Diffusion Lab

If you would like to check out the lab worksheet I used for this lesson,

you can find it on my TPT store.

Grab your items. For this lab you will need the following:

Starch- You can also buy this from your local supermarket or check with your local chemistry teacher.
Lugol’s Iodine Solution
Dialysis Tubing
- I used reagents from Carolina- Here are the links to their products
Plastic Cups or beakers
- Any type of container will work for this lab
Plastic spoons
Scissors
Ruler
Disposable Pipettes

(Tip: Setup lab stations before students arrive to your classroom)

Dialysis Tube Baggies

Students will get Dialysis tubing from their teacher. (Tip: Precut 2 feet pieces of tubing per group).Students will cut a 10 inch piece of dialysis tubing to prepare their dialysis baggie. They will make a knot on one end and fill the baggie 1/2 way with water. Then, they will add 1 teaspoon of Starch into the baggie and make a knot to close the baggie.

Once the baggies are ready, students will get a beaker/cup and fill it 1/2 way with water and add approx. 15 drops of Iodine (Lugol's Solution). The baggies will be placed inside the beaker and after approx. 20 minutes, students will come back and record their final observations.

(Tip: Students should be wearing their personal protective equipment PPE for all labs. Lugol’s Iodine Reagents will stain hands and clothing and cause skin rash. If ingested it can cause abdominal problems.)

Tutorial Video

Here is a video for both teachers and students that shows how to prepare a dialysis baggie. Baggies can be used for both Osmosis or Diffusion Labs.

Diffusion Results-Wow!

Students will be amused and question why the baggie turned purpled. They will discuss in their groups “How was the dialysis tubing that contained starch affected when placed inside the beaker with water?” Students will use concepts of selective permeability and tonicity to explain their overarching results from this Diffusion lab.

If you would like to check out the lab worksheet I used for this lesson, you can find it on my TPT store.

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