🔦 Does a toy's shadow get bigger when the flashlight comes closer?

My hypothesis

If I change how close the flashlight is, then how many crayons wide the shadow is will ______, because ______.

🔊 You fill in the blanks. Think about what happens to your hand's shadow when you hold it near a lamp. A guess is a good because: the test finds out.

Change, measure, keep the same

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 3 levels 3 times.

What you need

• 🔦 A flashlight
• 🚗 A toy car: a toy to make the shadow
• 🩹 Masking tape, to mark lines: three marks on the floor
• 🖍️ Crayons or markers: a box of the same size
• 📄 Paper
• 🩹 Tape

Steps

1. Stand the toy on the floor near a wall, in a room with the lights off.🔊
2. Your grown-up puts three tape marks on the floor: far, middle and close.🔊
3. Hold the flashlight on the far mark and shine it at the toy.🔊
4. Lay crayons end to end across the shadow on the wall, and count them.🔊
5. Your grown-up writes the number down. Do it two more times.🔊
6. Shine it from the middle mark three times, and the close mark three times.🔊
7. Colour a box for every crayon. Where was the shadow biggest?🔊

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

Write each try's number in its box. Then draw a bar graph, one bar for each thing you tried.

Why it works

🔊 A shadow is where the toy blocks the light. When the light is close, the toy blocks a big part of it and the shadow spreads wide, and when the light is far away, the shadow is smaller.

Going further (7th and up): Change a second thing: move the toy closer to the wall and farther from it, with the flashlight in one place.

My picture board

A kindergarten board is one page: the question, a guess to tick, a drawing of the test, a box coloured for each count, and what your child found out, in their words. Glue it to a folded card, or the middle of a tri-fold.

Board layout

This project at your grade

From 4th grade up, the table gets a mean column. See every project for kindergarten, or print a blank results table.

What a judge will ask

• What did you change, and what did you measure? I changed how close the flashlight is and measured how many crayons wide the shadow is, in crayons.
• What did you keep the same, and why does that matter? I kept the same toy and the toy in the same place the same, so the only difference was how close the flashlight is.
• How many times did you test it? 3 times at each of my 3 levels.
• If you did it again, what would you change or test next? I'd move the toy closer to the wall and farther from it, with the flashlight in one place.

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.

Try next

• 🔦 Does a shadow grow when the light comes closer?1st–4th grade · 1 day of testing · free🌦️ Growing and weather · ✂️ Paper, tape and toys
• 🌱 Where does grass come up first: a sunny window, a shady room or a dark cupboard?kindergarten · 10 days of testing · about $3🌦️ Growing and weather · 🌱 Outside and plants