Doppler 9&10 STEM: A Banana Has DNA?
Teachers & Parents:
Does your kid have a science question?
Have them send us a video with a weather question to firstname.lastname@example.org!
Today’s experiment is special because it is inspired by our research on an important figure in the STEM world. Her Name is Dr. Rosalind Franklin.
Dr. Franklin was a Physical Chemist in the 1950s and was the first person to capture an image of the shape of DNA which led others to discover its function, carrying instructions to cells so that our bodies can make more cells.
If I told you bananas had DNA would that surprise you? How about this: did you know you can extract (separate) the DNA from the banana and it is not that difficult. Parents, you will need to be around for this one!
So here is what you will need for today’s experiment:
- Warm Water
- Blender (optional)
- Coffee Filter or Strainer
- Mason Jar or Glass Jar
- Rubbing Alcohol
- NEED A PARENT: Mom or Dad, help the little ones cut the banana into several pieces
- Sprinkle salt on the banana pieces. This is to keep DNA intact. 1 teaspoon should be fine
- We need to mash up the banana pieces now, a blender is the best way to do this
- Blend the bananas for 10 seconds, you do not want a runny mixture
- Place a coffee filter or strainer over your glass cup or mason jar
- With the strainer on top, pour the blended banana/salt mix into a mason jar or glass jar until the glass is half full
- Lightly add some liquid soap to the banana and mix it
- Pour your COLD rubbing alcohol into the glass slowly
- Make sure there are TWO distinct layers forming. One should be the banana mix, the alcohol should be on top (different density)
- After you have poured alcohol to the top, WAIT about 5 minutes for the DNA to separate from the banana mix
- After 5 minutes are up, use a toothpick to extract the DNA
- Twist the toothpick SLOWLY when you pick up the DNA
- DNA should be easy to spot: stringy and long near the top of the glass
Here is what happens:
We are breaking down DNA from a banana. The reaction between the soap and the banana mixture causes cells to “break up” and release the DNA of the banana. You can try this experiment at home and test different types of food as well!
If your kiddos try this experiment, send us photos of you and your experiment and you might get to see it during weather on The Four on Tuesdays!
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