Wednesday, July 23, 2014

Sweet Science: Strawberry DNA Extraction Lab!

Science at the park! A DNA Extraction lab on a crisp fall day.
Photo Credit: Alex Gregory, ASU Photojournalism student

One of our favorite biology labs to do is the DNA Extraction Lab. We've been doing this activity since my daughter was 4 years old, and it is a fantastic and fun way to get a closer look at the tiny world inside of us!

DNA exists inside of every single cell in our bodies, as well as every living cellular organism (that we know of) on Earth. You can think of DNA as the "code" that lets our cells know what job they have, and what category of tissues they belong to. Some cells are coded to be a part of our eyes, while others are coded to be a part of our muscle tissue. Every cell is encoded with DNA, even red blood cells, bacteria cells, and skin cells! 

DNA is one of the most important foundations of life on Earth, but it's so small, it's impossible to see! It's also locked in tight within the cell's nucleus, protected against contamination and corruption. However, there is a way where you and your kids can isolate the DNA out of cells, extract it, and see it for yourselves!

Photo Credit: Alex Gregory, ASU Photojournalism student

Note: For our day of science in the park, we made a HUGE batch of strawberry DNA. For results in the photos, multiply the ingredients by 5!

Materials Needed:

1. 2 Strawberries (bigger is better!)
2. 180 ml (2/3 cup) of water
3. 15 ml (1 Tbsp) of liquid dish soap
4. 2 g (2 Tbsp) salt
5. 10 ml (2 Tbsp) cold 91% isopropyl (rubbing) alcohol
6. Strainer
7. Cup
8. Fork
9. Ziplock bag
10. Safety Goggles

Note: The night before you do your lab, put your bottle of isopropyl alcohol in the freezer. While it won't freeze, the colder the alcohol gets, the better the DNA extraction works. 


1. Put on your safety goggles!

2. Combine your water, salt, and dish soap in a cup. Gently stir to thoroughly mix the ingredients.

3. Put your strawberries in a plastic bag. If they are frozen strawberries, make sure to thaw them first!

4. Add your salt, water, and dish soap to the bag. Close the bag, and make it as air tight as possible.

Photo Credit: Alex Gregory, ASU Photojournalism student

Here's the fun part - MASH YOUR STRAWBERRIES!!! Mash them with gusto! Keep mashing them with until they become foamy and everything has blended together into a pulpy liquid.

6. Put your strainer over your cup and carefully pour your strawberry mixture through the strainer. You can use your fork to press down on the strawberries, getting as much pulpy liquid into the cup as possible.

Photo Credit: Alex Gregory, ASU Photojournalism student

Slowly pour your cold isopropyl alcohol into your strawberry liquid. Wait approximately 2 minutes.
You should begin to see some white strands form over the top of your mixture. This is DNA!

8. Take your fork and slowly skim the surface of your liquid. You'll be able to pull out a large clump of pink and white material. This gooey substance is strands of DNA mixed with the broken proteins that held it all together!

Photo Credit: Alex Gregory, ASU Photojournalism student

While you still won't be able to see the double helices themselves, you can see the long strands that contain them! Take a small sample of your strawberry DNA and put it on a glass slide, with a slip cover on top. Put it under your microscope and take a look! That's DNA!

Photo Credit: Alex Gregory, ASU Photojournalism student
How It Works:

So how did this all come together, anyway? Well, using strawberries is actually really important for this lab! Commercially grown strawberries are known as "octoploids", meaning they contain 8 pairs of chromosomes! By comparison, humans have 2 pairs per cell. They also contain special enzymes (pectinases and cellulases) that help break down the cell walls. So, while any fruit will work, commercially grown strawberries will give you a much better yield of DNA!

Now let's get into the mixtures we used. The soap helps break down the thick cell walls of the strawberries. The salt (sodium chloride) helps break apart the protein chains that are bound to the DNA. It also helps keep them dissolved within the water, so they don't reattach themselves to the DNA strands. When you mash the strawberries, you're really working to break apart those cells and get that DNA out of there!

The alcohol plays a very important role in this lab. DNA is not soluble in alcohol, which means that it won't dissolve. The colder the alcohol is, the better this works, which is why it's important to stick it in the freezer the night before (in a closed container please!). The alcohol is also less dense than water, so it will automatically rise to the surface, carrying the DNA with it!

There are other DNA extraction labs that you can conduct in your home. You can collect a sample of your own DNA by swabbing your cheek cells! Here is a link to a great tutorial for a cheek cell lab.

You can also make your own jewelry with DNA! Just take a small microcentrifuge tube, and put your DNA in there. You can tie string to it, make a beaded necklace, or you can make a bracelet or earrings with it!

Here's a print out of our strawberry DNA extraction Lab. Just right click, save, and print!

