understanding of mass while learning to make and test estimates using real-world objects and measurement tools.