Second Grade Engineering -Catapults

Introduction to Second Grade Engineering -Catapults

-Next Generation Science Standard* K-2-ETS1-2

When I have a chance to do projects using simple household items, I jump at the opportunity.  This particular Second Grade Engineering project was super fun and it covered one of the Next Generation Science Standards* in engineering, technology, and applications of science. I originally saw a version of this on an awesome website called Housing a Forest.  When you have time, check out that site for other really fun, inexpensive, projects.

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Materials List for Second Grade Engineering -Catapults

-sturdy piece of wood
–clothespins
–hot glue gun
–plastic teaspoon
–large wood craft stick
-cap from juice container
-various light items to catapult
–measuring tape
–Kindergarten through Second Grade Engineering -Catapults lesson

Step 1: Download the Kindergarten through Second Grade Engineering -Catapults lesson and complete the worksheets

Here is a sample of one the worksheets:

Step 2: Gather all the materials and build your catapult following the directions below

As a base for our catapults, we used a container from Carnation Instant Breakfast.  You can use a sturdy piece of wood if you don’t have these containers. We have a lot of these because Jack drinks it everyday since he was around one year old.  He was prescribed this to help him gain weight and stay on the growth curve.  Anyway, it is a sturdy and flat container which was perfect.  We glued clothespins onto it with a hot glue gun.  I don’t think regular school glue would be strong enough.  The trick is to put the clothespin on the bottom so that the mouth of it opens toward you.  Then you put another clothespin on top of that so the mouth of it opens away from you.  This gives more stability when catapulting.  We chose to use a plastic teaspoon on one side and a large wood craft stick on the other side with a cap from an orange juice container on the end of it.

Step 3: Begin to fill in the data table from the lesson

The reason we used two catapults was so that we could conduct a science experiment to see which would work the best at shooting items across the room.  I wanted to be sure we could go through the scientific method by forming a hypothesis and collecting data.

Step 4: Choose the items you will shoot from the catapult, have your measuring tape ready, and begin testing

Now it was time to start testing!  We chose five items to test, mini marshmallows, pom poms, cotton balls, rice krispies and popcorn, but you can use any lightweight items you have on hand.  I explained to Jack that the scientifically appropriate way to conduct an experiment is to do everything the same way each time except for what you are testing.  Therefore, he had to shoot the catapult from the same place, with the same force each time.  The only thing that was changing was the item we were shooting.

I asked Jack to state his hypothesis for which he thought would shoot farther, the spoon or the wooden stick, and why he thought that.  He said the spoon would shoot further, but he wasn’t sure why.

Here is Jack shooting the pom pom off the catapult.  I don’t have a picture of it here, but after each shot, we measured how far the item went with a measuring tape in inches.

Step 5: Go over your data and answer the catapults questions

Here is the data table we kept after each shot.  Some of the items went forward, some went on a diagonal, some went backwards, and others straight up in the air.  Since we didn’t have a reliable source of measuring those that went straight up, we counted those as do overs.

As you can see, the cap worked better at shooting items forward and the item that went the furthest was the pom pom.  I asked Jack why he thought that was the case.  He said because it was lighter than the other items.  I told him the rice krispies and popcorn were light as well and he said he wasn’t sure then.

I explained to him that in order to do a science experiment well, you have to take multiple sets of data.  So we did a second round of shots.  Unfortunately, we did not record the data, but we did find that the numbers were similar for a few items and changed significantly for others.  Rather than learning what item shoots the furthest, Jack learned that data can change the more times you do a test and it is the average number that matters.

Step 6: Complete the Catapult Design Challenge

To cover the NGSS* Engineering and Design standard, we completed a catapult design challenge to help rescue a princess from a castle.  The challenge was to design a catapult to send rope to the princess so she could escape from the tower.

Step 7: Complete the assessment pages in the Kindergarten through Second Grade Engineering -Catapults lesson

Here is a thumbnail of the assessment:

Source:

NGSS Lead States. 2013. Next Generation Science Standards: For States, By States. Washington, DC: The National Academies Press.

*”Next Generation Science Standards (NGSS) is a registered trademark of Achieve. Neither Achieve nor the lead states and partners that developed the Next Generation Science Standards were involved in the production of this product, and do not endorse it.”