This was an adorable project, especially with the timing of Mother's Day, but we did struggle to keep the heart models inflated for an extended period of time.  Eventually we decided it was better to make a model that could be  re-inflated when it went flat.

If you have a heart model that is fastened together with heavy tape, you can change it easily to rubber bands.  Just pull off the tape, and any foam that is wrapped around the ends of the tubes.

Strawberries are the perfect choice for a DNA extraction lab for two good reasons: (1) they have much more DNA than other fruits, and (2) they are octoploid, meaning that they have eight copies of each type of DNA chromosome.

1. Put a bottle of isopropyl alcohol in a freezer. 
2. Measure 6T (90 ml) of water into a small glass container.
3. Add 2 tsp (10 ml) dish soap to the water.
4. Stir in a ¼-tsp salt and mix until the salt dissolves. This is the extraction mixture.
5. Place one strawberry into a plastic zipper-lock bag.
6. Pour the extraction mixture into the bag with the strawberry.
7. Remove as much air from the bag as possible and seal it closed.
8. Use your hands and fingers to mash, smash, and moosh the strawberry inside of the bag. You don’t want any large pieces remaining.
10. Pour the resulting strawberry pulp and extraction mixture through a strainer and into a medium glass bowl or similar container.
11. From the container it’s in now, pour the extraction mixture into a smaller glass container that holds ¼- to ½-cup (50-100 ml) of fluid. This will help to isolate the DNA on the surface of the mixture.

12. Add 1 tsp (5 ml) of the chilled isopropyl alcohol to the solution and hold the mixture at eye level. The white layer that forms on on top is the DNA of the strawberry!  It may take a minute or two for the DNA to develop, so wait patiently. 

Don't stir the mixture at this point, or the DNA will fall apart again.  You can gently scoop it out with a toothpick.