Today you will make texture rubbings! A rubbing is a picture of a surface. Here is how it works. Put paper on top of a bumpy surface. Rub the side of a crayon across the paper. The bumps show up like magic!
Rubbings work best on rough surfaces. Coins, tree bark, and baskets make great rubbings. Smooth surfaces, like a mirror, make almost no picture at all. Can you guess why? The crayon needs bumps to catch on!
You will also test hardness today. Scientists test hardness by pressing materials with a fingernail. If your nail leaves a mark, the material is softer. If it leaves no mark, the material is harder.
1. What kind of surface makes the best rubbing?
2. Why does a smooth mirror make almost no rubbing picture?
Ask a grown-up for help choosing safe surfaces to rub. Do not press your nail into anything sharp or breakable. Never test hardness on someone else's things without asking.
You need: thin paper, a crayon with the wrapper off, and 3 bumpy surfaces.
Steps: 1. Put paper on the surface. 2. Hold it still. 3. Rub the crayon on its side. 4. Look at your picture! Record each rubbing below.
| Surface I rubbed | Rough or smooth? | Did the rubbing work well? |
|---|---|---|
| YES / A LITTLE / NO | ||
| YES / A LITTLE / NO | ||
| YES / A LITTLE / NO |
Write each object in the best column: crayon, spoon, eraser, rock, banana, coin.
| Softer (nail leaves a mark) | Harder (no mark) |
|---|---|
With a grown-up, pick four safe objects. Gently press your fingernail on each one. Record what happens.
| Object | Did my nail leave a mark? | Harder or softer? |
|---|---|---|
| YES / NO | ||
| YES / NO | ||
| YES / NO | ||
| YES / NO |
Write your four objects in order from softest to hardest.
1 (softest): ______________ 2: ______________ 3: ______________ 4 (hardest): ______________
Tape or copy your favorite rubbing here, or draw what it looks like.
Which surface made the best rubbing? Why do you think it worked so well?
Make a rubbing of a secret surface. Show it to someone in your family. Can they guess what surface you used?
My secret surface was: ______________________________
Their guess was: ______________________________
Were they right? YES / NO
Write today's date in your journal. Then answer:
The hardest object I tested today was:
One thing that surprised me was:
Take a walk outside with a grown-up. Find the roughest surface and the smoothest surface you can. Make a rubbing of one if you can bring paper and a crayon!