Force meters measure the weights of different masses. You can make a force meter with a few household objects. This activity is useful in classroom and home school environments. Ask students to make predictions about the mass of different objects. The students weigh the items and determine if their predictions are accurate. Students weigh each object and record the weight in Newtons, e.g. one medium apple weighs approximately 1 Newton.

## Construction

Measure a piece of cardboard and cut it into a rectangle with 4 cm by 8 cm (1 and 3/5 inches by 3 and 1/5 inches) dimensions. Cut a second piece of cardboard into a 2 cm by 2 cm square (4/5 inch square) and set aside.

Lay the rectangle on a flat surface and use tacks or a stapler to attach the elastic band to one side. When you hold the force meter upright, the band will hang down.

Form the paper clip into a "hook" shape on one end. The top of the paper clip remains the same.

Attach the top of the paper clip to the bottom of the elastic band. The "hook" will hang down.

Draw an arrow on the 2 cm by 2 cm (4/5 inch by 4/5 inch) square.

Poke the hook of the paper clip through the smaller cardboard square.

## Calibration

Hang a large piece of poster board on the wall. Use this for a chart to measure Newtons.

Hold your meter upright, standing by the poster board to calibrate it. Do not place any masses on the meter.

Look where the arrow points on the poster board and use a pen to mark this location. Label this "0 N" to represent 0 Newtons.

Add an object that weighs 1 Newton to the force meter. Assess where it falls on the poster board and mark this as "1 N" for 1 Newton. Continue measuring and marking for 2 through 5 Newtons.

Measure unknown masses and determine how many Newtons each object weighs.

#### Tip

Record predictions and results on a separate sheet of paper.