To calculate the weight of 1000 baseball cards, we first need to determine the average individual weight of a standard baseball card. The standard size for a modern baseball card is 2.5 inches by 3.5 inches. Most cards are printed on thick glossy card stock paper that is between 16pt-20pt thickness. The typical weight for an individual baseball card made from this type of card stock ranges from about 0.2 grams to 0.3 grams.

So for our calculations, we will use an average individual weight of 0.25 grams per card. With 1000 cards, to determine the total weight we would use the formula:

Individual Weight x Number of Items = Total Weight

Plugging in the numbers:

0.25 grams x 1000 cards = 250 grams

So 250 grams or 0.25 kilograms would be our preliminary answer for the weight of 1000 standard baseball cards.

It’s important to note that there can be some variation in the individual weights depending on a few factors:

Card stock thickness: Heavier card stock around 20pt would weigh slightly more than lighter 16pt stock. An 0.02 gram difference per card could add up overall.

Foiling/embossing: Cards with foil autographed signatures or embossed logos/mascots may weigh a tiny bit more than plain printed versions.

Condition/wear: Heavily played cards could potentially lose a fraction of a gram through minor creasing, bending or edging over time. Mint condition would weigh slightly more.

Year/manufacturer: Older vintage cards as well as lower quality reprint variants may use somewhat different card stock mixtures that impact weight slightly.

Inserts/parallels: Special parallel printings, autographed cards, memorabilia cards with patches or other embellishments would definitely weigh more than a standard base card.

To account for these potential variances, we should add a small margin of error to our initial calculation. Let’s assume:

75% of cards are standard 0.25g weight

15% weigh 0.02g more at 0.27g due to thicker stock or touches of foil

10% weigh 0.03g less at 0.22g due to wear and lighter stock.

Calculating it out:

0.25g x 750 cards = 187.5g
0.27g x 150 cards = 40.5g
0.22g x 100 cards = 22g

Total = 187.5g + 40.5g + 22g = 250g

So to summarize, for a collection of 1000 standard modern baseball cards in assorted conditions, printed on typical 16pt-20pt card stock, the estimated total weight would be approximately 250 grams or 0.25 kilograms allowing for minor individual weight variations. Of course, if the collection contained substantially more premium cards with heavier embellishments, signatures or memorabilia pieces, the weight could potentially exceed this estimate. But for a typical large bundle of 1000 baseball cards acquired all at once, 250 grams is a reasonable assumed total weight while accounting for the ranges involved. Let me know if any part of the explanation needs further clarification or details.