Time: 45 min
Students will be able to :
- Explain that melanin gives skin color
- Explain that the amount of melanin is what makes skin darker or lighter
- Discuss whether melanin makes us different
- Small paper or plastic cups (enough for class)
- Unsweetened lemonade or another unsweetened drink, water could work too (enough for class)
- Something to stir lemonade
- Spoon OR One set of measuring spoons
- FOR VARIATION (see Guided Practice): 3 jugs of pre-mixed lemonade of varying sweetness.
- PDF download of lesson plan
*Set up things before students arrive to make the lesson flow smoothly. Pour the lemonade when giving it to each student or prepare them before class.
*If there is a sugar-sensitive student, you can have him/her work with another student and be a “journalist” and ask the student questions about what the drink tastes like as the sugar is added.
1. At the end of the Introduction to New Material, assess whether students understand that melanin gives skin color by asking review questions.
2. During Guided Practice, assess whether students are able to understand the logical flow and connection between the experiment they just did and skin color.
3. During Closing, assess whether students have understood material by
asking review questions.
4. During Closing, assess whether students are able to thoughtfully discuss skin color.
1. Explain that throughout history, there has been a lot of discussion about skin color and what it means. Sometimes people are treated differently because their skin is a different shade, but really, it’s just science that makes us have different skin color. What is the real reason we have different shades of skin? It just comes down to something called melanin.
Introduction to new material
1. Tell students to repeat after him/her: “Melanin.”
2. Explain some people call it pigment, and it is what gives our skin color.
3. Ask students, “So what gives skin color?”
a. Students should say “melanin.”
Materials: Paper, pencils, unsweetened lemonade (or lemon water), small paper or plastic cups for students, spoon/straw (something to pour sugar and something to stir lemonade), and sugar
1. Break into pairs or groups and explain the activity.
a. Each person is going to get a small cup filled with lemonade.
b. Each pair or group will put sugar in their cups.
c. Students will write down two things: What they are drinking and how sweet it is.
d. Then students will come up to the teacher again and repeat. This will happen a total of three times. Students should have a total of three observations written down with the drink they are drinking and the sweetness of it written each time. Students’ work should look
something like this:
i. I am drinking lemonade. It is not very sweet.
ii. I am drinking lemonade. It is kind of sweet.
iii.I am drinking lemonade. It is very sweet!
e. VARIATION: Instead of having students come up front to add sugar, you can have 3 jugs with pre-mixed lemonade of varying sweetness and just pour a little in each cup when students come up during each trial.
2. Put a very small amount of sugar (if s/he has measure spoons, it might make it easier) in students cups the first time. A medium amount the second time. The last time put in a lot of sugar. Make sure the lemonade gets sweeter each time. Test your own glass before giving to students.
3. After all three trials are done and students have written down their sentences, ask what they wrote down for each time they added sugar.
a. What were they drinking on the first trial? How sweet was it?
b. Repeat for second and third trial.
4. Ask, “So, even though we kept adding sugar, it was still lemonade every time?”
a. Students should respond, “Yes”
5. Ask, “So then, even though something changed, it was still just lemonade?”
a. Students should respond, “Yes.”
6. Say, “Well this is just like skin. The lemonade is just like skin and the sugar is just like melanin. What does melanin do again?”
a. If students do not know, remind them that it gives skin color.
7. Ask, “So what did the sugar do to the lemonade? If we had more or if we had less?”
a. Students should respond that is makes it sweeter.
b. If students do not know, then ask a pointed question like, “Did it change the taste somehow? How?”
8. Say, “Sugar gives lemonade sweetness depending on how much there is. So if sugar is like melanin, and melanin gives skin color, what will it do to skin color depending on if a person has more or less melanin?”
a. If students cannot come to the conclusion that it will make skin darker or lighter, ask a direct question like, “Will it change the shade? Do you think it could change the color?”
1. Ask students if they can tell him/her what gives skin color.
2. Ask if anyone can explain how melanin works or what it does.
3. Ask students what they think now that they know the only thing that makes someone’s skin darker than another’s is melanin.