Drop a rock in water. It sinks to the bottom! Drop a cork in water. It floats on top! Sinking and floating are properties of solids.
Heavy things do not always sink. A giant ship is very heavy, but it floats. Its shape helps push water away. Small things do not always float. A tiny coin sinks fast!
Scientists make predictions before testing. Then they test each object the same way. Today you will predict which solids sink or float. Then you will test them and record your results.
1. What happens when you drop a rock in water?
2. Do heavy things always sink? Give an example.
3. What do scientists do before they test?
Ask a grown-up before putting anything in water. Do not test electronics, books, or anything that should stay dry. Wipe up splashes right away. Never taste the test water.
You need: a big bowl of water, a towel, and six small solids. Try a coin, a cork or crayon, a spoon, a plastic toy, a rock, and a leaf.
Predict first! Then gently drop each object in the water. Watch what happens. Record your results on page two.
Circle your prediction. Then circle what really happened.
| Object | My prediction | Result |
|---|---|---|
| Coin | sink / float | sink / float |
| Cork or crayon | sink / float | sink / float |
| Metal spoon | sink / float | sink / float |
| Plastic toy | sink / float | sink / float |
| Rock | sink / float | sink / float |
| Leaf | sink / float | sink / float |
Pick two objects you tested. Fill in a property card for each.
| Property card 1 | Property card 2 |
|---|---|
| Object: __________________ | Object: __________________ |
| Hard or soft? ______________ | Hard or soft? ______________ |
| Heavy or light? ____________ | Heavy or light? ____________ |
| Sink or float? _____________ | Sink or float? _____________ |
Draw your bowl of water. Show the floaters on top and the sinkers on the bottom.
1. Which object surprised you the most? Why?
2. What was the same about the objects that floated?
Pick one object that sank. Can you make it float? Try resting it on a plastic lid or foil boat. Draw your idea below.
Did your idea work?
Write today's date in your journal. List your sinkers and your floaters. Write one sentence about your biggest surprise.
At bath time, test one new bath toy. Predict first, then test. Tell your family if your prediction was right.