T H E   N I H    C A T A L Y S T    J A N U A R Y  – F E B R U A R Y   2006


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In Future Issues...

Inflammatory Statements

Bench to Bedside

Obesity Research



Kids' Catalyst


We're going to travel to the stars again . . . or just to the kitchen . . . to see how those big holes in moons and planets (including our own) are created.

 When you look at the moon, you can tell that it s had more than a few interstellar encounters over the millennia that were strong enough to leave their mark: craters. Some large, some (relatively) small, these craters reveal hints about their origin that scientists analyze to figure out the shape of what hit the crater (asteroid), at what angle it was going when it hit, and how big it was.

 So let's go to the surface of our own planet. What we'll need for this experiment is:

 1. Flour, at least five cups, but you may end up using a five-pound bag. Expect to be covered in flour before we're done, so wear your jeans!

2. A shallow, long tray or box and a plastic bag to line it with. Something like a litter box would be perfect, but don't use it if it's not new! Yuck!

3. A rolling pin.

4. Marbles, beans, or just about any small object you wouldn't mind being covered in flour.  No siblings allowed.

5. Contrasting powders. I used the strawberry and chocolate flavors of milk drinks, but you can certainly use colored sugar or any other nontoxic powder you wish.

6. A chart (that we'll make).

Now we're going to make a powder layer cake. Just as the surface of planets have different layers, so will our cake. Pour in enough flour to line the bottom of the tray and even out with the rolling pin. Sprinkle a thin layer of chocolate powder, then another thick layer of flour (evening out again), and finally some strawberry.

Take a bean and drop it into the powder from waist level and see what happens. Did you get all the way down to the bottom layer? Do you see chocolate on the surface now? Does it help with sound effects (just kidding).

Move to another section and drop another bean from over your head, and see the difference. Try this with different heights, different objects, and different angles,  writing down your observations as you go. You can even vary how tightly packed the flour is. You can clearly see that the pattern in the flour is different for a bean dropped straight down from waist-high from one flung from the side. How do the other variables affect the pattern in the flour?

 Scientists use a very similar experiment to reproduce craters, and they can predict what impact an asteroid can make. The actual crater itself may smooth over time—which helps us predict its age—but the mark will always be there, proving an encounter in the stars.

Jennifer White

The NIH Catalyst is published bi-monthly for and by the intramural scientists at NIH. Address correspondence to Building 2, Room 2E26, NIH, Bethesda, MD 20892. Ph: (301) 402-1449; fax: (301) 402-4303; e-mail: <catalyst@nih.gov>.

Michael Gottesman
Deputy Director for Intramural Research, OD

John I. Gallin
Director, NIH Clinical Center

Celia Hooper



Fran Pollner

Shauna Roberts

Jennifer White


Jorge Carrasquillo, CC
David Davies, NIDDK
Dale Graham, CIT
Elise Kohn, NCI
Susan Leitman, CC
Bernard Moss, NIAID
Michael Rogawski, NINDS
Joan Schwartz, NINDS
Gisela Storz, NICHD


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