Sir Isaac Newton would be proud: Can you catch the Boo Bomb or will you use too much force and break it?
Newton’s First Law of Motion: An object in motion stays in motion unless an external force is applied against it.
There’s a lot of ways to teach this, but nothing is as fun as a good old-fashioned egg toss at Halloween. Except we call them…Boo Bombs.
Boo Bombs are perfect for an introduction to physics.
If you think about it, there is actually a lot science behind the concept of tossing an egg (and catching it) successfully. But first you have to set the stage for this Halloween science lesson.
- Blow out enough eggs for each student to have 3-4 (just like Easter eggs)
- Rinse them out and fill with 1 teaspoon of flour each
- Cover the hole with tape
- Draw 2 eyes and a mouth to make each egg look like a ghost
The Demonstration
Before allowing students to do the egg toss, do a quick demonstration. You will need a large bed sheet and one egg.
Ask 4 students to each hold a corner of the bed sheet. The two students at the front should kneel down and the two at the back stay standing; the sheet should be at an angle and held tightly.
Ask the children what they think will happen when you toss a Boo Bomb on the sheet. If you teach younger ones like I do, the responses range anywhere from, “The egg will crack open” to “I hope it smashes!”
**Have them record their predictions on the tri-fold brochure found at Halloween Science: Ghost Rockets***
Of course, the Boo Bomb doesn’t break as long as the sheet is held tightly. Ask them to describe what happened.
- It rolled
- It bounced
- The sheet wiggled
“The sheet wiggled” is a great answer because it shows a preliminary understanding of the dispersion of force. The Boo Bomb will not break because the sheet gradually slows the motion of it.
Now throw the Boo Bomb against a wall (the kids LOVE this!). Why does it break? Because the wall doesn’t slow the motion of the egg gradually – it does it all at once.
The Experiment
Can the students find a way to toss Boo Bombs to each other without breaking them?
How can they imitate the “wiggle” motion of the sheet when they catch their Boo Bombs? (No, this doesn’t mean they wiggle their arms. They need to gradually slow the motion of the egg as they catch it by moving their arms back similar to the way a football player catches the ball).
Hopefully the students will be wearing old clothes to school on the day you do this experiment, because many of them will be covered with flour when their Boo Bombs break in their hands or over their heads.
Quite a few will catch on quickly and will go for a long time with their Boo Bomb throws. And if you have some left over at the end, let them try to throw them into the sheet from different angles.