Objective: Make a 3D model of a cell
Constraints: 10 kids, 30 minutes of class time
The original project required Sculpey, which you have to bake. I found a great alternative: Plastalina, an oil-based modeling clay. No baking required, and it doesn’t dry out. A multi-color pack is super cheap, I got mine from Michaels.
Ping Pong ball
1 multi-color pack of plastalina
clear polymer “gems” from the floral section
- Hydrate the polymer gems. I dumped mine in a gallon ziploc bag with a couple of cups of water and let it go overnight. My package was probably only 2 teaspoons of crystals before hydrating. It takes a couple of hours before they reach full size, so I suggest doing this in advance. When they’re ready, put the polymers in the fishbowl but don’t put additional water in yet. This is your cytoplasm.
- Take your ping pong ball and cut out a wedge-shaped piece. Basically, turn him into Pac-man (mouth WIIIIDE open). This is your nuclear membrane, so you need a cutaway opening big enough to show the DNA inside.
- A note about plastalina: it’s pretty stiff when you open the package, but if you knead it for a while it becomes pliable. It also will roll really, really, thin, so don’t be afraid to spread it out. If you keep it too thick, your pieces will be too heavy. THAT BEING SAID: knead some blue plastalina and then cover the exterior of your ping pong ball with a thin layer.
- Using your RSO guide, start making the various organelles. An excellent illustration guide can be found here: Blausen Medical Guide. Repeat this chant: “The mitochondria are the powerhouse of the cell.” (It comes up again later. A lot.)
- When all your cell bodies are made, start suspending them in your fishbowl. A chopstick or the handle of a paintbrush is very handy here, to help position everything where you want it. Those free ribosomes can be sneaky!
- Once you have everything positioned the way you want, start adding water to the fishbowl. When you’re done, it should look like your cell bodies are all suspended in cytoplasm. Cover the bowl with cling wrap and enjoy!
Advance prep for a coop group: gather your materials and hydrate the gems overnight.