Parts of the Whole: Matter

Parts of the Whole: Matter

Parts of the Whole

This concept is fairly easy, but it takes just a little bit of thinking to go along with it. As with most things in Science, if you take your time, use your strategies, and do your best, you will soon find you have mastered Parts of the Whole

Hershey Bar

Let's consider this Hershey Bar. It is 1.55 ounces. What would happen to the weight if I broke it into the sections and weighed the sections together? Certainly since these pieces are smaller it would weigh less. Well, let's find out!!

Hershey in Pieces

As we weighed these we find that all the pieces together weigh 1.55 ounces, which is EXACTLY what the whole bar weighed. That has to be coincidence, right? Maybe we didn't break it into small enough pieces. Let's use a cheese grater on it and grate it into tiny pieces to find out.

Grated Chocolate

Hmmm? The grated chocolate weighs 1.55 ounces. That's the same as the whole. What could this mean? Maybe it isn't coincidence.

Do Legos do the same thing?

OK, maybe it's a chocolate thing. Let's try it with Legos. We will build a quick structure and weigh it. Then we will break it apart and weigh the pieces to see if they match the whole.

Lego Pieces

Whoa!! Same thing this time. The pieces and the whole weigh the same. WAIT!! I've got it, I thought of a way it won't work...I think.

Ice

If I take ice and weigh it, then MELT It, there's no way it can be the same. We've done it, we've cracked the code. Let's try just to be sure.

Melted ice Cube

Well I give up. It looks like we have proven something scientific. We can now say that "The sum of all the pieces is equal to the whole".

Multiple Choice

A 100 kg rock is broken into five smaller rocks for a garden. What is the total mass of all five smaller rocks?

• 20 kg

• 50 kg

• 100 kg

• 500 kg

Rocks

Think of it like this. When I have the whole rock, all of the matter (the stuff inside the rock) is all there right? When I break it into pieces and weigh all the pieces, have I lost anything, or just changed the size if the original object? If I am not losing anything, it has to be equal. All of the parts are equal to the whole.

Multiple Choice

Barb has a bucket of snow with a mass of 20 kg. After the snow melts, what will most likely be the mass of the bucket of water?

• 15 kg

• 20 kg

• 35 kg

• 40 kg

Bucket of Snow

Remember when we studied Solids, Liquids and gas and we talked about the molecules in each? The only change between snow and water is how close the molecules are. We are not gaining or losing any molecules as it changes state.

I wonder...

So what if the parts come from different things, not like breaking one rock into pieces, but putting things together, like making a sandwich? If you weighed each piece, the bread, the meat, the tomato, the lettuce you would know EXACTLY what the whole sandwich would weigh by adding the parts together. Let's try it!

Multiple Choice

Elsa is making a grilled ham-and-cheese sandwich. She uses a 20-gram slice of cheese, 40 grams of sliced ham, and two 15-gram slices of bread. After she heats the sandwich on a griddle, the cheese is melted. What will be the mass of her sandwich?

• 55 grams

• 60 grams

• 75 grams

• 90 grams

Wait a minute!

What would happen if you poured 10g salt into 10 g of warm water? The salt disappears so it would only be 10g, right? Let's try it in class to see! 👀

What happened?

So the salt dissolves in the water. The molecules are still there. We don't have a change in mass because we are not losing any matter. Let's see if you get this.

Multiple Choice

Maya adds 6 grams of sugar to a bottle containing 14 grams of warm water. What is the total weight of the sugar and water?

• 6 grams

• 8 grams

• 14 grams

• 20 grams

OK, OK, I get it now

Let's find out if we do. We're going to take a short "quiz" to see how we should proceed from here.

Multiple Choice

The mass of a piece of copy paper is 10 grams. Katie tears the paper into 4 equal sections. What is their combined mass?

• 5 grams

• 10 grams

• 20 grams

• 40 grams

Multiple Choice

A jeweler melts gold to make jewelry. As the gold melts, the mass

• increases

• decreases

• is destroyed

• stays the same

Multiple Choice

If 10 grams of water are added to 5 grams of salt, how much salt water will be made?

• 2 grams

• 5 grams

• 10 grams

• 15 grams

Multiple Choice

A teacher adds 2 g of chalk to 25 g of vinegar in a tightly sealed jar. The chalk and vinegar react, and gas bubbles form. What is the total mass of the jar’s contents after the reaction takes place?

• 23 g

• 25 g

• 27 g

• 50 g