Spring 2006

Materials tip: Using the Properties of Matter Digital Balance
The STC/MS kit Properties of Matter includes 4 digital balances that are used throughout the unit. These electronic balances are sturdily constructed, but like any electronic device they should be handled appropriately at all times by students. Here are some helpful hints to keep your balances working properly.

1. Unpacking and setting up
	Remove the tape holding the pan in place.
	Remove the red retainer under the pan, which was used as a cushion during shipment.
	Insert the 3 AA batteries that came with the balance in the sequence shown in the bottom of the battery compartment.
2. Using the balance
	Gently press the On/Off button to turn on the balance. Note: The device automatically shuts off after 5 minutes of inactivity to save the batteries.
	Gently pressing the On/Off button will tare, or "zero," the balance if nothing is on the pan. If you do have a container on the pan, press this button again and it will "zero" the container and weigh only what you add to it.
	Gently place the object to be weighed in the center of the pan.
3. Misusing the balance - There are 2 primary ways to damage the balance.
	Overloading: The maximum weight capacity for this balance is 200 g, which is only 7 oz or 0.4 lbs. Make sure students weigh only objects that do not exceed this maximum! If the object/substance being weighed exceeds 200 g, the balance’s display will show an “E,” indicating an overload. The overload object/substance should be immediately removed from the scale. Repeatedly overloading the balance can destroy its internal electronics.
	Pressing the On/Off button too hard: The On/Off button is delicate and requires just a slight touch to turn the balance on or off. Repeatedly pressing the button with too much force will break it.
4. Warranty
	The maker of this balance, Ohaus, guarantees its equipment for one year. The balance’s instruction booklet states (pg. 6) that "these scales are warranted against defects in materials and workmanship for a period of 12 months from the date of delivery. Ohaus will repair or replace any component(s) that prove to be defective at no charge, provided that the product is returned, freight prepaid, to Ohaus....This warranty does not apply if the product has been damaged by accident or misuse, exposed to radioactive or corrosive materials or has foreign material inside of the balance."
	If your school or district chooses to ship what you believe is a defective balance back to Ohaus for repair, it will be the school/district’s responsibility to pay the shipping charge.