A comparison on the ability of different brands of bicycle helmets to absorb shock
Materials required for this science fair project:
- A 2 meter long string
- 1 Giro Indicator bike helmet
- 1 Bell Influx bike helmet
- 1 Giro Ionos bike helmet
- A 3 kg circular weight (~100 mm diameter) with a hole in the middle
- 1 basketball to fit inside the helmet
- 1 air pump
- 1 pressure gauge
- 4 bricks
- 1 chair
- 1 assistant
1. The independent variable in this science fair project is the type of the bicycle helmet used. The dependent variable is the air pressure in the ball when the weight hits the helment, which is determined by measuring the maximum deflection in the air pressure gauge. The constants (control variables) are the height from which the weight was dropped, the mass and size of the weight, the size of the helmet, the size of the ball, and the initial pressure of the ball.
2. Three different brands of bicycle helmets will be used in this experiment. The Giro Indicator bike helmet is the cheapest, the Bell Influx bike helmet is middle-priced, while the Giro Ionos bike helmet is the most expensive.
3. Arrange the four bricks in a square and leave a small hole in the middle as shown in Figure 1. Pump the basketball to a pressure of 750 mmHg, and place it in the space between the bricks to prevent it from rolling away.
4. Secure the bicycle helmet over the ball as shown in Figure 1. Let the pressure gauge remain connected to the ball so that the increase in pressure can be observed.
5. Instruct the assistant to stand on the chair and hold the string vertically with the bottom end touching the center of the helmet, which will be the point of impact. Insert the tip of the string through the hole in the weight, and release the weight from the 2 meter height ,letting it travel down the string. Observe and record the maximum reading in the air pressure gauge. Repeat the test procedure for five times. Calculate the average reading and record it in the table given below.
6. Perform procedure 5 for all three brands of bicycle helmets. Record the average pressure reading in the table given below.
Caution should be taken to prevent the falling weight from hitting anyone