From 987c324833e98976a3f2e6884740a726062d988c Mon Sep 17 00:00:00 2001
From: Denzell Barnett <deba7535@colorado.edu>
Date: Wed, 9 Jan 2019 10:18:33 -0500
Subject: [PATCH] Update model.md

https://github.com/phetsims/masses-and-springs-basics/issues/49
---
 doc/model.md | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/doc/model.md b/doc/model.md
index d899721..da98dc5 100644
--- a/doc/model.md
+++ b/doc/model.md
@@ -1 +1,4 @@
-TODO model description
\ No newline at end of file
+# Masses and Springs: Basics - model description
+This simulation is a subset of the Masses and Springs simulation. The model is derived from MAS and is consistent with that sim. Energy values are not included in MASB.
+
+For details on the model for Masses and Springs, see https://github.com/phetsims/masses-and-springs/blob/master/doc/model.md.