How many paper layers block a flashlight?
- 🙅 Never at faces
My hypothesis
If I change the kind of paper, then how many layers it takes before the light on the wall is gone will ______, because ______.
You fill in the blanks. Think about how much light a single sheet of each kind lets through, and what each extra layer does. A guess is a good because: the test finds out.
Change, measure, keep the same
CHANGE
the kind of paper: Tissue paper, Wax paper, Printer paper, Construction paper
MEASURE
how many layers it takes before the light on the wall is gone, in layers
KEEP THE SAME
- squares of paper cut to the same size
- adding one layer at a time
- the same flashlight, the same distance from the wall
- the same dim room, looking from the same spot
Scientists call the thing you change the independent variable and the thing you measure the dependent variable. The things you keep the same are the controls: if one of them changed too, you wouldn't know which change made the difference. Try each of the 4 levels 3 times.
What you need
- A flashlight
- Tissue paper
- Wax paper
- Paper: printer paper
- Construction paper: black, white, red, blue and yellow: one colour, such as blue
- A tape measure, or a long ruler
- ✂️ Kid scissors
- 📏 A ruler
Steps
- Cut ten squares, about 8 cm wide, from each of the four kinds of paper.
- Lay the flashlight on a table 30 cm from a bare wall, pointing at the wall.
- Make the room dim and switch the flashlight on: you will see a bright spot on the wall.
- Hold one tissue square flat on the flashlight's glass and look at the spot on the wall.
- Add squares one at a time until the spot is gone, and stop at ten if it is still there.
- Write how many layers it took in your table under Try 1.
- Do the tissue paper two more times, and write each number down.
- Do three tries with wax paper, then printer paper, then construction paper.
- Find the middle number for each kind of paper and draw a bar graph.
Every step is one you can do yourself, with a grown-up nearby. Write each number down straight away, in the table below, so nothing is lost.
Your results table
Name ______________________ Fair day ____________
Question: How many paper layers block a flashlight?
I changed: Kind of paper I measured: how many layers it takes before the light on the wall is gone (layers)
| Kind of paper | Try 1 (layers) | Try 2 (layers) | Try 3 (layers) | Mean |
|---|---|---|---|---|
| Tissue paper | ||||
| Wax paper | ||||
| Printer paper | ||||
| Construction paper |
MY GRAPH (a bar graph: kind of paper along the bottom, layers up the side)
What I noticed: ______________________________________________
From 4th grade, add the tries for each level and divide by how many there were: that's the mean, and it goes in the last column. Then draw a bar graph, one bar for each thing you tried.
Name ______________________ Fair day ____________
Question: How many paper layers block a flashlight?
If I change the kind of paper, then how many layers it takes before the light on the wall is gone will ________________, because _____________________________________________
| I CHANGE | I MEASURE | I KEEP THE SAME |
|---|---|---|
| Kind of paper: Tissue paper, Wax paper, Printer paper, Construction paper | how many layers it takes before the light on the wall is gone (layers) |
|
What I think will happen, in my own words:
Name ______________________ Fair day ____________
Question: How many paper layers block a flashlight?
| Date | What I did | What I saw | What I think |
|---|---|---|---|
Name ______________________ Fair day ____________
Question: How many paper layers block a flashlight?
| Date | What I did | What I saw | What I think |
|---|---|---|---|
Name ______________________ Fair day ____________
Question: How many paper layers block a flashlight?
| Date | What I did | What I saw | What I think |
|---|---|---|---|
Name ______________________ Fair day ____________
Question: How many paper layers block a flashlight?
My hypothesis was ☐ right ☐ partly right ☐ not right.
I know because my numbers show:
What surprised me, or what might have gone wrong (7th and up):
Next time I would test:
Idea: Change a second thing: test construction paper in black, white and yellow, and graph the layers each colour needs.
Why it works
Paper stops light by soaking some of it up and bouncing some in many directions, and each layer takes a bit more. Thin, see-through kinds such as tissue paper let a lot through, so it can take many layers. Thick paper, such as construction paper, stops more light with each layer, so it usually needs only a few.
Going further (7th and up): Change a second thing: test construction paper in black, white and yellow, and graph the layers each colour needs.
Board layout
- ❓ Question (10 × 8 in): How many paper layers block a flashlight?
- 💭 Hypothesis (10 × 9 in): If I change the kind of paper, then how many layers it takes before the light on the wall is gone will ______, because ______.
- 🧺 Materials (10 × 12 in): 6 things: see your list.
- 🪜 Steps (22 × 9 in): 9 steps, three tries at each level.
- 📊 Results (22 × 16 in): Your table (Kind of paper down the side, tries across) and your bar graph.
- ✅ Conclusion (10 × 14 in): My hypothesis was right / partly right / not right. I know because…
Materials to list: A flashlight; Tissue paper; Wax paper; Paper; Construction paper: black, white, red, blue and yellow; A tape measure, or a long ruler.
Bring photos or drawings of your test. Nothing wet, hot, powered or alive on the table.
This project at your grade
| 1st–3rd grade | Tries: three at each level (one is fine at a first fair). The table: levels and tries, numbers or pictures. The graph: a picture, or a simple bar graph. The conclusion: what happened, in their words. |
|---|---|
| 4th–6th grade | Tries: three at each level. The table: units in the header and a mean column. The graph: a bar graph, or a line for a number that grows. The conclusion: right, partly or not, and the numbers that show it. |
From 4th grade up, the table gets a mean column. See every project for 2nd grade, or print a blank results table.
What a judge will ask
- What did you change, and what did you measure? I changed the kind of paper and measured how many layers it takes before the light on the wall is gone, in layers.
- What did you keep the same, and why does that matter? I kept squares of paper cut to the same size and adding one layer at a time the same, so the only difference was the kind of paper.
- How many times did you test it? 3 times at each of my 4 levels.
- If you did it again, what would you change or test next? I'd test construction paper in black, white and yellow, and graph the layers each colour needs.
Make it yours
Keep this project on this device and Peabody counts down to your fair day, with a plan for each day. Nothing is sent anywhere.
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