DIY SPF Testing — Munchkin Fun At Home (2024)

Materials

• 3-4 containers (foil, shoe boxes, etc)

• Plastic wrap

• Tape

• UV beads (like these)

• Sunprint paper (get here)

• Sunscreen with different SPFs

Directions

1. Put your containers in the shade. Fill with UV beads and pieces of sunprint paper. If you’d like, tape materials so they don’t move around.

2. Using a different SPF for each box, smear sunscreen on the UV beads and sunprint paper. Leave one box sunscreen free.

3. Cover the top of the containers with plastic wrap.

4. Place your containers so that they receive direct rays from the sun.

5. Check your containers every 30 minutes. Compare the color of the testing materials.

Why it Works
The SPF number is supposed to be an indication of how long the sunscreen is effective. To determine this in minutes, multiply the SPF by 10. For example, SPF 30 = 300 minutes (30 x 10), or 5 hours. The height of the sun affects the amount of radiation received. If the sun is really high in the sky the UV radiation received by your skin is greater than when the sun is lower in the sky.

Adapted from CuriOdyssey