## Bernoulli Blower

**Sponsored by Jayden, Katelyn, and Mason Perez**

The easy physical representation of a scientific principle is a powerful way to teach young minds the science behind a phenomenon. When that representation is turned into a game, all the necessary elements of intuitive and self-motivated learning are in place. In this case, a fundamental principle of fluid dynamics is illustrated as a way to float a ball with a column of air. The only thing that can be changed is the speed of the air column by changing the diameter of the stream, but this then controls the height and stability of the floating ball. This exhibit both teaches the principle and also fine motor skills through trial-and-error

## Gear Up!

There are many ways to learn math, especially when it comes to things like multiplication, division, and ratios. The use of gears turns the study of ratios into a fun, challenging game both for the kids as well as for the parents. The use of a large driving gear as the basis to work three different sizes of gears, all in multiples of 6 allows for quick and easy learning by doing. The magnetic hubs also allow for stacking dissimilar gears for even more advanced learning. While easily learned without intervention, this exhibit becomes powerful when combined with very simple instructions and progressive challenges.

## The Maze

Mazes are one of the oldest forms of visual/logic challenges, and they have continued to be popular for a number of very positive reasons. They are not age limited as they appeal to a very wide audience. Depending on the scale of the maze, they test to varying degrees the subject’s ability to reason, remember, visually plot a path, test solutions, and even predict outcomes. Combined the tilting motion in two dimensions that is part of this exhibit, and you now are able to include both fine and coarse motor skills to the benefits mix, plus the aspect of teamwork and social skills. The simplicity of the exhibit again attracts users at all age groups, and there is no real need for instructional materials.

## Sample Activity for Educators

**Gear Up!: Finding the Gear Ratio of a Gear Train**

To be able to determine a gear ratio, you must have at least two gears engaged with each other- this is called a “gear train.” Usually, the first gear is a “drive gear” attached to the motor shaft and the second is a “driven gear” attached to the load shaft. There may also be any number of gears between these two to transmit power from the drive gear to the driven gear: these are called “idler gears.”

__Two-Gear Gear Train- What to do:__

- To find a gear ration, these two gears must be interacting with each other (their teeth need to be meshed and one should be turning the other.) I.E. big gear turns the little gear or visa versa.
- Count the number of teeth on the drive gear. One simple way to find the gear ratio between two interlocking gears is to compare the number of teeth they both have. Start by determining how many teeth are on the drive gear (the gear you’ll be turning manually). You can do this by counting the number of teeth.
- Count the number of teeth on the driven gear (the gear that will turn when you manually turn the drive gear).
- Divide the driven gear teeth by the drive gear teeth. Ex. The driven gear has 30 teeth and the drive gear has 20 teeth gets 30/20=1.5. This can also be written as 3/2 or 1.5:1 etc. What gear ration means is the smaller driver gear must turn one and a half times to get the larger driven gear to make one complete turn. This makes sense since the driven gear is bigger, it will turn more slowly.

__Three-Gear Gear Train- What to do:__

With more than two gears, the first gear remains the driver gear, the last gear remains the driven gear, and the ones in the middle become the “idler gears.” These are often used to change the direction of rotation or to connect two gears when direct gearing would make them unwieldly or not readily available.

- Pretend the two-gear train described above is now driven by a small seven-toothed gear. In this example, the 30-toothed gear remains the driven gear and the 20-toothed gear (which was the driver in the first example) is now an idler gear. (Remember: only the driver and driven gears matter, and the idler gears don’t affect the gear ratio of the overall train)
- In this example, the ratio would be found by dividing the 30-teeth of the driven gear by the 7-teeth of the new driver. 30/7= 4.3 or 4.3:1. This means the driver gear has to turn 4.3 times to get the much larger driven gear to turn once.

__Challenge- Determine the ration for the idler gears:__

You can find the gear ratios by starting with the drive gear and working towards the load gear. Treat each preceding gear as if it were a drive gear as far as the next gear is concerned.

- Divide the number of teeth on each “driven” gear by the number of teeth on the “drive” gear for each interlocking set of gears to calculate the intermediate gear ratios.