From Girl’s Life Magazine, courtesy of GSUSA

Women are needed in the engineering profession, yet research shows that girls and young women lose interest in subjects and the fields of study leading to engineering careers long before they enter college. For National Engineers Week 2004, the engineering community is encouraged to participate in “Introduce a Girl to Engineering Day” with a goal of 125 organizations mobilizing 11,000 women in engineering reaching more than one million girls. Introduce a Girl to Engineering Day, now in its fourth year, is slated for February 26. One of the week’s star activities encourages engineers to make the world of engineering come alive for girls. Since its inception, an estimated one million girls have experienced engineering firsthand each year, with more than 110 organizations participating in 2003. Programs ranged from 20 girls working with members of the National Society of Black Engineers’ North Carolina State University chapter to 3,000 girls reached by the New York State Department of Transportation in Poughkeepsie. The Sightseers Guide to Engineering (www.engineeringsights.org), created by the National Society of Professional Engineers in 2001, continues to draw fans. Celebrating engineering marvels from subtle to spectacular in all 50 states, the site invites the public to recognize and appreciate the achievements of America’s engineers. Visitors can even submit their own favorites. Another Web site, discoverengineering.org, launched in 1999, is also still going strong. With information targeted to middle school students on the how and why of becoming an engineer, the site uses such wonders of engineering as roller coasters and CD players to pique the interests of young people and includes hundreds of links to related educational, professional, and corporate sites.
A further outreach to young people is DiscoverE, part of the eweek.org Web site, is aimed at K-12, it continues to provide thousands of engineers with quality educational materials that help them reach more than five million students and teachers every year through classroom visits and extracurricular programs.

Activity

What are batteries? Within a battery, a chemical reaction takes place between an electrolyte and electrodes. Batteries come in two categories: dry cell and wet cell. Dry cells (such as flashlight batteries) are the alkaline batteries that use a powder chemical for an electrolyte; wet cells (such as car batteries) use acids as the electrolyte. The girls will create a wet cell battery using the juice of a lemon, which is a mild acid, as the electrolyte.

Give each group a D-size battery, a lemon, a copper electrode, and a zinc electrode.

First press down on the lemon and roll it on the table to get the juices flowing inside.

Insert the zinc electrode into the lemon so that approximately half of the electrode is still protruding out.

Do the same with the copper electrode. Space the electrodes about 3 or 4 cm apart.

Set the multimeter to read DC voltage, and measure the voltage of the battery. The battery voltage should read approximately 1.5 volts. Show that this is written on the side of the battery, confirming that the multimeter works properly. Read the voltage across the electrodes of the lemon battery. The multimeter should read approximately 1volt.

Set the meter to read DC current, and take the reading across the electrodes of the lemon battery. The reading will be approximately 0.0001 Amperes. Ask a recorder to put this reading in a separate column labeled “I” on the board.

Take readings from each group and average the readings.

Multiply the average voltage (V~1.0 Volt) times the average current (I~0.0001 ampere) to find the average power (P~0.0001 watt) delivered by the battery.

It takes 100 watts to power a 100 watt light bulb. The more the wattage, the greater the power consumption. Calculate how many lemon batteries would be required to power the 100 watt light bulb [Answer: 100 watt / 0.0001 watt = 1 million (1,000,000) lemon batteries].

An electric car requires 6000 W of power to run. Calculate how many lemon batteries would be required to power the electric car. [Answer: 60 million (60,000,000) lemon batteries, employing 60 million lemons!]

Does it make sense to use lemons to power a car? What are some of the pros and cons?
Pros - Does not pollute, renewable energy source, electric cars are quiet, etc.
Cons - Cannot recharge lemons, heavy, expensive (25 cents per lemon = $15 million)

Credits: This activity was provided by IBM research engineers who invite girls to see what’s going on at www.research.ibm.com.