What they learned
DNA is only about 50 trillionths of an inch long. The reason it can be seen in this activity is because students are releasing DNA from a number of cells. This happens when the detergent or dishwashing liquid breaks, or lyses, the membranes around the cell and around the nucleus. Once released, the DNA from the broken open cells intertwines with DNA released from other cells. Eventually, enough DNA intertwines to become visible to the eye as whitish strands. One strand of DNA is so thin (.0000002mm) they would never be able to see it without using a microscope.
Source: Nova Teachers at PBS.org
Science can be fun — and it isn’t just for guys.
That’s the message behind a Girl Scout program called STEM, which stands for science, technology, electronics and math. This summer the Great Bend Public Library is offering STEM activities for teenage girls and boys. Activities take place at 2 p.m. on select Thursdays in the library’s Teen Spot.
GBPL’s Young Adult Library Jennifer King leads the activities, using materials and lesson guides provided by the Girl Scouts.
The first week, King asked the teens to draw a picture of what a scientist looks like. “Every single girl drew a man,” she said. The STEM program is intended to end that stereotypical thinking.
Last Thursday, teens extracted DNA from bananas during the STEM activity “Imagine Yourself in a Lab.” Then the research teams moved on to food science and created vinaigrette flavoring, which was dipped in bread.
Extracting DNA was a fairly simple process. The forensic lab made use of everyday items such as mild dish washing liquid, salt and a small amount of rubbing alcohol. After preparing a solution, teens slowly swirled their bananas in it. Most of the DNA precipitated out of the soap solution, leaving behind strands that wrapped around a toothpick and were visible to the naked eye.
The vinaigrettes were creates at a “flavor station” when two-person teams decided what to add: Salt, pepper, dill weed, Mediterranean oregano, garlic powder or rosemary.
This week’s STEM topic is “Imagine Yourself as an Engineer.” Students will work with electric circuits to create game-show buzzers. Then they’ll use the buzzers in a contest.
“Imagine Saving the Planet” will be the topic on July 10.