In this STEM activity, students will learn about tension as a force and how it acts on structural components through a hands-on group design problem.

Through this activity, the students are excepted to learn about force and tension and their balancing. When the ends of the thread are tied to the pencil and the nail, a tension will be created on the string and as a result, the pencil cannot fall on the side opposite to the nail where it is tied. But, still, it can fall on the remaining three sides. So, now if we tie a thread to these remaining three sides, the force or tension created by the threads will be balanced and pencil will be able to stand upright.

For their final task students will be instructed to balance a pencil upright with the help of the given materials.

Sample video of the final task: https://youtu.be/IlnkYlTOlb8

**Objective**: Introducing Class 4 & 5 students to the concept of Tension force.

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## Step 1: The Tug of War:

Students will be taken to the field for a three-round Tug of War game. The three rounds will be played as follow:

**Round 1**: There will be an equal number of students on each side.

**Round 2**: Team A will have a lesser number of students.

**Round 3**: Team B will have a lesser number of students.

## Step 2: Assessment:

**Post-Activity Reflection**: Students will be given five minutes to reflect on the activity and think about how and why the number of students in a particular group affected the outcome of each round. Then together as a class, the teacher will go around the room having students one-at-a-time name items on their lists. Discuss and write the ideas on the board, until no new ideas are presented.

**Possible answers**:

1) When the number of students was equal on each side, the round took longer to complete.

2) When the number of students was unequal, the team with more number of students wins.

3) More students = More force

4) Equal and opposite force cancels each other.

The teacher will then introduce students will **Tension force**:

The *Tension Force *is defined as the force that is transmitted through a rope, string or wire when pulled by forces acting from opposite sides. The tension force is directed over the length of the wire and pulls energy equally on the bodies at the ends.

**Post-Introduction Reflection: **Students will be given five minutes to think of five real-life examples of structural elements in tension, and write them down on paper. Then together as a class, the teacher will go around the room having students one-at-a-time name items on their lists. Discuss and write the ideas on the board, until no new ideas are presented.

**Possible answers**:

Chandelier light hanging on the ceiling through a rope, cables (wire ropes) that hold up bridges, wire fences, flag hoists; telephone and cable lines hanging between poles and houses, ropes with pulleys that lift heavy loads, elastic bands and guitar strings, cable car, etc.

## Step 3: Here Is the Challenge:

For the final task, students will be challenged to balance a pencil upright on the table using the given materials.

**Supplies for the task:**

1) Cardboard

2) Scissors

3) 4 Nails

4) Hammer

5) Pencil

6) Cotton Thread(2 foot)

7) Wooden piece (20x20cm)

**STEPS:**

**Step 1: **With the help of an adult, students will cut a circle(radius 6cm) out of cardboard.

**Step 2:** Placing the circle on the wooden piece students will hammer 4 nails on four sides of the circle.

**Step 3: **Students will now try to balance a pencil at the center of the circle using thread and nails.

You can find a sample video here: https://youtu.be/IlnkYlTOlb8

## Step 4: The Tower:

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Classroom Science Contest

## 2 Discussions

Question 7 weeks ago

If I used pushpins and corriflute (plasticized cardboard), do you think it would hold? I don't have it on hand to test it at the moment but I was wondering how much tension was needed.

Answer 7 weeks ago

It will hold as long as tension from all sides is equal. I haven't used corflute yet but if it could hold the pushpins firmly, it will do. Thanks !