# Speed Rolling Down A Ramp | Smart Science Projects

### Project Overview:

This project will teach you how to use BOSON light sensors to make a timing gate that measures the speed of a rolling ball. Then you can apply the same method on a ramp, to test out the famous Galileo's inclined plane experiment.

### Background Knowledge:

The light sensor measures light intensity. We use light sensors in this project to detect the ball passes by based on a drop of light value.

Place the sensors every 10cm (Distance).

Record the time of the ball passing through the sensors respectively, then calculate the interval time by time2 - time1(Time).

We can get the average speed of the ball with: Speed = Distance / Time.

### Build the Model : Horizontal Track

The horizontal track is a simple model to explain how to measure the speed of a rolling ball. It consists of 2 light sensors placed 10cm in between and plugged into a micro:bit to collect and visualize the data in a Mind+ program.

Cardboard Sheet

#### Hardwares:

1 Micro:bit + Extension Board

2 BOSON Light Sensors

#### Making Steps:

1.Prepare the long sides of the track from cardboard. Cut out 2 slots about 2.5cm x 1cm for sensors 10cm apart.

2.Prepare the bottom in the same length of the side and 2.5cm wide.

3.Prepare the short sides 2.5cm wide and higher than the track to stop the ball from rolling.

4.Glue everything together.

### Activity 1: Measure the Speed on A Horizontal Track

Download the sample program 1 and open it. Click connect hardware on the top and choose micro:bit port. (If there is no micro:bit port showed up, try to re-plug the micro:bit to your computer.)

Click the green flag to start the program.

In this program, the distance is set to 0.1m. After the ball passes by and get t1 and t2, the speed will be calculated automatically.

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### Build the Model : Inclined Plane

After understanding how to measure the speed, you can apply the same method and upgrade the model into a inclined plane. The model uses a button to start timing, and places 3 light sensors to measure the average speed of three sections.

Cardboard Sheet

#### Hardwares:

1 Micro:bit + Extension Board

1 BOSON Button Sensor

3 BOSON Light Sensors