Image Credit: Amy and Kat Oyler

We'll be taking our DNA extraction lab to the kids at our local library, where they'll not only get to extract strawberry DNA, but they'll also get to make their own jewelry with it! It's such a fun and easy way to get a closer look at the biological wonders around (and within!) us. I can't wait to share this with the kids in our community!

If you're in the Phoenix area and would like to come extract DNA with us, here's the info! You can also find it listed with The Arizona SciTech Festival!

What: Strawberry DNA Extraction Lab and Jewelry Making!
Where: Burton Barr Library (the big downtown library on Central and McDowell!)
When: Tuesday, July 29th, from 2-4pm.
Who: The Scientific Mom, MACH1's Terry Ann Lawler, and The Scientific Kat!
Why: Because science is AWESOME!

A happy end to a wonderful day!
Photo Credit: Alex Gregory, ASU Photojournalism student

Happy Exploring!

Wednesday, July 16, 2014

Dancing in Rainbows: Blasting Off In Light and Space!

Lately we've been spending a lot of time learning about the planets in our solar system, and thinking about the universe at large. New star systems are being discovered all the time, and it seems like every few months, we're hearing about another new Earth-like planet! We have some ideas as to what the atmospheres may be like on these planets, and we know a lot about what makes up the planets and moons in our own solar system. The big question we had was, if we haven't been to these planets and other terrestrial bodies, how on Earth do we know what they're made of?

How do we know what's out there?
Image Credit: CC Wikipedia

Thursday, April 17, 2014

Let's Take A Trip Through The Cardiovascular System!

Check it out, we made a heart!

For the past two weeks, Kat and I have been learning about the cardiovascular system and how it works to keep our body alive and healthy. We've done some really great projects to demonstrate how the heart works, and we've even dissected a pig heart in our home! All of this will culminate into a visit with the American Red Cross, where we will learn more about human anatomy relating to the circulatory system, Kat will learn some basic CPR, and I will donate a pint of blood to the Red Cross!

In this post, I'll talk about how the heart works, and share some of the wonderful projects we've been working on as we learned about the heart!

Friday, March 21, 2014

Nick and Tesla's Robo Kitty Dog Distractor!

My daughter loves to read. Ever since she entered the world of chapter books and young novels, her voracious appetite for reading has been nearly unstoppable! Favorite books have been read and reread dozens of times, and I'm always looking for something new to sate her interests.

It came to my attention that one of our favorite TV Scientists, Science Bob had written a kids novel with Steve Hockensmith called "Nick and Tesla's High Voltage Danger Lab!". It's about two kids named Nick and Tesla who get involved in some pretty crazy adventures, and they use the power of science to navigate through them! We absolutely adore Science Bob, and his book looked amazing! I couldn't wait to get a copy for Kat. I asked Science Bob if he could send us a copy and much to our delight, he did! He sent us an autographed copy and even included this awesome girl power (with the periodic table!) shirt for Kat!

Monday, February 17, 2014

Adventures at the Arizona SciTech Festival: Hacking and Crafting!

The Arizona SciTech Festival is in full swing, which means that for the next two months, we're in for over 500 science related events throughout the state of Arizona! Events during the SciTech Festival include science experiments and activity days, robots and rockets, lecture series, open houses at ASU and various state parks, and all sorts of science throughout the Valley!

We decided to kick off our SciTech adventures at one of our favorite places in Phoenix, the Burton Barr branch of the Phoenix Public Library! We showed up on Wednesday to check out their Paper Engineering workshops.

Thursday, February 6, 2014

Getting Wild With Science at the Phoenix Zoo!

Let's take a behind the scenes look at the Phoenix Zoo!

Did you know that there is a place where your kids can learn about animals, how to take care of them, and get a behind the scenes look at the life of a zookeeper? The Phoenix Zoo offers an incredible lineup of classes for kids of all ages, where they can learn about veterinary practices, animal relationships and behavior, adaptations and bio-mimicry, habitats and conservation, and so much more!

With their Keeper for A Day, Nature Explorers, Breakfast with the Animals, and their Zoology classes for kids, the Phoenix Zoo is a wonderful place to for animal science. Not only can your kids learn directly from the people who take care of them, but they can also get some exclusive behind the scenes experiences with the animals themselves!

Sunday, December 29, 2013

You've Got A New Microscope!

Alright! So you've just bought you and your kids a brand new microscope, and you've already blown through the prepared slides they came with. Now what can you do? How in the heck do you take care of this thing? Are you supposed to clean it? What should you look at next? How can you enjoy this tool of scientific wonder to the fullest, and really get a great view of the tiny world of microscopic life all around you?

Let's begin by taking a look at how to care for your microscope...